Guess What Will Happen: Battery Desulfation Experiment - Page 1
Forum section: electronics / projects

author: TheRuler8510
author_rank: Regular Contributor
timestamp: February 15, 2015, 05:17:30 pm
content: Guess What Will Happen: Battery Desulfation ExperimentI bought a 12V, 12 AH size, lead-acid battery from Radio Shack during their liquidation sale (75% discount) , and it turns out to be completely dead, showing 0.002V and will not take a charge at all. Dummy me for not checking it first.Since I can't return it, I plan to run an experiment that I always wanted to try. I will put a desulphator on it for day, weeks even months, to see what happens. It is running now. I hooked in parallel another 12V battery of similar size, that it needs to run. It is pulsing 110V pulses at 1 KHz.So, your challenge is to guess what will happen, will this battery ever regain any life at all? Or is it a total loss and waste of time?Enter your guess or opinion, and I will report back periodically as to progress.Regards,

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 15, 2015, 05:22:37 pm
content: Use a standard light dimmer and 1uF or so mains rated cap in series to a bridge rectifier. Set the dimmer about halfway and it will nicely generate the fast spikes that are needed to desulfate a battery.

author: Seekonk
author_rank: Super Contributor
timestamp: February 15, 2015, 06:39:03 pm
content: I give it some hope because it was never used (are you sure of that?) but not much. I have a solar camp and get a lot of batteries from the town recycling. When those are test below 5 or 6V, they will never recover and I would be happy with 2-3AH.

author: tautech
author_rank: Super Contributor
timestamp: February 15, 2015, 06:57:24 pm
content: I'd be surprised if you get that battery to recover to a state of usefulness.It may bounce back for light use, but anything like 12 AHPlayed with LA desulfating for ~20 years and yes it is useful.Units Iwould produce 70V 6A pulses @ 1 KHz.Neat to see the battery OC voltage rise after a session on the desulfator.Good luck but I don't like your chances.

author: SeanB
author_rank: Super Contributor
timestamp: February 15, 2015, 07:06:46 pm
content: Sealed batteries need water added, and i had some moderate success with popping the top plate off and adding water ( around 15ml per cell) then gluing the top back down. Charge overnight with a current limited 24V supply and see the next morning if it recovered somewhat. About 1 in 10 got good capacity back, but the cheap ones never did.

author: mikerj
author_rank: Super Contributor
timestamp: February 15, 2015, 07:40:45 pm
content: If this is a gel battery then you have almost no hope at all. If it's a proper lead acid or AGM battery them you might coax some life into it, but it will never meet it's new specs.

author: Fraser
author_rank: Super Contributor
timestamp: February 15, 2015, 08:11:37 pm
content: To the OPHave you ever seen inside a sulphated AGM battery ?If you have, you would know the damage that can occur in the gel mat and plates. This is not an absolute however so you may be lucky. I have tried, on many occasions to preserve and recover the capacity of AGM batteries. If AGM batteries have sat at less than around 11V for more than 6 months they may as well be a capacitor. I have been known to prove this by applying over 120V D.C to such a battery in a demonstration of 100% sulfation....... the battery did not take a charge even with such abuse and indicated only a few mA's of current draw. If it will not draw enough current, its hard to convert its chemistry back into a useful battery/cell. If it draws a reasonable current at 14.8V it should recover OK after some TLC.Sadly it is my personal experience that a deeply discharged AGM battery that has remained discharged over a long period, is beyond recovery to any meaningful capacity and even if you strike lucky, would you truly trust such a battery ?You have nothing to lose by trying recovery techniques but the laugh would be if you expend money on a 'special' charger (plus your time), that actually exceeds the value of the battery. Good money after bad ? Just my 2 CentsUpdate: This web page details sulfation, what it is and possible recovery methods. Remember what I said though..... investment Vs return has to be considered if you do not already have teh correct equipment.http://bestbatteries.co.nz/battery-care/battery-faults.htmlAurora

author: cosmicray
author_rank: Frequent Contributor
timestamp: February 15, 2015, 08:25:13 pm
content: You might want to keep some baking soda handy, just in case you have an unfortunate core breach.

author: Fraser
author_rank: Super Contributor
timestamp: February 15, 2015, 08:48:21 pm
content: This thread brought back happy memories of maintaining my collection of various AGM batteries. I was in Australia at the time and wanted a means of exercising the batteries as Pb based technology likes to be used in order to provide a long life. Sounds odd doesn't it...yep Pb batteries do not like sitting on charge doing nothing unless they are specifically designed to cope with such stand-by conditions.I had the correct 2 stage chargers but no way to discharge the batteries automatically so that they went through an automatic charge-discharge-charge-discharge-charge cycle once a month. This was back in 1990 and I know a PIC controller could do this in its sleep but I went the analogue route.The charger had a 'Chargeng' LED that I tapped for the 'full' state detection (it switched off with no battery or a charged battery) and I used a simple comparator to set a battery discharged (empty) threshold. A relay was controlled by these two state indicators via a transistor (or two?) and this relay applied either the charger or a resistive load to the battery. It only took a heavy duty relay and a few common components to build the little switching unit.Once connected to the battery, the circuit continuously cycled through the charged & discharged states until disconnected. This simple attachment not only kept my good batteries healthy, but also recovered the capacity of some of my lazy batteries that may have been partially sulfated. I still have that little veroboard circuit knocking around in the loft somewhere. I can certainly recommend a battery exerciser.Aurora

author: Muttley Snickers
author_rank: Unknown
timestamp: February 15, 2015, 09:39:15 pm
content: The battery that the OP is conducting a test on will have a date code and this information is relevant in regards to the batteries ability to recover. If the battery is a few years old and in addition to the initial measurement of 0.002 which is rather low and I suspect possibly had its day, my money is on its buggered.However, if the battery date is recent and no other faults are present then these can come back from the dead but are never the same.

author: Circlotron
author_rank: Super Contributor
timestamp: February 15, 2015, 09:51:50 pm
content: Back in 1990 I worked at a place that sold UPSs. Some had been in storage for several years and the batteries would be replaced before sale. The old batteries would be typically at 1 or 2 volts. I experimented a whole heap with the old batteries and eventually had great success with the following formula: Apply a REVERSE charge with current limit set to 2% of Ah rating for 48-72 hours. The battery may not draw any current initially but just leave it alone. After this time, set the charge to normal polarity and charge for 3-4 days, still with the 2% current limit. During this time, do NOT be tempted to wind up the current limit - one cell will start to get hot and then it is junk. Fixed many new but neglected batteries this way. One 12v 24Ah SLA Yuasa started off at 2 volts and had been sitting for about 3 years, got it going and used it in my Diahatsu Charade for 2 years until I sold it.

author: eneuro
author_rank: Super Contributor
timestamp: February 16, 2015, 07:51:18 pm
content: Quote from: TheRuler8510 on February 15, 2015, 05:17:30 pmWhat about duty cycle?I havedesulfator modein my custom car battery charger, but maximum voltage after transformer is 24Vmax and duty cycle <10% .BTW: Desulaftor mode is switched on by.... shorting inductor in buck converter with 2 x IRFZ44N in parallel on lead-acid battery minus (-) terminal.However, without capacitors after diodes bridge mosfets worked like 55V Zeners in avalanche while voltage maximum across this switch was about 65Vmax etcAnyway at low duty cycle those caps create nice 24Vmax, so while there is bypassed inductor I have quite nice desulfator when neededThere is about 5% @ 1kHz in one of those 555 based desulfators which were inspiration to my ATTiny85 based:Do you have some recomendations about this duty cycle and preferable frequency and Vmax in those desulfators for 12V lead-acid car batteries?

author: tautech
author_rank: Super Contributor
timestamp: February 16, 2015, 08:16:33 pm
content: Quote from: eneuro on February 16, 2015, 07:51:18 pmDuty cycle for a 555 based unit is dependant on the inductor chosen/built in order not to saturate it.1 KHz is just a convenient switching frequency, however the pulse edges are many times this.The desulphation is performed by the voltage developed from the colapsing field back emf when current to the inductor is switched off.Each battery will absorb this back emf pulse in a different way, results scoped at the battery terminals will be different to those at the desulfator output.For efficiencies sake short heavy leads are a must.

author: eneuro
author_rank: Super Contributor
timestamp: February 16, 2015, 11:15:04 pm
content: Quote from: tautech on February 16, 2015, 08:16:33 pmProbably this is most classic desulfator circuit I've found when was looking for such sort of things a few years ago:http://www.frontiersprings.com/desulfator.htmlAnyway IRF9Z34P-channelmosfethttp://www.vishay.com/docs/91092/91092.pdfis wrong drawn in thisfrontierschematics, so it might be a trapHowever, I do not liked messing with inductors and 555 while it is was only a few lines of code on AVR to add support for desulfator mode to battery charger.It doesn't mater how 1kHz frequency is created, but knowledge of proper duty cycle might be critical, so it will be difficult to compare different available desulfators without its waveform specyfication

author: TheRuler8510
author_rank: Regular Contributor
timestamp: February 17, 2015, 11:53:51 am
content: Update & more info:I don't know if it is a gel-cell or AGM, but the exact battery I am using is this:http://www.radioshack.com/enercell-12v-12ah-sla-battery-w-f2-terminal-250-tabs/2301219.html#.VOMhrHvRXdEThe Desulfator I am using has a very narrow duty cycle, <0.01%. It works by using the battery voltage as a power source, hence why I put another 12V in parallel, and may be a fault in the plan.The only number that looks like a date code says 12/10, if I am interpreting right. Seeing how dead it is, 5 years old is believable.So far, after two days the results are disappointing. The OC voltage is now 0.05V--hardly any effect at all. Part of the problem may be the 12V battery I have in parallel to power the desulphator, may be sapping any effect.If I get no further improvement in another day, I will try Circlotron's method of applying reverse voltage for a bit. Out-of-the-box thinking may be needed here.

