Advanced Desulfator for Lead-Acid Battery Resurrection - Page 1
Forum section: electronics / projects

author: gevv
author_rank: Contributor
timestamp: January 23, 2024, 01:17:48 pm
content: Hi, Basically, it works as an increasing converter ("boost"), composed of elements L2, T3, D2. Because we want to send pulses to the accumulator, no filter is included at the output of the step-up converter. Since we want to power the device from the same source - the battery that works in the island power (or other) system and that we want to desulfate, it is necessary to create a fixed potential from which the boost converter will be powered. This is ensured by the low-pass filter formed by the LC filter consisting of the coil L1 and capacitors C1 to C4.30A PeakLow voltage protectionHigh voltage protectionOver temperature protection (above 50 degrees)The function of the power part is controlled by the well-known NE555 timer connected as an astable flip-flop. The length of the pulse to the gate of the transistor is determined by the combination of R2 and C6 and determines the switching time of the transistor M1 and thus the strength of the pulse. With the components used, the pulse length is about 15 us, which will "charge" coil L2 to a current of about 30A. After the end of the pulse, this current is discharged through diode D2 into the accumulator. The discharge time is given by the combination of R4 and C6 and is about 150 us, which corresponds to a repetition rate of about 6 kHz.Source

author: CaptDon
author_rank: Super Contributor
timestamp: January 23, 2024, 02:20:37 pm
content: A sure way to blow up a smart charger. The most common lead acid batteries to sulphate are garden tractor and motorcycle batteries. Gel Cells are a lost cause since generally they don't die of sulphation but rather dried out electrolyte. What is the number one lesson everyone has learned with every desulphation gimmick on the market?If the battery is dying from sulphation it is already 80% 'kaput'!!!! Would you desulphate your motorcycle battery and then head out on a cross country trek?? Doubtful!!! You will never get back the original cold cranking amps and that is what matters and whatever lead to the battery being sulphate contaminated in the first place is simply going to happen again but 3X faster. Those crystalline structures are harder to break up than kidney stones. Maybe use ultrasonic impacts on your battery like the Urologists use on kidney stones would be more rewarding? I love all of the witch doctor remedies for batteries!!! Dropping aspirins into the cells, or the ever popular VX-7 battery remedy sold by J.C. Whitney back in the day. Can you imagine being stranded in rough seas because your Captain's engineering wing desulphated the batteries instead of replacing them?

author: Stray Electron
author_rank: Super Contributor
timestamp: January 23, 2024, 07:22:46 pm
content: We were overdue for the semi-annual 'resurrect the dead batteries gimmick' thread. Sorry OP, nice design work but NONE of these devices have EVER been shown to be effective. You can go back to the past discussions on this forum (and many others) to find the many reasons why.

author: floobydust
author_rank: Super Contributor
timestamp: January 23, 2024, 08:31:02 pm
content: For over 100 years, mankind has tried to overcome sulfation in lead-acid batteries. Every chemical imaginable has been added to the electrolyte, to the plate material - with little benefit.You can check today's science, where they look at the sulfate crystals with Transmission Electron Microscopes (TEM). Lead sulfate PbSO4crystals build up in the pores of the plates, are insulators, and are very stubborn or impossible to dissolve outside of regular charging.There are a few pseudo-science circuits that claim fame and glory but nothing truly works:Lead acid battery Regenerator (12KW pulse power) DIY.was claimed to be 12kW pulses, and of course hogwash. At least it didn't blow up in his face.Desulphator recommendationsRecover Dead Battery using 555 Timer IC, really?!etc.

author: kripton2035
author_rank: Super Contributor
timestamp: January 23, 2024, 08:35:06 pm
content: I would just like to know with what software did you make this colorful schematic ? thanks.

author: KerimF
author_rank: Frequent Contributor
timestamp: January 24, 2024, 03:56:40 am
content: Lately, I designed one, but by using an external supply. And it is controlled by an MCU (ATmega8) in order to monitor:1- The pulse peak voltage on the battery (which is expected to decrease with time for the same peak current)2- The rate of pulses3- The total number of pulses (unit 50,000 pulses)and to adjust:4- The pulse peak current (up to 100A for the time being)5- The rate of pulsesI did it just for experimenting and verifying the Desulfation theories on the web.Now, I wait to have a sulfated acid battery

author: CaptDon
author_rank: Super Contributor
timestamp: January 24, 2024, 01:54:05 pm
content: Go to any battery store and look through their junk pile of traded in batteries. Find one with removable cell caps. Sulphate is a pink or white material adhereing to the plates and can easily be seen. They would probably sell the junk battery to you for around $10 U.S.D. since that is the trade-in core value.

author: floobydust
author_rank: Super Contributor
timestamp: January 25, 2024, 12:24:53 am
content: There is a temptation to crank up the pulse power to dislodge the sulfate crystals, out of frustration to get some results.I hope people realize extremely high pulse currents and voltages can easily cause an arc and ignite hydrogen gas inside the battery.I've done it, I've seen it and you don't want a sulfuric acid mess, it eats flesh no prob.

