Desulphator recomendations - Page 1
Forum section: electronics / beginners

author: pcm81
author_rank: Regular Contributor
timestamp: September 04, 2022, 08:13:10 pm
content: Looking for recommendations for a dedicated 12V lead acid desulfator. Just got the BatteryMINDer 2012 and up until now been doing desulfation with just current limited CV power supply. Mostly looking to restore lead acids from APC ups units and car Starter batteries.Would a dedicated desulfator do a better job than battery minder? Budget couple hundred usd; not interested in $20 chinese crap.Thanks

author: pcm81
author_rank: Regular Contributor
timestamp: September 04, 2022, 08:26:22 pm
content: Just wanted to add that i do not need a dummy proof set it and forget it solution. Looking for a good tool or set of tools and if they require me to use my brain, that is OK.

author: macboy
author_rank: Super Contributor
timestamp: September 05, 2022, 02:53:34 am
content: You want to desulphate old UPS batteries to restore them? My recommendation in that case is: don't waste your time. I've tried many times, never had success with that, just lots of wasted time. Flooded batteries (car batteries) might be a different matter. I have little experience there so I'll leave advice-giving to someone who has more.

author: pcm81
author_rank: Regular Contributor
timestamp: September 05, 2022, 04:58:24 am
content: Quote from: macboy on September 05, 2022, 02:53:34 amYour experience matches my own, although i was hoping that my "marginal" successes with UPS batteries were driven my my use of power supply. I have successfully "extended" some ups batteries lifespan by about a year, but not much beyond that. Trying a 2nd desulphation on a set now; already extended by 8 months from initial failure.

author: Terry Bites
author_rank: Super Contributor
timestamp: September 05, 2022, 10:04:38 am
content: I think this will only add unreiliablity to ther UPS- the oposite of the idea.

author: CaptDon
author_rank: Super Contributor
timestamp: September 05, 2022, 01:11:38 pm
content: I agree 100% with Terry. Those UPS batteries are not sulphated, they are cooked dry from constant charging. If you want to extend their life make them work. Once a week pull the UPS plug for a few minutes and let the UPS run on battery carrying the load. Who would put unreliable capacity compromised recycled batteries into a critical power system? Once those batteries are supposedly desulphated you should consider storing them in the nearest dumpster since that is their real world value. Wet car batteries do a little better but I wouldn't stake my life on it. The problem with desulphated wet batteries is their internal leakage and compromised crumbling plates. Leave them sit for a week without use and they are dead again and after messing with them endlessly trying to keep them up to full charge one day you wake up to a shorted cell that won't pass much current.

author: Stray Electron
author_rank: Super Contributor
timestamp: September 05, 2022, 01:22:24 pm
content: Quote from: macboy on September 05, 2022, 02:53:34 amI absolutely agree in the Captain here. I've seen HUNDREDS of posts about people trying to desulphate batteries and none of their attempts have been successful. Just to start with, many battery failures have nothing to do with sulphate layers, most of the time the battery plates crumble and fall into the bottom of the cell and short out individual cells. You'd have better luck trying to catch unicorns than rejuvenating old batteries.

author: pcm81
author_rank: Regular Contributor
timestamp: September 05, 2022, 03:05:37 pm
content: While technically speaking i agree with most recommendations in this thread, let me add some context:The batteries in question are inside 3x Smart-APC-1500 units that power my computer. We're not talking a google server farm UPS here.The failure is when APC UPS fails a self test.I have been successfully running for 1-2 years with batteries that were "repaired" by me after the initial APC fault report.My standard repair is to open the battery, top off with water if needed. If very dry might even place in vacuum chamber to let water settle into all the cavities. Once water top off is complete and i verify there are no short cells, i start a maintenance charge that is voltage limited to 14.4V and current limited to 1-2A depending on size of battery. At this stage the valves are still open and battery is allowed to out-gas. This part takes a while. Slow and steady wins the race. Sometimes it fails and i get a short; at other times i can get another 12 months out of a battery. Looking for a good quality pulse/frequency desulphator that i can use in place of power supply for this phase.Had a battery mender on my later batter repair for about 18 hours and it has definitely helped beyond what 14.4V charge did already.A CAUTION: if anyone is reading this thread and attempts to use my method; keep in mind that you may need to start at less than 14.4V. Goal is to keep voltage across each cell below 2.5V to prevent electrolysis. The 3 ways to determine that you have electrolysis happening are:1. a specific cell is bubbling aggressively2. voltage drop across 1 cell is 2.5V or more3. after a small amount of voltage rise across the battery you get a spike in the current (this spike is because you pushed voltage across 1 cell above 2.5V an electrolysis is eating your current).