author: Muttley Snickers
author_rank: Unknown
timestamp: February 17, 2015, 01:12:04 pm
content: The date code of 12/10 will most probably be YY/MM so October 2012, I'm on the fence with this particular one, but out in the field we don't give these any longer than 3 years unless it's a Yuasa or Sonnenschein which can still be ok after 5 years, dependent on installed system.Cheap nasty brands like Neuton Power would be lucky to last 2 years and your's I suspect will be similar. Also some UPS's tend to cook these batteries and shorten their life. But just a note, I have never bothered to give one resuscitation, we just let them die in peace, the poor old souls, zombie batteries scare the hell out of me and my systems.

author: Seekonk
author_rank: Super Contributor
timestamp: February 17, 2015, 02:53:38 pm
content: If you place two batteries in parallel, I would place a good size inductor (like a 12V secondary of a transformer) between the two. That would keep the pulses on the defective battery.

author: eneuro
author_rank: Super Contributor
timestamp: February 17, 2015, 04:04:00 pm
content: Quote from: TheRuler8510 on February 17, 2015, 11:53:51 amDid you checked scope waveforms etc to see how this desulfator waveform on battery terminals looks like and which is Vmax on battery during desulfation when this pulse hit its terminals?Even without scope it can be done using fast 1N4148 diode and small cap in parallel to battery with hihg resistance multimeter and on bad battery those voltage spikes will be higher and during desulfation this voltage should go down....while internal resistance of repaired battery should improove and be lower than before desulfation...Really you have 0.01% duty cycle?Which is operating frequency of this "desulfator"?I willmy desulfator tomorow while from time to time trying to improve software in my prototype battery charger, so will try two different batteries-old VARTA L2 12V 640A and new one VARTA Silver to see how those desulfator voltage spikes differ on brand new battery and probably much more sulfated 7 years old VARTA L2

author: Fraser
author_rank: Super Contributor
timestamp: February 17, 2015, 04:20:53 pm
content: I know this is really just an experiment on recovery of a possibly 'dormant' battery, been there done that, but if the OP had been in the UK I would have saved him any possible disappointment and sent him a replacement at cost of postage only. I have several brand new Yuasa 12V 17Ah and 12v 38Ah batteries in my garage that are in A1 condition. I always like to have some in stock in case of need but give them a top-up charge every 3 months as recommended by the manufacturer.I have absolutely no issue with people trying to resurrect sulphated batteries but from a commercial point of view, time is money and they are just not worth the time or effort and can never truly be trusted even if they appear to 'recover'.As a side note, I also look after my cars batteries and it shows in the life that I get out of them. We do a lot of short trips, often with headlights on and rear screen heater running in the winter. The poor batteries have a hard life as a result as the starting charge is not recovered on each journey. I tend to 'top-up' the charge every couple of months. My Audi and my Wife's Nissan are still on their original batteries and both cars are from 2005. 9/10 years out of a car battery is easy to achieve if the battery is a quality product and looked after. Some owners just hammer the battery in this age of little or no maintenance and then wonder why they need a new car battery every 3 or 4 years, sometimes less. At the end of the day, it is personal choice. I am a electronics and communications engineer (in UK terms) and still believe in preventative maintenance, where appropriate. Some preventative maintenance can do more harm than good but that is another story.I have just bought two new batteries for our cars, not because the old ones are shot, but purely due to preventative maintenance....why risk a complete failure and resultant stranding when the battery has obviously had a long service life (approx 10 years) and is due for replacement on those grounds alone. The old batteries will be looked after and likely gifted to someone in need of a spare or temporary replacement. The new batteries are from a local car parts supplier (Halfords UK) and are made by Yuasa, a quality brand, and they are decent batteries for around GBP60 each. Risking a complete battery failure for GBP60 would be considered foolish, hence the application of common sense. The old batteries owe me nothingAs a student way back in 1985-7 things were very different. I had a 1971 Mk1 Ford Escort (wish I had kept it) battery charging systems were not as refined as these days and the Escort had a D.C. Dynamo as the charge generator. The battery was so knackered that if the engine did not fire in less than about 10 turns the battery was flat ! I nursed that old battery for two years before finally giving in to the obvious. It was time to replace it. I had resorted to keeping the battery on charge overnight during Winter and warming the spark plugs to get it to fire up on a very cold morning with thick oil in the sump. Extreme measures, but when you do not have the money for a new car battery, you have to improvise. These days I can't believe I went so far to keep the old decrepit battery going......I doubt any modern student would do such and may even consider me crazy. Times change !So when people talk about looking after Pb based batteries and recovering them from the dead, I know what you are thinking.... been there, done that, got the T shirtI wish the OP well in his valiant endeavours to breath life back into the sulphated battery.....but please do not be too disappointed if/when you fail in that objective. As has already been said....maybe it will just be a case of letting it rest in peaceAurora

author: tautech
author_rank: Super Contributor
timestamp: February 17, 2015, 06:52:36 pm
content: Quote from: 3roomlab on February 17, 2015, 12:27:27 pmI wonder too.This is interesting info and obviously based on trial and error.The results speak for themselves.

author: tautech
author_rank: Super Contributor
timestamp: February 17, 2015, 07:43:40 pm
content: Quote from: eneuro on February 16, 2015, 11:15:04 pmYes the schematic is a long copied one.See how the Fet when on supplies a current into what appears to be a short circuit but the inductors absorb the current until they saturate.This is where the duty time iscritical, they must not be allowed to saturate. Fet on time controls this and at turn off the released back EMF from the inductors collapsing field does the desulphating.The greatest gains of this circuit are made with custom inductors andto duty cycles.A scope Current probe becomes very handy to monitor for saturation and measure the ouput pulse improvements.

author: eneuro
author_rank: Super Contributor
timestamp: February 17, 2015, 09:41:17 pm
content: Quote from: tautech on February 17, 2015, 07:43:40 pmMaybe this analog circuit with 555 needs some trickyto get it working, so of course never wasted my time to mess with its internals, however made of course simulation of this circuit in software to see how it worksIn my car battery charger I can easy update in software desulfator mode simply by limiting maximum PWM duty cycle to lets say between 1% -5% @ 10kHz PWM with bypassed inductor.Just looking into its AVR code and probably will have to ensure that battery voltage measurements are made when there is no desulfator spikes, so this charger itself will keep batery at safe floating voltage 13.5V-13.8V in desulfator mode, while sometimes desulfator spikes can have too small total energy to keep desulfated battery voltage at floating voltage, so if battery voltage in desulfator mode will drop below 13.2V it will automatically increase maximum PWM to 50% to reach floating voltage 13.5V (switch to standby mode) and then return back to desulfator mode with decreased maximum allowed PWM duty <<10% .This way power consumption to perform desulfator mode should be very low while duty cycle will be limited to 1%-5% so @ 24Vmax and it costs not so much kWh even during a few months of desulfation mixed with keeping battery at full charge at floating voltageUpdate: Probably will add AC mosfets switch to make automatic bypassing of inductor and slightly limit spike currents to levels safe for battery.This is another interesting question-what optimum maximum desulfation spike current might be for 60Ah-70Ah 12V lead-acid battery?

author: tautech
author_rank: Super Contributor
timestamp: February 18, 2015, 01:20:11 am
content: Quote from: eneuro on February 17, 2015, 09:41:17 pmThe 555 circuit IIRC only produced 2-3 Amp pulses @ 30 V and any reasonable variant will work to some degree.With some tweaking and a custom 220uH inductor that can be doubled or more.Power cosumption was never an issue the std desulphater as battery capacity and OC voltage increased while in use.This is the desired result,but how can that be observed when you charge at the same time.As for good sized starting batteries, the more I could give them the better/faster the result.I remember spotting a mains powered unit that IMO was a "kill or cure" method as the output was so large.If I had any LA battery that measured under 10V results were poor.Sometimes a top up charge followed with rest to stabilize voltage, then desulphate might bring them back, the key indicator was the OC voltage rise after desulphation.While only tenths of a volt, it indicates battery improvement as the internal chemistry changes even though the desulphator consumes current.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 18, 2015, 06:29:47 am
content: The beauty of the dimmer based desulfator is that you could change the strength of the pulses by changing the size of the capacitor. For a typical car type battery, use a 10uF or so motor run cap. (On 120V mains at least - halve capacitor values for 240V mains.)A variant on this is to get rid of the dimmer (so now it's just a bridge rectifier with a series cap connected to the mains) and replace it with a SCR and some sort of voltage based trigger circuit in series with the output. That can help if you're dealing with big batteries that require too much current for a common light dimmer to handle. A further variant is to change the bridge rectifier to a single diode so that the cap gets charged to the peak of the mains voltage on the negative half cycle, followed by the SCR triggering near the peak of the positive half cycle.