author: Miyuki
author_rank: Frequent Contributor
timestamp: January 25, 2024, 06:28:29 am
content: If it is for a starter battery then it is futile as the electrodes are so thin and fragile that they will just disintegrateAnd using lead-acid batteries for energy storage makes no sense unless you have them for scrap metal prices. As the new lithium batteries are cheaper per kWh than lead-acid ones.

author: gevv
author_rank: Contributor
timestamp: January 25, 2024, 08:21:07 pm
content: Hi,@CaptDon👍@Stray Electron I revived completely dead batteries. 👍-water renewal (battery water).-the covers will remain open. wait 1 day.-connect the desulfator and charger.Maybe this and similar circuits are suitable for batteries that are in very bad condition.@floobydust 👍@KerimF👍@Miyuki 👍@kripton2035 Splan 8 👍

author: Randy222
author_rank: Frequent Contributor
timestamp: January 25, 2024, 08:52:53 pm
content: I thought the process was a maintenance process to help keep plates "clean", and not a resurrection process.

author: Randy222
author_rank: Frequent Contributor
timestamp: January 25, 2024, 10:05:31 pm
content: Quote from: Miyuki on January 25, 2024, 06:28:29 amI bought a set of 200AH deep cycle AGM batts for a project, the equiv Li batts were like 5x the cost.

author: Miyuki
author_rank: Frequent Contributor
timestamp: January 26, 2024, 06:30:14 pm
content: Quote from: Randy222 on January 25, 2024, 10:05:31 pmI currently bought 18 cells 305Ah - LiFePO4, for €1,364 including tax and shippng from european distributorI could not find any AGM with a similar price that would not be a complete garbage

author: johansen
author_rank: Super Contributor
timestamp: January 27, 2024, 02:23:47 am
content: What I believe actually works to desulfate batteries is to dump the acid out, replace with distilled water, and float charge the battery at 14 volts for a couple months.The reason this works is because the low concentration of acid, 1.05 or less, produces zero "volts" in a healthy battery. as such the lead sulphate crystals "see" 2 volts across them.where as with the nominal 1.2 sg acid, the natural voltage of the battery is 12.6 or so, and a 14 volt float charge is only pushing .2 volts per cell into the battery.in one case, i got an additional 2 years functional use, out of a 10 yr old car battery that had declined in capacity to just 3 amp hours. after 2 months of float charging after dumping the electrolyte out, the acid concentration rose to an unbelievable 1.2, the amp hour capacity was around 20, and i put it back in my truck.I don't have a good understanding of where the acid came because i may still have the 3 liters of 1.25sg acid i dumped out. in any case, there is about 4-5 times as much "active material" in a lead acid battery than there are amp hours.

author: johansen
author_rank: Super Contributor
timestamp: January 27, 2024, 02:26:16 am
content: Quote from: floobydust on January 25, 2024, 12:24:53 amplate damage to the point of complete separation is the only way you can get a spark inside the battery. its a risk you have to be willing to take.such a spark can occur during starting an engine. the remaining functional plates can heat up, melt, break, and spark.. blowing up the battery. it happens. its not something to be afraid of.i don't really have a problem putting my fingers in 1.25 Sg acid. it hurts under your fingernails but if you wash your hands immediately its ok.

author: floobydust
author_rank: Super Contributor
timestamp: January 27, 2024, 03:14:26 am
content: It is something to be afraid of. Your fingers don't mind the acid but your eyes and face do.The plates and interconnects corrode and disintegrate with age and fall apart.I've seen it when people overcharge (boil) an old battery it makes a lot of hydrogen and it stirs up sediment.Lead fragments land on the plates. What could go wrong? A cell sees a short, the spark causes the battery to explode and sulfuric acid gets everywhere. Hydrogen requires extremely low ignition energy, it lights up super easy.

author: gevv
author_rank: Contributor
timestamp: March 18, 2024, 09:31:21 pm
content: Hello, the long test has begun. Results of the first day. (This is just a simple time test.)- Fully charged expired battery (12v 60ah)- A 10 A load was connected, after 40 minutes the battery voltage became 10 V- The battery was recharged and connected to the desulfation circuit (1 day in total)- A 10A load was reconnected. After 95 minutes, the battery voltage becomes 10V.The process will take a month, now everything is fine. Green light appears

author: KerimF
author_rank: Frequent Contributor
timestamp: March 19, 2024, 03:06:36 pm
content: Quote from: gevv on March 18, 2024, 09:31:21 pmOm my side, I got lately an acid battery whose voltage was 8V and refuses to be charged by conventional chargers (its internal resistance/impedance was relatively high).After pulsing it (50A peak) every 2ms, for a few days, this helped it restore about 20% of its capacity. So, I keep reviving it that way.