author: pcm81
author_rank: Regular Contributor
timestamp: September 11, 2022, 06:26:52 pm
content: Observed something interesting in last 2 days.I had the lead acid batteries on batteryminder 2012 desulfator for couple of days. Received SkyRC BD250 discharger and tested the batteries again. Capacity dropped to ~2AH from 6AH that chinese discharger reported few days earlier. Then did full recharge and discharge by chinese discharger, which now also reports about 2AH capacity. So basically capacity dropped from 6AH to 2AH as the result of desulfation. Electrolyte is full and voltage stays around 12.6V for most of the discharge cycle. Strange... Tried discharge rates from 0.5A to 4A and all produce between 2AH and 3AH.The same behavior is observed on 2 12v 18AH (new capacity at c/20) batteries. Strange...

author: Gyro
author_rank: Super Contributor
timestamp: September 11, 2022, 07:05:04 pm
content: That sounds like the plates corroding / losing mechanical integrity, so there is less active plate area in circuit.

author: --Oz--
author_rank: Regular Contributor
timestamp: September 11, 2022, 07:27:44 pm
content: I played with desulfators for a while, my conclusion = snake oil would be a better investment, haha.I recovered several ups batteries, most where 12v 7ah size, one charge, one discharge gave less than 1ah, baked dry as a bone. Tried 3 different solutions in the three batteries, it upped the capacity to almost 2ah.Then I played with my desulfator, I built and tweaked it a bit from other schematics online, total cost was $5 (fet/ind/diode all scavenged from a dead psu). But mine was adj freq and duty cycle and it would desulfate when charging or discharging. I tried all kinds of freq/duty setting (this has a large effect on charge rate). Lucky I was doing this at work, four months of testing revealed a big fat ZERO improvement, haha.I needed a new 12v lead battery charger after a friend did not return my old school non-smart charger, so I got one with desulfate mode, again, zero improvement. I looked at what freq/duty this unit did and I already tried these settings. But I tried using it and had the same pitiful results as my unit gave.Another victim of desulfating hype, invest in snake oil, will save time and money, lol.

author: Gyro
author_rank: Super Contributor
timestamp: September 11, 2022, 07:34:27 pm
content: It's probably worth mentioning that scrap metal dealers (in the UK at least) will pay a surprising amount of money for dead Lead Acid batteries. They are very recyclable.It's something to get you started on replacement cost anyway.

author: pcm81
author_rank: Regular Contributor
timestamp: September 11, 2022, 07:50:35 pm
content: Quote from: Gyro on September 11, 2022, 07:34:27 pmYeah, I've been playing with desulfating for few years now. Every time i get dead battery i try to do it. First just used dc power, now playing with battery minder.I did couple of times extended 12v battery life by about a year, but that is hit and miss and overall i consider these efforts as "playing around" definitely not a reliable recovery technique for bad battery.

author: --Oz--
author_rank: Regular Contributor
timestamp: September 11, 2022, 08:04:50 pm
content: Maybe a better way is to empty the battery if its not already cooked dry, then clean the plates with some solution, rinse and replenish with correct electrolyte?

author: SmallCog
author_rank: Frequent Contributor
timestamp: September 12, 2022, 03:03:57 am
content: I recovered 4x 160A/Hr Full River AGM batteries from a solar installation a few weeks back. These were all installed together from the same batch of batteries, charged by the same PV array and regulator.There was a reasonable draw on these batteries overnight, they were cycling not just sitting there being floated each day doing nothing.Batteries were around 6 years of age and I tested them with a Matson battery meter. One battery had a state of health of 100%, another was in the low 50's and the other 2 were in the 70's or 80's(Meter I used:https://www.tridon.com.au/products/Matson/4079/338805/battery-testing/529006/digital/434668/BTJ41)Before sending them for recycling I decided to do an experiment and see how they did after the magic "rejuvenation" that most chargers claim to do these days.I charged the batteries separately, but concurrently with 4x 7A chargers(4 of these:https://www.projecta.com.au/products/IC7/intellicharge-7a-bat-chgr)After the charge cycle had finished I let the batteries sit for 24hrsAll of the batteries were then tested with the same Matson meter and tested as being in significantly poorer health!I'm not fussed they were going in the scrap bin anyway but it was an interesting little experiment.On the topic of UPS's I've replaced the packs in a few Eaton UPS's lately and have observed that when testing the individual 12V batteries that it's typically only one that's dead, the other 7 (I think it's 8 in these UPS's I can't be bothered checking) typically test as being in reasonable condition.I've got a few living a second life doing useful things. I'd not trust them with anything critical, but a faulty UPS pack could potentially give you some useful batteries for something else if you have a way to sort the wheat from the chaff.