author: eneuro
author_rank: Super Contributor
timestamp: February 18, 2015, 08:12:45 am
content: Quote from: tautech on February 18, 2015, 01:20:11 amTrick is this charger is powered from charged battery itself, so I can monitor its voltage all the timeAdditionally its controll circuit without LCD display etc has such low power consumption that its power supply current is limited by 100 Ohm resistor and 24Vz Zener trying to protect LDO LM2940T 5V on its inputs.Bigger concern is if those spikes are not consumed in charger PSU while it sits on battery, but while even sulfated battery has much lower internal resistance and lower voltage accross battery those spikes should hit battery most of the time.Quote from: NiHaoMike on February 18, 2015, 06:29:47 amWith MPU on PCB its better keep full bridge reactifier and measure input voltage on capacitors after full bridge and when it falls below given level (eg. 24V) than switch off PWM and wait in software for proper voltage, so with 250kHz ADC clock and 13 clock per ADC measurement one can monitor this voltage close to 20000 times per second.Probably will make another MPU based desulfator with support for many batteries at the same time with simply optoisolated voltage feedback when battery voltage reaches 13.5V to have some kind of overvoltage protection and be able to keep all those desulfated batteries at safe floating 13.5V-13.8V voltage

author: oldway
author_rank: Super Contributor
timestamp: February 18, 2015, 12:00:27 pm
content: All those little battery desulfators does not work at all.http://www.sotolab.eu/eng/products.htmlThis is something more serious !I recomand first to try to recharge the battery with a 50/60V dc power supply with a 110V/100W bulb in serie.When voltage on battery drop at about 12V, you can try to recharge it with a battery charger.

author: eneuro
author_rank: Super Contributor
timestamp: February 18, 2015, 04:02:25 pm
content: Quote from: oldway on February 18, 2015, 12:00:27 pmIn general company with "LAB" in name smells always for the first time like bullshit before you verify their claimsIn this blogCar Battery Recovery (Desulfation)someone reports another desulfator working at 10kHz and claims it worked for him.http://thegreatgeekery.blogspot.com/2013/06/car-battery-recovery-desulfation.htmlUsed desulfator there, but who knows maybe this blog was made by... manufacturer of this cheap thing:http://www.aliexpress.com/item/Free-shipping-Auto-Pulser-Desulfator-for-lead-acid-batteries-battery-regenerator-battery-reviver-battery-rejuverator/608796702.htmlSo, its sometimes better reuse a few spare elements and make own DIY desulfator with own MPU source code which we can tweak when want to make research and need to implement feature which is not available in thosemagic desulfatorsI have 24VAC secondary transformer so @ ~35Vmax will see what happends when on peak voltages after bridge with a few caps in parallel we'll try 10kHz PWM when those peaks are detected on MPU ADCQuote from: oldway on February 18, 2015, 12:00:27 pmYep it is good idea, so simply such light bulb bypassed by mosfets switch might work to precharge battery to voltage where desulfator mode can be usedThe only thing left to design is battery monitor on its terminals but switchable, so we could detect and check for undervoltage or overvoltages in time where desulfator PWM is off and light bulb or other current limiting device disconnected as well

author: SArepairman
author_rank: Frequent Contributor
timestamp: February 18, 2015, 07:09:08 pm
content: I hate how there is no concrete evidence of desulfators.I kinda wanna do desulfator testing complete with autopsys and microscope slides.I have two SLA's that are both pretty dead. Does anyone have some kind of experiment in mind that will be easy to implement?I feel like without actually getting some (magnified) pictures of the lead plates this is a bunch of voodoo.I have tried to recharge a SLA before that I refilled with water, I got maybe 25% capacity out of it. I kinda wanted to try building a desulfating circuit, but it seems that people have like 50 different methods of doing it, duty cycles, wave shapes, peak currents, average currents... I felt like a cat trying to find a comfortable spot on a bed.If some kind of general consensus can be reached in this thread maybe I will solder / angle grind something.Some kind of single cell "test jig" made in a clear tank of acrylic perhaps? Carefully take apart a multiple cell SLA battery, do experiments on cells 1 by 1.'how feasible is this / can a general purpose test rig be built to cover the majority of desulfator concepts?

author: eneuro
author_rank: Super Contributor
timestamp: February 18, 2015, 07:56:20 pm
content: Quote from: SArepairman on February 18, 2015, 07:09:08 pmIf you follow another videos of this guy you'll find out that it uses this modifiedhttp://www.frontiersprings.com/desulfator.htmlcircut with bloody inductors and those videos was one of the best I found when was looking for this sort of things and starting point to make own MPU version.In this video he shows even some cells comparisions etc.Unfortunatelly, this time lapse cell video is made... without usage of tripod and... he shows cell images not centered in the middle but random position around the centre of the screenBetter than nothing, but... difficult to see differences, however idea not so bad.In other videos he showed trick with voltage spike measurement on desoldered battety using 1N4148 and 100nF cap in parallel to battery, so it might be worth to see how hethis circuit to work.Anyway, I do not know best desulfator circuit and its parameters, so it could be interesting look into details like PWM frequency, duty cycle, maximum voltage and peak currents if someone bought another one and see its teardownThose parameters are not included in "product" descriptions of those available to buy, so I see no reason to buy any of them and just makeing research to adjust those parameters in Made at Home desulfators, because of course without knowledge of physics behind this it is difficult to choose right ones based only on manufacturers claims who wants sell this sort of products...

author: Fraser
author_rank: Super Contributor
timestamp: February 18, 2015, 08:15:53 pm
content: http://leadacidbatterydesulfation.yuku.com/forums/1#.VOTyuOasWSo

author: eneuro
author_rank: Super Contributor
timestamp: February 18, 2015, 09:37:11 pm
content: Thanks for link to this forum, but it looks like all desulfators there are build around 555 without any mosfet gate drivers, etcThey says it bad idea pulsing batts in parallel, but... putting batts in parallel WITHOUT diodes which should prevent currents flaws between each other it is sometimes bad idea itself, so I do not buy it :http://leadacidbatterydesulfation.yuku.com/topic/1160/Pulsing-batts-in-parallel-is-a-bad-idea#.VOUB0qp7NQIMaybe should dig deeper on this forum to find more detailed specs of peak pulses they use, etc...Update, ok. 555 based voltage doubler sounds better while quite nice mosfet driver TC4426 is used...http://leadacidbatterydesulfation.yuku.com/topic/1193/Voltage-Doubler-Desulfator-Design#.VOUGlap7NQIand ... proof of concept from this post above , but ok, there are some scope waveforms so not so badHowever, why 40Vds 200A 0.004 Ohmhttp://www.irf.com/product-info/datasheets/data/irf1404.pdfwas used there?

author: SArepairman
author_rank: Frequent Contributor
timestamp: February 18, 2015, 09:39:52 pm
content: well a BJT 555 timer can drive a fair bit, the CMOS version substantially less.

author: TheRuler8510
author_rank: Regular Contributor
timestamp: February 19, 2015, 12:09:43 am
content: Update to my science Experiment:After putting in an inductor in series with the parallel battery as suggested by Seekonk, I get much better pulses into the dead battery. Using my scope and a high voltage differential probe, I can see the pulses squared up nicely and are actually a duty cycle of 0.27%, or pulse width or 2 usec at 1.3 KHz. Pulses are 116V in amplitude.Anyhow, after running a day that way, the voltage is still only at 0.05V, so I decided to run the reverse voltage thru the battery as suggested by Circlotron. Plan is 2-3 days that way, then reverse the voltage to normal.

author: Circlotron
author_rank: Super Contributor
timestamp: February 19, 2015, 04:47:02 am
content: Quote from: TheRuler8510 on February 19, 2015, 12:09:43 amMake sure you limit the current to 2% of Ah capacity. Don't try to speed it up with more current!!!

author: eneuro
author_rank: Super Contributor
timestamp: February 19, 2015, 07:02:38 am
content: Quote from: Seekonk on February 17, 2015, 02:53:38 pmDo you mean something like classic boost switching converter like this below where Vin is our power source and on Vout our sulfated battery in place of output capacitor?Boost Switching Converter Design EquationsIf we haven't got higher voltage source it's quite easy way to boost it up, so I wonder why guys in Double Voltage desulfator linked above tried hard to double up this voltage using caps?

author: Seekonk
author_rank: Super Contributor
timestamp: February 19, 2015, 01:35:27 pm
content: NO, not at all. A desulfinator has to have a power source to work. If you notice many of these circuits have two inductors. The first isolated the battery (and therefore the pulse) and charges the capacitor that provides current to the second inductor that provides the pulse. This is because some batteries may not be able to supply enough current to that inductor. When a second parallel battery (or even a charger) is used to supply the voltage, that battery should be isolated from the pulse by an inductor to maximize the pulse into the sulfated battery. I believe in the posted picture, the large capacitor is used a load to simulate the battery so current can be measured by the Pearson CT. A battery is a large capacitor.

author: TheRuler8510
author_rank: Regular Contributor
timestamp: February 19, 2015, 01:37:54 pm
content: Quote from: Muttley Snickers on February 17, 2015, 01:12:04 pmI misquoted the date code; exactly as written says, "1218 10". It is branded into the plastic, and I am still assuming it is a date code.

author: TheRuler8510
author_rank: Regular Contributor
timestamp: February 19, 2015, 01:58:46 pm
content: Quote from: Circlotron on February 15, 2015, 09:51:50 pmCirclotron,Yes I have the limit set to 190 mA, or 1.6% of AH rating.How high in (reverse) voltage should I go? I have it limited to 13V right now, and it is drawing less than 1 mA.Thanks,

author: oldway
author_rank: Super Contributor
timestamp: February 19, 2015, 02:08:03 pm
content: A fully discharged battery has a very high internal resistance.For this reason, you must first let react the most PbSO4 possible.You need a high voltage with current limiting to begin to recharge the battery.When voltage on battery drops nearby the nominal voltage, you can try to desulfate the battery.It works really, it has been proven: see test here: (in french)http://www.batterie-plus.fr/images/pdf/rapportLCIE.pdfHow works the regenerator ?With high energy pulses of 300A during 200ms and 3s interval time. (for car batteries, this is reduced to 50A pulses)See page 18 of BRT203.http://www.batterie-plus.fr/PDF/manuelutilisationbrt203.pdfOther models:http://www.batterie-plus.fr/ventederegenerateurs.aspx

author: eneuro
author_rank: Super Contributor
timestamp: February 19, 2015, 03:19:31 pm
content: Quote from: Seekonk on February 19, 2015, 01:35:27 pmFast diode can easy be rated for hundreds of amperes in pulse.Anyway what is wrong with boost converter powered from transformer or other battery?We could make bypass on diode with a few low RDSON mosfets in parallel and switch them on to bypass diode (fro higher efficiency) when switching off main boost converter bottom switch and huge voltage spike should hit sulfated battery...

author: Seekonk
author_rank: Super Contributor
timestamp: February 19, 2015, 04:00:33 pm
content: Your reply seems totally unrelated to anything I have said. These devices are foolishness.

author: eneuro
author_rank: Super Contributor
timestamp: February 19, 2015, 05:34:49 pm
content: Quote from: Seekonk on February 19, 2015, 04:00:33 pmWhich devices?If you draw or provided any circuit schematics with your idea of indudctor between power source battery and this sulfated, than everything could be clear.In links with this Double Voltage desulfator people in that thread made also circuit simulation and they got quite similar results with real experimentTo discus circuits we need a schematics-it is easier to understand and visualise concepts.So, simply circuit schematics idea or photo is worth more than thousands wordsAnyway, programmed small H-bridge to drive GDT @ 10kHz PWM and pulse GDT at <5% duty cycle to drive AC mosfets switch which succesfully trigered thyrystors in anti parallel (SCR's) to switch 230VAC mains load.Probably will try use this 1000V AC mosfets switch to drive inductor in boost converter and will see if I will get high voltage spikes on desulfated battery using classic boost converter shown aboveUpdate: Ready for real experiment -boost mode in custom charger with two ideal diode drivers should create nice voltage spikes on batteryMaybe its timing or energy will not be perfect for desulfation, but worth to try-I need boost mode in my charger after upgrade anyway, so good time to add this feature and change slightly buck converter and make it more versatile

author: eneuro
author_rank: Super Contributor
timestamp: February 19, 2015, 05:58:08 pm
content: Quote from: TheRuler8510 on February 19, 2015, 12:09:43 amCould you post a photo how this bloody inductor is driven in your circuit, because of I can imagine inductor whcih connects two batteries eg. on its (+) terminals, so it is in series, but... it must be sosme kind of current limit-how do you drive this thing and how it looks like?Maybe, I missed something or simply too many lines of MPU code written today

author: Circlotron
author_rank: Super Contributor
timestamp: February 20, 2015, 02:06:33 am
content: Quote from: TheRuler8510 on February 19, 2015, 01:58:46 pmI seem to remember it was about the same as normal charging voltage, 13.65 for a SLA, 14.1 for a car battery. I never tried it on a car battery though.

author: oldway
author_rank: Super Contributor
timestamp: February 20, 2015, 11:39:44 am
content: I did some desulfation testing on an old 50ah car battery that had loosed more than two third of its capacity.I used 50A peak current pulses of 200 ms with a 4s interval.Results: after a few hours, the battery has completely lost its capacity ... totally dead!But there are so many causes of battery failure, other than being sulfated, especially for automotives batteries which are subject to vibrations and high starting currents, that we can not draw conclusions about a single trial.In any case, I am convinced that small low-energy fixtures do not work at all and it's a scam on the part of those who sell them.I am still waiting to see the reports of official tests done by honest firms to be convinced otherwise.Explanations of vibrations of crystals that come into resonance at breaking point has no scientific basis, it is more like alchemy than science fact.Whoever has a bit of scientific knowledge can not believe in such nonsense.

author: eneuro
author_rank: Super Contributor
timestamp: February 20, 2015, 02:09:24 pm
content: Quote from: oldway on February 20, 2015, 11:39:44 amI do not like idea of 0.2s huge amps pulses.Just modified this simple voltage doubler circuit from linked thread above to be able use power supply in parallel with sulfated battery:Between short HV pulses we can precharge battery with current limit schown as light bulb in this simple circuit simulation.Battery is not drawn there but it is right part of this circuit and from sulfated battery side no diode needed-right capacitor is charged to sulfated battery voltage, so we need first use other tricks or HV via light bulb to try put dead battery above 10.5V before switch to desulfator pulses mode.Anyway, thanks to this circuit design we can use HV power supply to NOT DOUBLE battery VOLTAGE like in its oryginal design from links above but... step up to pulse which can be much higher than desulfated battery voltage-while turning on the switch creates voltage spike equal to power supply Vmax (left part)Now its time create small PCB, solder a few caps in parallel instead of one bulky 6800uF, fast diodes, two small inductors and connect to 24VAC transformer secondary left part and to suspect dead battery with high internal resistance on right side, attach preprogrammed GDT mosfet driver or another of our choice to create those pulses on battery by turning on.off switch in the middleOryginal Mark voltage doubler desulfator circuit concept there:Someone sells this Mark capacitors desulfator as a kit:http://www.courtiestown.co.uk/index.php/battery-desulphators/kits/12-24v-voltage-doubler-desulphator-desulfator-kit.htmlThis is image of components from this oryginal voltage doubler kit above:However, I prefere own mosfet drivers and change a few lines of code in AVR to change pulses PWM and duty cycle, so 555 not interesting option anymoreOnly a few elements if we have mosfets driver, no need to mess with 555 no moreThanks @Aurora for link to this interesting forum

author: Seekonk
author_rank: Super Contributor
timestamp: February 20, 2015, 02:14:28 pm
content: Stick to writing softwarehttps://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif

author: oldway
author_rank: Super Contributor
timestamp: February 20, 2015, 02:54:19 pm
content: @eneuro: My experiments (pulses of 200ms 50A with 3 or 4s interval) has been done on basis of a comercial aplication who is working.It has been proven by official tests.(See my links in my previous post.)Before you make an electronic project, you would first understand on what principle the electric desulfation works.Principle of resonating PbSO4 cristais and break them is bullshit.1) it's not proven than PbSO4 have some piezoelectric caracteristics. Vibration is a mecanical effect of piezoelectric caracteristics.2) PbSO4 cristais are of different shapes and dimensions and would then resonate on different frequencies.3) To resonate at a high amplitude, a piezoelectric cristal need a sustained oscilating electric field, not only a pulse. (only damped oscillations)4) electric field is very low : if you measure voltage on the battery terminals with a scope, you will see that you don't have high voltage pulse as soon as there is a little quantity of PbSO4 who has reacted. (internal resistance became very low)For this reason, you need high energy pulses, what your circuit is not able to produce.5) With low electric field, it's almost impossible to break a cristal....I never seen a cristal ocillator broken only by low oscillator voltage.Your circuit definitively will not work for desulfating bateries, you waste your time and your money.

author: eneuro
author_rank: Super Contributor
timestamp: February 20, 2015, 06:31:08 pm
content: Quote from: oldway on February 20, 2015, 02:54:19 pmUnfortunatelly, French is not my technical language, but really nice images and looks like a cool stuff-will try find something similar in EnglishAnyway, the more people will research and try, sometimes discoveries are made ... by chanceI know, that it is not easy to solve a puzzle if you never seen complete image before, but common-I do not loose my time watching stupid TV channels, so a few hours for something like this it is a fun to see what happends and maybe I'll be able get similar results like people from that voltage doubler desulfator thread-for the moment just from point of view current spikes and energy achived, etc.Quote from: oldway on February 20, 2015, 02:54:19 pmWhen was designing my aluminium anodizing equipment, current needed was proportional to aluminium plates square area:http://www.anodizeusa.com/pas23.php"In the anodizing industry using amps per square foot anodizing has always been considered the fastest and most accurate way of anodizing parts for a quality minded customer."My guess is, those pulses current might be also dependent on battery used and bigger battery has higher plates area, so much higher currents needed for bigger battery?50A in the case of 50Ah battery doesn't looks like a monster current like 200A, but 0.2s is a lot of time, so this timing looks strange, but ok, maybe it is needed.How much energy in your experiment your 50A pulse had?If we had resistance or voltage to calculate power than, energy or work:W=P*twhereP=R*I^2=V*I=V^2/RIsn't sulfated battery internal resistance important and amout of this desulfator pulse energy calculated based on this parameter?Quote from: oldway on February 20, 2015, 02:54:19 pmThis circuit was derived from other people work and it is still a concept not simulated inSpicebutFalstadjust to have some idea what to expect and whether I smell cooked ICs and see flying around capacitors or there is some hope that if it won't work I'll be able reuse components in another project and they survive