author: pcm81
author_rank: Regular Contributor
timestamp: September 12, 2022, 04:21:23 am
content: Quote from: --Oz-- on September 11, 2022, 08:04:50 pmThere is plenty of electrolyte in them. I topped them off before starting this "experiment". I usually do these reconditionings with valves off but ports loosely covered by some kind of plastic, just to prevent spatter.

author: james_s
author_rank: Super Contributor
timestamp: September 12, 2022, 06:17:50 am
content: Quote from: Gyro on September 11, 2022, 07:34:27 pmIndeed. Several years ago I gook nearly 300 lbs of dead lead acid batteries, mostly UPS batteries and a few car batteries that had accumulated at a friend's business to a scrap metal dealer and got around $80 in beer money for them. I'm pretty sure they're worth significantly more now so I would certainly not throw them away, just put them in a pile and cash in when you have enough. At the very least drop them off at an autoparts store for recycling.

author: james_s
author_rank: Super Contributor
timestamp: September 12, 2022, 06:20:29 am
content: Quote from: --Oz-- on September 11, 2022, 08:04:50 pmI've taken apart a few and in every case half of the plates had been reduced to a crumbly orangish muck. They weren't something you could clean, they fell apart into crumbs.

author: --Oz--
author_rank: Regular Contributor
timestamp: September 12, 2022, 06:25:13 am
content: Quote from: pcm81 on September 12, 2022, 04:21:23 amWhat I mean is the plates on most dead batteries are wasted, probably the plates are coated and baked on sulfur (I am guessing).I was thinking, empty out the continents, put in some magic solution that would clean the plates (maybe with a electric current), dump this solution out, rinse and fill with electrolyte and recharge (hoping to be similar to new), or just buy a new one, haha.I have never liked lead acid batteries and still dont.I have ridden street motorcycles (Yamaha and Honda 600cc and 1000cc) for 3 decades, these 12v 10Ah batteries are horrible, Most use a top brand name Yuwasa. I finally saw them at a motorcycle convention and asked what's up with their batteries, what do you mean, I said I am replacing them about every year,,,with no answer, I asked how many life cycles should I get out of a new battery, they said 1500, I laughed, I am thinking I get less than 356 cycles, but wait, I only start the bike for 1~2 seconds, so I asked, I can fully charge, then fully discharge 1500 times? Ohhhhh NO, 2 sec discharge and recharge is considered 1 cycle, I said this is horrible product.

author: james_s
author_rank: Super Contributor
timestamp: September 12, 2022, 04:55:23 pm
content: Quote from: --Oz-- on September 12, 2022, 06:25:13 amThat's just the nature of lead acid batteries, they are well suited to shallow discharges and float charging, no lead acid battery can survive 1500 dischages to zero. Yuasa is a quality product, the problem is likely to be the lousy charging circuitry in the average motorcycle.

author: --Oz--
author_rank: Regular Contributor
timestamp: September 12, 2022, 07:54:01 pm
content: Quote from: james_s on September 12, 2022, 04:55:23 pmI dont believe it was the onboard charger circuit, but thats for another discussion.Lead acid has been around for a century, you would think they would be better by now, but then again, sales want to keep selling you more, so why make it last too long, I think thats the main reason.Take 1500 cycles out of a motorcycle battery, 12v 10Ah, with not even 100A two sec discharge (or a peak of 10C discharge).Now take my LiPo drone battery, my quad is high preformance and can accelerate at 9 G's, corner at 15 G's, uses 4s-1300mAh tiny battery and if I full throttle lasts 1 minute flight time. But with the amount of tricks I do, I fly 90 seconds per flight, this is many 120A peaks on a tiny 1.3Ah pack (1800W), 100% to 40% discharge in 90 sec (45x the discharge time of the lead), and after 1200 flights (~5 years), I now use them in my planes where 1 motor is fine and the pack is now over 2200 flights and still going. Summery, tiny battery (roughly 50x smaller than a motorcycle batt), huge discharge currents to its relative size (90C, 9x what a lead acid does and easily), cost $13 in 2016, the good LiPo's today are even better than the battery I just talked about. I just expect more from a century only tech battery, and thats why I still hate them, haha.