author: eneuro
author_rank: Super Contributor
timestamp: February 20, 2015, 06:47:23 pm
content: Quote from: Seekonk on February 20, 2015, 02:14:28 pmIt is easier write software if you made also PCB, so my desulfator soft is ready and can't wait for PCB to check it outBTW: Electrons doesn't care if PCB and elements were soldered by EE or software engineerQuote

author: oldway
author_rank: Super Contributor
timestamp: February 20, 2015, 08:17:59 pm
content: To understand how works desulfation of acid lead batteries, we have first to know how battery sulfation occurs.Sulfation is a normal process during battery discharge and is almost fully reversible.Sulfuric acid (H2SO4) of the electrolyte participate to the reaction and when battery is fully discharged, almost all the sulphuric acid has reacted with PbO2 and Pb to produce PbSO4.The internal resistance of the battery became then very high (water is not a good conductor of electricity and PbSO4 on the negative plates acts as insulation)For this reason, battery does not accept charge current any more and seems to be damaged.But that is not allways the case.Current flows, but is very low because the internal resistance is too high.For reversing the reaction, whe need to let flow a greater current by increasing recharge voltage.With 50V for example (12v nominal battery), whe succeeds initiate the reverse reaction (2PbSO4+2H2O --->2H2SO4+PbO+Pb) in a few tens of minutes.The concentration of H2SO4 increases and the internal resistance of the battery decreases.If current is limited, voltage upon terminals of the battery drops than to 12V.Battery may now be charged with a commun battery charger.In normal situation, battery is never fully discharged. (60 to 80% max.)Reversing the reaction is then easy but is never 100% completed.For this reason, the battery loses his capacity in normal use.To prevent such a sulfation, manufacturers recomands to overcharge the battery one time a week .But this is only possible with flooded batteries.The battery desulfators are intended to restore a part of the lost capacity.Some explanations about my 200ms 50A pulse generator:I used a 24V 30A battery charger with triac control in the primary.Conduction angle was ajusted for 50A peak and conduction time controled by an ajustable NE555 oscillator.The current must be high peak value and the pulse duration must be long enough to create a high voltage drop and to let flow a sufficient average current to make the dissolved PbSO4 react.But power dissipation in the battery is high because waveform give high rms values of current.For this reason, pulses have a 3 or 4s interval for not exceeding the maximum temperature of electrolyte.

author: tautech
author_rank: Super Contributor
timestamp: February 20, 2015, 10:01:48 pm
content: When I started looking at this ~20 yrs ago, there was only 1 website devoted to the principle of LA battery desulphation. For the life of me I can't find it ATM, it will be in one of my old archived HD's.At the time IIRC it was based on a patent that was then explored to asses the science behind it.Sulphation is a normal part of the charge-discharge process, it being reduced with charging as the sulpher is transfered back into the electrolyte, that then increases the SG.Yep basic stuff.But as a battery ages it's capacity reduces, WHY?There was discussion of the sulpher bonds that form on the plates, that in time reduces the available plate area and reduces battery capacity.These sulpher bonds are of some complexity, the simplist removed by just charging.Others levels of bonds can be reduced with an OV charge of 15V or more.The remaing are what Desulphation addresses.This is not simple science, there are so many factors that affect battery life, the natural ageing process through use being only one of them.Attempts to recover failing batteries bring mixed results and IME desulphation is best applied as a maintenence measure to extend battery life.For the doubters:A self powered desulphator WILL increase OC battery voltage after a period of application.EVEN THOUGH THE DESULPHATOR HAS CONSUMED CURRENT FROM THE BATTERY.AND battery electrolyte SG WILL rise also.Now tell me it's

author: eneuro
author_rank: Super Contributor
timestamp: February 20, 2015, 10:11:52 pm
content: Quote from: oldway on February 20, 2015, 08:17:59 pmA lot of usefull informations about maintenance of lead acid batteries also can be found herePDF: Storage battery maintenance and principlesQuote from: oldway on February 20, 2015, 08:17:59 pmHow long time those pulses were applied?Even with a few seconds interval if internal resistance of battery will be lets say 200 mOhm, than at 30A rms we have average 0.2s pulses energy about 180 Wats *0.2s / 4s =9 W.Need estimate this and compare with those "crappy" 555 based desulfatorsPeople reported 30A pulses in their voltage doubler desulfator adn yes they were short, but some of desulfators available at about $30 had operating frequency 10kHz- 2500 times more pulses per second than 0.2sTon of 4s period.Anyway, thank you for some description of your setup and hints to dig into internals of those commercial available desulfators.BTW: One desulfated battery (more than 7 years old VARTA L2 (640A oryginal)) using old shorted inductor in buck converter method as "desulfator" described somewhere above, was not able start 1.4 HDI diesel at 0*C temperature, but with another old battery in parallel (matched using resistor -light bulb-and fully recharged before connection) easy started this engine, so it clear they are not complettly dead, but simply such single car starter battery can not start this diesel car and unfortunatelly there is no space to put two-three such batteries in parallel, so yep brand new VARTA silver was needed, but I use this old car battery in my lab as low power supply and it is still usableWe'll see what happends when this new desulfator will be connected for a few months with small discharges during the day and desulfation during the night at its floating voltage 13.5V

author: oldway
author_rank: Super Contributor
timestamp: February 21, 2015, 11:25:34 am
content: QuoteA 50A peak 200ms current pulse with no current during 4s (T=4.2s), that's:Iav = (50 x 0.2)/ 4.2 = 2.38Aav. (average value = charging current)Irms= 50 square root of (0.2/4.2) = 10.91ArmsPower dissipated in the battery (200mOhm internal resistance) = 0.2 x (10.91)² = 23.81WSee current pulses of the industrial desulfator BRT 20-2 of "BATTERIE plus".

author: eneuro
author_rank: Super Contributor
timestamp: February 21, 2015, 02:46:33 pm
content: Quote from: oldway on February 21, 2015, 11:25:34 amYep, I forgot that period is not 4s, but 4.2s, but we'll get similar result for... 10kHz pluses and 5us Ton, while 0.2s/4.2s~5% duty cycle and @ 10kHz period is 0.0001s with 5us ON time we get 5% duty cycle too, which means the same amount of power is neededP(T)=0.2Ohm*(50A)²= 500 [J/s] @ 5% duty cycle we get:500*0.05=25W500W*0.2s/4.2s= 500W*0.0476 ~ 23.8W (the same what you get).It is interesting that from power point of view pulses 0.2s @ 0.4Hz and 5us @ 10kHz have similar total pulses energy in given time

author: oldway
author_rank: Super Contributor
timestamp: February 21, 2015, 04:12:23 pm
content: You forget the rise and fall times....With 5µs pulse time, they are not negligible any more.And your 10khz oscillator would have to produce 50A pulses...not that easy !(with a lot of RF...!)Working with low frequency is far more easy.I think that's the reason why industrial desulfators works of this manner.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 21, 2015, 04:32:19 pm
content: A big MOSFET can do that quite easily. But for large batteries, high power SCRs are easier to come by. Aside from the dimmer based circuit I suggested earlier, maybe it's also possible to use a strobe light with the battery connected in series with the flash tube.

author: oldway
author_rank: Super Contributor
timestamp: February 21, 2015, 05:28:15 pm
content: Another manufacturer of industrial desulfators (Energic Plus) use pulses of 150Hz. (probably from 3 phases 50Hz)http://www.energicplus.com/en/news/battery-regeneration-demonstration

author: eneuro
author_rank: Super Contributor
timestamp: February 21, 2015, 06:02:43 pm
content: Quote from: oldway on February 21, 2015, 04:12:23 pmNope, I didn't forget but assumed this calculation is estimation only of not exact pulse energy amount, but rather magnitudes, just to see if is it 10x times bigger or lower in the case of 10kHz 5% duty cycle in comparision to those low frequency desulfation methods.When we make more pesymistic asumption that those current pulses will be not square, but closer to triange, thanIrms= 0.577*Ipeak, so with Ipeak=50A we get Irms~29A.While pulse energy is proportional to I^2, so we have 29^2/50^2= 0.3364 ~1/3 of energyof square pulse with Ipeak=50A.It was about 25W @ 10KHz and 5% dyty cycle, so we get ~8W which is not so bad and not 10x lower but only 3x lower than 5% @ 0.25Hz in example commercial desulfator you showedBTW: Custom PCB with my modified voltage doubler desulfator concept is ready to solder elements, so next week it will be fun to play with real circuit not simulation

author: oldway
author_rank: Super Contributor
timestamp: February 21, 2015, 08:28:33 pm
content: I show you several industrial solutions that are really working.It's not easy to find informations about this, it seems to be "secret of manufacturer".I had a lot of links about it in France but they are all dead now.For automotive batteries, it seems that regeneration don't work.Not only because those little desulfators don't work (and in my opinion, that's the case) but also because plates of those batteries are too thin and they are damaged by corrosion before they have problem of sulfation. (this occurs normally after 4 or 5 years of use)

author: electrodacus
author_rank: Super Contributor
timestamp: February 22, 2015, 12:27:56 am
content: Lead Acid batteries are a waste of time and money.I almost see them as a lemon and nail type of batteryI have already 2 years of full OffGrid living and that will have been a nightmare with Lead Acid.I hope a day will come soon when you will only see Lead Acid batteries in a museum.

author: tautech
author_rank: Super Contributor
timestamp: February 22, 2015, 12:33:20 am
content: Quote from: electrodacus on February 22, 2015, 12:27:56 amPlease share yourcompletesolution.

author: electrodacus
author_rank: Super Contributor
timestamp: February 22, 2015, 12:50:06 am
content: Quote from: tautech on February 22, 2015, 12:33:20 amFor OffGrid energy storage I have a complete solution since that is what I was interested in you can search for Solar BMS I have a model that I use now SBMS4080 (I had a kickstarter for that last year) and I will in less than two days have a Kickstarter for a newer model.Because of this it my look like I have an invested interest but you are free to check all my claims. The project is also open source so anyone can make his own version.I use LiFePO4 since that is the best for stationary energy storage at this moment but Solar BMS supports any type of Lithium battery.Here is a photo with the complete solutionAnd here is a 7 day graph with my house energy production / consumption data logged with the SBMS4080 you can find the raw .csv on my websitehttp://electrodacus.com/

author: eneuro
author_rank: Super Contributor
timestamp: February 22, 2015, 07:25:24 am
content: Quote from: electrodacus on February 22, 2015, 12:50:06 amYour energy graph iscos(x)where x is angle between PV panels surface normal and sun rays, so using 2 axis sun tracker 30% more energy can be taken from the sunThis is from my sun tracker software, based onBird Clear SkymodelSUN is: 2015-02-22.303 07:16:01 UTC (2457075.803 JD) lat: 50.***N lon: -21.*E Sun hour azimuth: 54.109 Sun (geo) azimuth: 125.891Sun elevation: 13.644SunCSP power: 624.5 W/m2Day of the year: 53

author: eneuro
author_rank: Super Contributor
timestamp: February 22, 2015, 07:42:29 am
content: Quote from: oldway on February 21, 2015, 08:28:33 pmNanopulserreveals his secrets10kHz frequency and... 20mA-50mA power consumption ONLY with half meter wires each, sits on car battery not disconnected from car electronics, I guessBut sometimes (from Nanopulser linked video marketing spam)

author: Rerouter
author_rank: Super Contributor
timestamp: February 22, 2015, 08:41:43 am
content: at-least if anything from this thread i have learned that relying on an undersized lead acid can mean that it lasts longer, as it is properly cycled up and down, (solar pump off a 7.2AH battery).i'm guessing that the easiest way to figure out a batteries ESR would be to measure its voltage when a load is on vs a load off, if so could maybe hook up a micro to log whether it improves or gets worse on my 3 year old batteries,

author: oldway
author_rank: Super Contributor
timestamp: February 22, 2015, 11:42:22 am
content: I am still waiting for some scientific tests proving that such a little desulfator really works.Personaly, I don't believe it, nor that "anything is possible"Easier way to measure internal resistance of a battery:http://www.farnell.com/datasheets/1842852.pdfESD meter who accept dc input voltage without damage works also well.

author: electrodacus
author_rank: Super Contributor
timestamp: February 22, 2015, 07:23:04 pm
content: Quote from: eneuro on February 22, 2015, 07:25:24 amThanks for the input.Tracking is obsolete in my opinion (especially for offgrid) and here is why:In offgrid you can not use all the available energy as you seen in my graph and I did my best to use as much as possible in those 7 days.You have a few bad months in winter and your system is usually designed for that so in summer you have even more wasted (unused) energy.Now here are the statistics for my locations for the 4 winter months with this 3x 240W PV panels.I can get in November 10.6% more with one axis tracking and 13.6% with two axis trackingDecember is 4.2% one axis and 11.2 two axisJanuary 6% and 12.9%February 16% and 19.3% (here I already have excess anyway without tracking)As you see in winter when I will need extra energy the most I can get 10% average more at best with tracking.Now I can get those 10% with the use of an additional 10% more PV panels that is 72W PV so about 72$ at 1$/Watt for PVCan you provide me with a tracking device including strong supports for 72$ that can last for 25 years and not be destroyed by an occasional 100 to 120km/h wind ?In summer I can get 30 to 50% more but I will have no use for it I have even without tracking a lot of excess.But say I was grid tie and can sell any excess to the grid and have a 30% average over a year advantage from tracking.30% is almost another 240W PV panel that cost 200 to 240$ so for this cost again can you provide me with a solid traking mechanism able to survive 25 years? (fixed PV panel will last at least that)So many other technologies become obsolete including MPPT, solar thermal and even large windows for thermal gain just to name some.They all worked at 5 or 10$/Watt PV panels but not now.

author: electrodacus
author_rank: Super Contributor
timestamp: February 22, 2015, 08:02:42 pm
content: Quote from: 3roomlab on February 22, 2015, 07:35:13 pmI will heat my house with PV so my PV array will be 12x larger that will only require for me a small battery for overnight storage since even in the worst cloudy day I can get as much power as I do now with the current array in a full sun day.And is not important on what I use that electricity since it will end up as heat anyway heating the house.

author: eneuro
author_rank: Super Contributor
timestamp: February 22, 2015, 10:15:44 pm
content: Quote from: oldway on February 22, 2015, 11:42:22 amDefinitely want to do this with additional microscope support when new desulfator will be ready.It could be nice observe one lead-acid cell during discharge, charge, desulfation and see howbattery plates changes after desulfation

author: eneuro
author_rank: Super Contributor
timestamp: February 22, 2015, 10:29:09 pm
content: Quote from: electrodacus on February 22, 2015, 07:23:04 pmI wouldn't like talk about offtopics there too much, but yes working and testing such sun tracking device while 3m in diameter parabolic mirrors dish for CSP thermal energy needs to be quite precise positioned to the sun-hopefully sun position on the sky is predicted many years ahead and only time and GPS position needed to adjust dish azimuth and elevation directly into the sun regardless sky is accidentally clouded or we have perfect clear sky and can also estimate amount of available sun energy.To make such things capable to survive huragans is rather mechanical design problem, not sun tracking electronics which can control different electric motors

author: electrodacus
author_rank: Super Contributor
timestamp: February 22, 2015, 11:16:34 pm
content: Quote from: eneuro on February 22, 2015, 10:29:09 pmNot sure what you want to say. The most expensive part in a solar tracking system is the mechanical part including al that support for rotating and the motor that should cost well in excess of 72$ for 3 panels each 1m x 1.7mYou do not need all of that for a fixed system and with 72$ you get that additional PV panel that will perform the same as tracking thus my point that solar tracking is obsolete at the current cost of PV.But yes this is off topic is just another example of obsolete technology as Lead Acid is for energy storage.

author: eneuro
author_rank: Super Contributor
timestamp: February 24, 2015, 09:08:55 am
content: Just assembling desulfator and thinking about putting there small transformer 1:1 ~100uH-1000uH instead of two independent inductors.I've got quite nice spikes in simulation, but it looks like when reverse output (from right battery side) than of course circuit works slightly different.Anyway in configuration like above (transformer in phase dot marked) decent spikes are created on right battery side, however probably it will not be possible create them at 10kHz and additional tunning of components values needed, so first run from 1kHz and increase to 10kHz with duty cycle from 1% to 5% and lets see what happendsUpdate: Little surface mount art (SMA) after dinner and desulfator has quite powerfull strong tracksWe do want brake those bloody crystals and prototype pcb now is ready for final assembly:Waiting for low RDSON mosfets to complete assembly according to the plan:No mercy forhttp://en.wikipedia.org/wiki/Lead%28II%29_sulfate(PBSO4)

author: TheRuler8510
author_rank: Regular Contributor
timestamp: February 28, 2015, 08:49:26 pm
content: Update:After a week or so of no results, i.e. no current flowing into the battery--not even microamps--I decided to crack open the battery and look inside. It was not easy since it is a sealed battery.I took one writer's advice in this thread, and add some water to each cell--about 2 eyedroppers full each cell--and presto, it is now taking current. I am keeping it to less than 100 mA for now while I see what happens. I cannot say if the desulphator had any effect during this phase or not--it may have been the water addition--but who knows...Remember I am doing this as a fun science experiment, although it would be nice to get some use out of it.

author: eneuro
author_rank: Super Contributor
timestamp: March 03, 2015, 09:32:51 pm
content: Quote from: TheRuler8510 on February 28, 2015, 08:49:26 pmRather basic, first thing is examine cells if battery is dead and add water if neededIf you have access to battery cells, you could use hydrometer to measure the specific gravity of the electrolyte from time to time.In this patent abstract translated from ChinaPortable storage battery electrolyte ultrasonic areometerThe invention is anultrasonic transducerusing a single acoustic wave propagation time measuring working electrolyte measured in pulse-echo mode.Quite interesting methodAnyway, I'm close to finish my new desulfator-had to wait for a few components.Soldered today two 100uH 2A inductors and assembled another AC mosfets switch, so circuit is ready to connect it to external galvanic insulated gate driver.We might need more caps in parallel, so maybe another similar PCB with caps only will allow easy increase capacitance.Two fans from top and bottom, radiators on mosfets drens and setup is almost finished for a few months night work

author: CatalinaWOW
author_rank: Super Contributor
timestamp: March 04, 2015, 01:00:25 am
content: Don't let OPs problem with the Radio Shack batteries turn you away from some smoking deals. Happened across a Radio Shack that was still open and closing out and got 3 7AH units for $12 each. When I got them home found all were good.