author: james_s
author_rank: Super Contributor
timestamp: September 12, 2022, 08:00:52 pm
content: Yes I'm well aware of LiPo batteries, I have piles of them for my airplanes. They are not the same thing as lead acid batteries, not even close. I'm sure at some point in the future lithium ion or better yet, lithium iron batteries will displace lead acid in applications like motorcycle starting batteries but so far they have not. LiPo requires much more complex charging and management circuitry, it can fail spectacularly if overcharged and it will degrade rapidly stored fully charged or at elevated temperature so it is a poor choice for engine starting. LiFePO4 is much more robust but still more expensive than lead acid and requiring more complex charging circuits. With a good charging circuit a lead acid battery can last years in that application, but if it is overcharged or allowed to sit until it discharges too low it will rapidly degrade.

author: SpecialK
author_rank: Regular Contributor
timestamp: September 13, 2022, 12:08:58 am
content: Are you guys saying you can service these small 9AH SLA or VRLA batteries in UPSs? I have never noticed any caps on them to add distilled water. I thought the electrolyte was a gel. I.e a gel cell.

author: james_s
author_rank: Super Contributor
timestamp: September 13, 2022, 12:17:14 am
content: Yes there are caps, yes you can add water to re-moisten the gel, and yes it will often result in a small improvement, but it is ultimately a waste of time because the battery is still shot. You might take it from completely dead to having 5-10% of rated capacity, the plates themselves are deteriorated and you can never really fix them.

author: --Oz--
author_rank: Regular Contributor
timestamp: September 13, 2022, 12:33:42 am
content: Yes, caps under the cover.Adding distilled water is the best thing you can do to these "sealed" batteries imo. And should check them every year (or 6 months) before they are charged cooked to early death.

author: SpecialK
author_rank: Regular Contributor
timestamp: September 13, 2022, 12:35:55 am
content: That reminds me of the owners manual of my 2010 Mazda3 that states:"Inspect the electrolyte level at least once aweek. If it's low, remove the caps and addenough distilled water to bring the levelbetween the upper and lower level"Oh really? Atleastonce a week? Like there are people doing this 2x weekly? Weird advice considering the battery installed was maintenance free. Not checked once ever and replaced after 6 years before it became undependable.

author: SpecialK
author_rank: Regular Contributor
timestamp: September 13, 2022, 12:42:37 am
content: Quote from: james_s on September 13, 2022, 12:17:14 amI think I might weigh and mark the weights on the side for giggles. See how much evaporation takes place yearly. But only for open battery trays. Battery boxes are a PITA. I can test internal resistance of the whole assembled pack way easier with my electronic load.

author: --Oz--
author_rank: Regular Contributor
timestamp: September 13, 2022, 01:11:05 am
content: Quote from: james_s on September 12, 2022, 08:00:52 pmYes correct on the lipo info, I was just saying that the gains in the last 20 years of lipos it really beats the improvements that the lead batteries to death (size, weight, capacity, IR), but not a proper drop in replacement.I have seen racing batteries with LiFe cells and internal bms as drop in replacements for motorcycles lead batteries. You are correct about the heat, but just mount it in the trunk and instead of charging to 4.2v, that kills them when sitting, only charge to 3.9 or 4.0v per cell. It does boil down to cost. Relativity soon the lead batteries will fade away for the most part because electric cars are coming.

author: --Oz--
author_rank: Regular Contributor
timestamp: September 13, 2022, 02:59:45 am
content: Here is a life motorcycle battery a friend gave me after it failed, he does track days. The bms failed due to water getting on the bms (it's taped to the top of the battery after I removed it and add a ballance connector). It has flat pouch cells in the lower 60% of this case, which is half the size of a lead battery and so much lighter.The label says 12v 19Ah, which is way high for a lead battery. It tested it to 6.8Ah and 2.1mOhms per cell on my Wayne gills IR meter, pretty impressive.

author: james_s
author_rank: Super Contributor
timestamp: September 13, 2022, 03:11:00 am
content: Something worth mentioning if you're playing around with adding water to these little SLA batteries, or ANY lead acid battery really, *always* wear safety goggles and be very careful peering down into the holes. They can spit acid, especially while charging and you don't want sulfuric acid in your eye.

author: aargee
author_rank: Frequent Contributor
timestamp: September 14, 2022, 02:40:03 am
content: IMHO... desulphation, if it indeed will work with your battery, should be undertaken before the battery fails. i.e. as part of ongoing maintenance.Once a battery has failed or is showing severe signs of reduced capacity, the rot (literally) has set in to the plates.My observations only with limited interaction with flooded, AGM and Gel type lead acid batteries. I do it regularly to a vehicle AGM battery in a stop-start vehicle, the battery is now seven years old and the stop-start function is always disabled for battery longevity.