author: ReaDave
author_rank: Newbie
timestamp: March 04, 2015, 09:03:22 am
content: Hi everyone,Just found this forum and this topic which has me very interested, particularly the stuff about reverse charging SLAs at 2% to remove sulfation. I have a bunch of SLAs that were given to me by a friend who owns a security company. They replace the batteries in their client's alarm systems every year whether they need it or not and he gave me a bunch of the old ones which have been quite serviceable. Many of them now have significantly shorter AH capacity so I'm going to give this technique a shot and see what happens. Worst case scenario is that I gain nothing much. The batteries cost me nothing so any potential gain (pun intended) is a bonus.For those who are curious, I just posted a short introHEREalong with a little at the end about how I found this forum.This looks to be a very cool place for a fellow electronics geek!!

author: ReaDave
author_rank: Newbie
timestamp: March 04, 2015, 12:30:01 pm
content: I've just set up an LM317 current limiter running from a 12 volt unregulated plugpack (no load is about 16 v) and even with quite a large heatsink, the 317 gets quite hot no doubt because of the voltage drop across it with a reverse connected, partially charged battery.I have the current set to just under 130 mA (battery is 12 v, 7AH).I'm going to set up a 2N3055 pass transistor (probably overkill but I have a bunch of them lying around) to relieve the load a little on the 317.

author: oldway
author_rank: Super Contributor
timestamp: March 04, 2015, 01:31:17 pm
content: QuoteIt seems a little overkill...With no break's, we replaced such low capacity batteries (with fast-on connectors) every two years.QuoteAs far the battery is not completely discharged and voltage polarities of the battery are not inverted, reverse charging is the same as discharging the battery.Why use a LM317 to do this ?You can use a simple power resistor or an incandescent bulb.But I do'nt agree with this: completely discharge the battery will not desulfate the battery, nor charging with reverse polarities, it will only make the situation worse.

author: eneuro
author_rank: Super Contributor
timestamp: March 05, 2015, 02:16:29 pm
content: Quote from: oldway on March 04, 2015, 01:31:17 pmI do want keep battery at safe volatge levels during desulfation and charging, so added in my desulfator prototype monitoring of input voltage pulse and battery voltage to triger switch in this based voltage multiplier desulfator when those voltages are at proper levels, so it will stop desulfation/charge if battery voltage will be above its floating voltage (will resume later when goes down or slightly discharge battery) or wait for input pulse voltage to be above lets say 10.5V, so another battery can be used as power source if someone wants to experiment moreSo, far less than 1KB of AVR ATTiny85 code and it looks like this small monster will make this desulfator/charger smart and allow remote monitoring of battery for more scientific approach to investigate desulfationIt could be nice to measure battery internal resistance from time to time, so maybe adding power resistor and mosfet switch will be good idea and additionally it will let us experiment with discharging battery from time to time, so if we can charge/discharge we can implement many interesting desulfation schemes

author: eneuro
author_rank: Super Contributor
timestamp: March 13, 2015, 07:00:56 pm
content: Reused optoisolated gate driver prototype in desulfator project, so was able connect everything togetherUnfortunatelly in a hurry connected car battery... in reverse on right side of desulfator-hopefully caps didn't explodedJust trying figure out why in circuit like above (100uH 2A , not 1mH) those 50V 2x 470uF in parallel caps only got very hot in a few seconds when -12V old car starter battery applied in reverse, but they still looks like brand new, however didn't desoldered them yet to test aloneNo caps "magic smoke"why?Update: There is some hope, but 15% of 50V is only 7.5V, so probably no chance those two caps survived -12V reverse polaritydigikey: Reverse VoltageQuoteBTW: I had of course protective glasses

author: MrAl
author_rank: Super Contributor
timestamp: March 14, 2015, 06:24:22 am
content: Hello there,Some things that in theory seem possible are just too complicated to actual get to work in real life. The Space Shuttle was scrapped even though it worked to some degree, time travel is theoretically possible but no human can do it today.In the case of the 'desulfator', the nature of the failure has to be understood first. If the battery is dry inside it will never work again no matter how long we leave in on the 'desulfator' because it needs liquid to work as well as new plate surfaces. So the liquid level is one measurement that has to be done first, but there are probably other measurements that have to be done in order to vary the process well enough to get anything useful to happen.Is it even possible to remove anything on the plates electrically? We all think it is possible, but what if the pulse width has to vary with say the thickness of the material that is covering the plates? What if it also has to be extremely slow, so slow that it takes a year to do correctly?I bring this up because the process is a little like 'mixing', where we have a solution that separates over time and we'd like to mix it back together again (such as paint) using vibration. Can we do it with just two electrodes and some current? I dont think so, but even if we physically vibrate the container we have to know what frequency to vibrate it at. If it is too fast it will actually cause more settling or else just not do anything at all, even though we leave it there for a week, vibrating constantly.So if this is to be done at all, we have to know each and every physical parameter that affects the 'desulfating' process so we know how to vary the drive mechanism properly.I built a 'desulfating' circuit a while back, used it on a 6v lead acid cell. Left it on for days and it maybe increased the charge a little bit. It was built from a microcontroller and a very high current MOSFET for the switching, and had high value capacitance to ensure a high current pulse was sent through the battery.The battery was only used about 6 months prior to that and showed signs of what we call sulfation.My confidence in this working with out much more research is so low that i have to put the word 'desulfator' into quotes every time i want to say it :-)If someone can suggest a safe and not too difficult way to disassemble a lead acid battery (small sealed type) and place it into a clear plastic case, i'll try doing it again and observe the surface area of the plates and see what happens.

author: oldway
author_rank: Super Contributor
timestamp: March 14, 2015, 10:46:51 am
content: It seems sure that the electric desulfation works, at least partially.This is proved by tests demonstrating the recovery of a portion of the capacity after electric désulfation.But it lacks clear scientific explanations and demonstrations to prove it.The first problem is to verify if the loss of capacity is due to sulfation or to other cause.There are indeed other possible causes for loss of capacity as corrosion or active material that frees up from the plates and that fell to the bottom of the battery or of the envelope.If it is caused by sulfation, you must also check in what circumstances sulfation happened.- Progressive sulfation during normal use.- Total sulfation after prolonged total discharge.Both cases are not the same.In the first case, only a part of the plates is covered by sulfate and this layer is thick and irregular.In the second case, all plates are covered by sulfate of a substantially uniform thickness.How does the electric désulfation works?Certainly not by the fanciful theory of resonance of lead sulphate crystals that would break under vibration ...It is a scientific nonsense that only those who knows nothing about chemistry and science can believe.This theory is based on the piezoelectric characteristics of crystals.The objections are:- The deformation of a crystal depends on the electric field to which it is subjected.Now, the pulses generated by electrical désulfators cause only a small change in voltage at the terminals of the battery, and therefore the electric field is low and insufficient to cause a significant deformation of the crystal.- The resonance frequency depends on the dimensions of the crystal. They are different from one crystal to another.For a resonance and amplification of vibrations, there should be applied a constant electric field of a frequency equal to the resonance frequency of the crystal.Pulses only generate damped oscillations.- It is very difficult to break a crystal (or perhaps impossible) by piezoelectric effect in the air.The electrolyte dampens the oscillations, it is obviously impossible to break lead sulphate crystals under these conditions.- it would be easy to reproduce this and to shoot it if it really would be possible.This theory is pure bullshit ...One finds no valid scientific explanation on the Internet.

author: eneuro
author_rank: Super Contributor
timestamp: March 14, 2015, 11:06:58 am
content: Quote from: oldway on March 14, 2015, 10:46:51 amWe'll seeAnyway, it looks like those two caps 50V 470uF caps reversed for a few seconds with -12V doesn't seems to be damagedJust made charge & discharge test and got the same time around 64s of discharge from 24.8Vmax to 1.0V via 21k resistor like with another two caps never reverse powered.Expected they are shorted, but it looks like they blocks DC voltage and 12VDC 5W light bulb isn't shining in my eyes, discharges in the same time like brand new ones, so those caps doesn't looks like damaged onesNow applied 25V voltage via this light bulb to limit current in the case of short circuit and will leave them for many hours to see if it works, but while it is desulfator prototype will let it go with those caps and additional fuse of course on battery sideProbably it will be good idea to add a few lines of code to allow changing desulfator frequency on the fly using potentiometer during first tests-starting from 1kHz to 10KhzIf desulfator will not work... it will be of course ONLY due to those reverse powered caps on battery sideBTW: Yep, those caps looks like have close to its nominal capacity when entered experimental data into derived formulas for capacity we get experimental:~950uF, while 2 x 470uF is 940uF theoretical +/- tolerance, etc, close to those caps specsCode:Vo= 24.8VVc= 1.0Vt= 64sR= 21kC= 0.000949 F ~ 950uF

author: Fraser
author_rank: Super Contributor
timestamp: March 14, 2015, 11:33:22 am
content: It would be a good idea to create some 'test cells' that could be visually inspected during desulphation experiments. What I would suggest is the removal of the six individual cells from a sulphated battery. The individual cells are then placed in their own test chambers that may be observed with a strong magnifier or microscope (better choice). The behaviour of the battery plates could then be monitored directly and adjustments made to the treatment regime to determine which works best.Personally I would start with the convenience of a 2V lead acid gel battery commonly used in alarm bells and Radio Control Glow Plug engines. The cell can be easily extracted from its shell and reinserted if required. I would also prefer working with a sulphated wet lead acid car battery during testing as it removes the issue of dried out cell mats.Experimenting with the plates sealed inside the battery is working blind and so difficult to monitor.It goes without saying that working with Sulphuric acid requires suitable safety precautions and correct handling.Cutting around a Gel battery top weld releases the cells from the case.Am I interested in doing this? Nope, as already stated, I no longer have an interest in recovering knackered lead acid batteries. Life is too short alreadyAurora

author: eneuro
author_rank: Super Contributor
timestamp: March 14, 2015, 03:55:39 pm
content: Quote from: Aurora on March 14, 2015, 11:33:22 amInternal resistance should improve as well as capacity in desulfated battery, so it can be tested.Anyway looking for small visual camera with small optics to put it in glass housing inside battery cell to spy those plates surface changes in real timeFirst run through light bulb at 8kHz ~5us ON ~4% duty cycle and... looks like current flows and energy disipated on battery side however not sure into which directionTried also without light bulb and nice a few kHz sound, so something is going on thereImplemented in MPU that PWM pulse will be send only when voltage on caps on transformer power side will be higher than battery voltage, so there is no chance that battery charges this power side caps when switch is turned on.No time today for futher investigation and current/voltage scope waveforms, etc-need to simulate this thing at higher frequency than 1kHz to see what to expect, but nothingand energy disipation on battery side cleary visible at least in light bulb, which was added to simulate higher battery internal resistance and to limit output current in first runs of this desulfator

author: oldway
author_rank: Super Contributor
timestamp: March 14, 2015, 07:01:52 pm
content: QuoteThe fact that it seems sure that the electric desulfation works does not mean that any desulfator will work.We should first understand how the electric desulfation works to project a correct device.Surely, this can't not be based on the stupid principle of resonance of lead sulfate crystals.As I said before, professionals desulfators produce high current pulses (of the order of 50A peak for a 100Ah battery) of approximately 200 ms every 3 or 4s.This is my personal theory about that.For sulfated batteries after a long deep discharge, internal resistance becomes very high and the battery will not accept the charge.- The acid is transformed into sulfate during the discharge and the electrolyte becomes almost pure water.The electrolyte is then a poor conductor of electricity, which greatly increases the internal resistance of the battery.- The sulphate layer is insulative and prevents current flow.According to my tests, at least part of the battery capacity can be recovered by initially charging the battery with a much higher voltage (30 or 40V for 12V battery) but by limiting the current to about 1A by a serial power resistance. (22R 25W)Once the voltage across the battery drops to 12V, it can be recharged with a normal charger.I do not know if we can recover the full capacity of the battery that way.For batteries sulfated in normal use, manufacturers recommend charging flooded batteries with a higher voltage for an hour each week as a preventive maintenance.To eliminate this sulfation, the problem is to dissolve the crystals of sulfate.This is difficult, the purpose of desulfation is to get there by boosting the battery voltage for short periods.You should know that:- Sulfate is very little soluble in water, but a little more soluble in sulfuric acid.- As the electrolyte is saturated with sulfate, it is no longer possible any dissolution of the sulphate.- It is a slow reaction increasing with temperature rise.

author: Fraser
author_rank: Super Contributor
timestamp: March 14, 2015, 07:37:16 pm
content: IIRC manufacturers suggest that deliberately charging a wet Pb battery at an elevated level will help to reduce any mild sulphation on the plates due to the vigorous hydrogen gassing that occurs (and associated & agitation of the electrolyte). Such 'treatment' is advisable only where any lost H2O may be replaced and where careful monitoring of the battery is possible. Deliberate excessive charging that causes large amounts of out gassing is not something that I would recommend unless you know exactly what you are doing. As a child of 10 I did something stupid with a 12V motorcycle battery ( I was collecting hydrogen gas in a bell jar !). There was a hydrogen gas explosion in the battery and it blew the case apart, covering me in dilute sulphuric acid and removing my eybrowsPlease be carefulAurora

author: tautech
author_rank: Super Contributor
timestamp: March 14, 2015, 07:58:49 pm
content: Quote from: Aurora on March 14, 2015, 07:37:16 pmWarning notedA gassing charge proceedure has been around nearly as long as Pb batteries have and is a well known maintenence step.Yes it must only be used if one can replace the lost H2O.

author: SeanB
author_rank: Super Contributor
timestamp: March 14, 2015, 08:04:53 pm
content: I am reminded of a story about a large company, which used a large number of electric forklifts. It involved a smoker who lit a cigarette, next to the large room in which there were around 40 battery boxes being charged, which resulted in the destruction of all of them along with the room. He, along with the operators of the charge station, survived mostly intact. He still smoked afterwards, too thick to take heed of the warning.

author: tautech
author_rank: Super Contributor
timestamp: March 14, 2015, 08:15:34 pm
content: Quote from: SeanB on March 14, 2015, 08:04:53 pmThe sparks from maintenence grinding near a battery charging can have a similar result.Many a small commercial workshop has learnt this the hard way and battery areas should be well away from any engineering.

author: oldway
author_rank: Super Contributor
timestamp: March 14, 2015, 09:12:44 pm
content: A big mistake that some people make: do not remove the caps during charging.Another one: Do replenish with distilled water only after charging the battery, not before.NB: If level is very low, you may add a little water.

author: eneuro
author_rank: Super Contributor
timestamp: March 15, 2015, 10:03:49 am
content: Quote from: oldway on March 14, 2015, 07:01:52 pmNot such a big deal output high current in voltage doubler based desulfator I've changed for even higher currents and added axternal power supply.After playing more in circuit simulator quickly found a way to limit heating of battery side inductor and diode at higher switching frequencies and changed software to enable different operating modes including from self powered battery without external power supply-in this case we get classic voltage doubler desulfator described in linked posts above, but with battery undervoltage and overvoltage protectionBy adding additional current limit between higher voltage power side and battery, charging and desulfating possible at the same time and it doesn't affect output current spikes which are limited by wires inductance and parallel capacitors resistance.Very nice a few kHz frequency noise close to desulfator battery side, similar to... piezoelectric buzzer, so it might destroy those bloody crystals if not by resonance, than like in spot welding by raw powerAnyway this crappy multimeter gone crazy at 200V range when tried measure output voltage on desulfator battery terminals and showed... close to 90VIt works now without any significant heat dissipation, but even with high short current pulse AC mosfets switch at a few percent duty cycle of course will not disipate too much heat as expectedI have battery overvoltage protection implemented before high voltage pulse is send, so now it time add a few fans and let it go for more time to see if nothing gets hot and add I2C interface to monitor this thing from remote control room on laptop screens

author: Mosaic
author_rank: Regular Contributor
timestamp: July 25, 2017, 11:22:53 pm
content: Sorry to disturb the old thread but here's something modern and tested that works. DIY & open sourced. It is my design and it is tested over hundreds of batteries. I have data logs of many of them.https://hackaday.io/project/25741-desulfator-engine-re-climate-change-mitigation

author: floobydust
author_rank: Super Contributor
timestamp: July 26, 2017, 12:03:38 am
content: Finally someone putting enough energy in to breakdown the sulfate crystals. I don't understand the chemistry involved but every desulfator I've built was a giant waste of time, peanut size pulses and then I realized it was snake oil.It looks like you are using 36VDC 6,600uF capacitive-discharge; graph shows 640Apk into a Group 55 car battery, is that correct?

author: floobydust
author_rank: Super Contributor
timestamp: July 26, 2017, 04:57:24 pm
content: Mosaic open-sourced his build and started a new thread here:https://www.eevblog.com/forum/oshw/desulfate-regenerate-lead-acid-batts-a-new-diy-guide-overnight/

author: Dehv
author_rank: Contributor
timestamp: November 27, 2021, 09:40:24 pm
content: There's a research paper that's paywalled but indicates in the abstract a slightly interesting variation on the theme, bringing down to 0 v then REPLACING TGE ELECTROLYTE and reverse charging at CC for 24 hrs then back to normal polarity charging for 48.Claims are to recover 80% of capacity.

author: Dehv
author_rank: Contributor
timestamp: November 30, 2021, 04:35:29 am
content: Found it. Attached: pdf"RECOVERY OF DISCARDED SULFATED LEAD-ACID BATTERIES BY INVERSE CHARGE"2009 original paper by Karami.And a more comprehensive but I find not as practical expansion on the above work at the followinghttps://www.google.com/url?sa=t&source=web&rct=j&url=https://academiccommons.columbia.edu/download/fedora_content/download/ac:206709/content/Spanos_columbia_0054D_13754.pdf&ved=2ahUKEwjanIf1nb_0AhXrFjQIHWG2AmsQFnoECBMQAQ&usg=AOvVaw2e5UZOnEZztAd4oLA4p-qi

author: Dehv
author_rank: Contributor
timestamp: December 04, 2021, 12:25:07 am
content: In the karami pdf abstract it seems to state the procedure is to replace the acid with new after discharge, however nowhere in the rest of the document is that mentioned.The other studies reference it as "according the procedure by Karami"Without restating if acid is changed at any point.Well ain't Dat a dill pickle.