Epsom salt in lead-acid battery - Page 1
Forum section: electronics / general

author: Rick Law
author_rank: Super Contributor
timestamp: December 16, 2020, 04:18:32 pm
content: Some web articles and youtube videos suggest reviving a lead-acid battery by adding a solution of Epsom salt in distilled water. Some even suggest draining the old acid and refilling with Epsom salt in distilled water solution.Web being what it is, anyone can claim to be an expert. It doesn't seem right to me, but I am not an expert. So, I turn to the expert here...Anyone here ever tried that? What are your results?EDIT - corrected - Epsom salt, not Epson salt...

author: BravoV
author_rank: Super Contributor
timestamp: December 16, 2020, 04:20:48 pm
content: You mean Epsom right ? Not Epson.

author: Rick Law
author_rank: Super Contributor
timestamp: December 16, 2020, 04:34:59 pm
content: Quote from: BravoV on December 16, 2020, 04:20:48 pmYou are right, I corrected the post!

author: jogri
author_rank: Frequent Contributor
timestamp: December 16, 2020, 04:50:52 pm
content: Doesn't strike me as a valid tactic,since when does the addition of a sulfate to a battery that already has a way too high sulfate concentration lower that concentration? If anything, it prevents lead sulfate from dissolving, making the problem worse. Give it a shot if you have nothing to lose (the battery is dead anyway), but don't get your hopes up.

author: james_s
author_rank: Super Contributor
timestamp: December 16, 2020, 06:36:34 pm
content: I saw a youtube video a while back where a guy tried that on a few different old batteries and it didn't help.The few times I've dissected a worn out lead acid battery it was obvious that there was no saving it. The plates weren't sheets of lead, they were more like sheets of corrosion that crumbled to bits.

author: edpalmer42
author_rank: Super Contributor
timestamp: December 16, 2020, 07:49:18 pm
content: There are many ways that a lead-acid battery can fail. Some are chemical, some are mechanical. If the Epsom salts work at all, it will only be able to fix a chemical problem, not a mechanical one.The biggest chemical failure I can think of is sulfation. Lead Sulfate is hard and non-conductive. Once it forms, it insulates active material under it. I think this is the fault that Epsom salts is claimed to fix. Sulfation also tends to cause the plate to grow larger which can cause mechanical damage to the cell.Mechanical problems that I can think of off the top of my head are:1. Plate corrosion. Vibration, gas generation under the surface of the plate - mostly while charging, and temperature cycling can cause material to be shed by the plate. The shed particles fall down to the bottom of the cell and create a sludge. If the sludge builds up high enough, it'll short out the cell. The shedding process will also reduce the cell's capacity by reducing the amount of active material in the cell. Eventually, the corrosion can get so bad that the cell just falls apart. Batteries designed for high output amps, like car batteries, have to have thin plates to maximize the surface area exposed to the acid. Thin plates make plate corrosion more of a problem.2. Freezing. If the battery's state of charge is low, it can freeze. The ice expands and wrecks everything. If the battery is fully charged, the freezing point is so low that you probably don't have to worry about it. Note that some batteries are designed with an acid concentration that is low enough that it will freeze. These batteries are only intended for indoor operation.3. Obvious mechanical insults like dropping, hitting the battery, etc. Lead is soft and heavy. It will break, twist, shear, etc.Because of all these potential problems a particular battery may or may not respond to an Epsom salt treatment - if the basic chemistry even makes sense. There's also the question of what are the performance characteristics of a treated battery? Cranking amps? Capacity? Freezing point?I'd be worried about turning a dead battery into a weak battery that might let me down when I need it.EdP.S. Refilling a battery with Epson printer ink? Hmmmm

author: jogri
author_rank: Frequent Contributor
timestamp: December 16, 2020, 08:45:03 pm
content: Quote from: edpalmer42 on December 16, 2020, 07:49:18 pmProblem is, it doesn't. You want to get rid of/dissolve the lead sulfate, so you obviously have so much lead sulfate that it won't stay in solution and falls out to make the crystals. By adding more sulfate even more lead sulfate will fall out of solution... You have to lower the sulfate concentration to dissolve it, not add more sulfate (in the form of Epsom salt, magnesium sulfate). The addition might have some secondary effects (lower resistance bc of saturated sulfate solution), but it won't fix the sulfation problem, it'll just make it worse.

author: Refrigerator
author_rank: Super Contributor
timestamp: December 16, 2020, 09:14:13 pm
content: It will lower the internal resistance of a sulphated cell but will not restore the original capacity, only a little bit.That's what i've found from my experiments.

author: coppercone2
author_rank: Super Contributor
timestamp: December 17, 2020, 01:28:14 am
content: I think I got some life out of batteries that way before but I think if you add too much epsom you poison the cell, so its gambling

author: Red Squirrel
author_rank: Super Contributor
timestamp: December 17, 2020, 03:16:00 am
content: From what I understand it will work but very temporarily. I would not try it unless the battery is already shot anyway.

author: coppercone2
author_rank: Super Contributor
timestamp: December 17, 2020, 03:53:40 am
content: I had results that lasted a long while but I believe a different cell then the one that was suspicious broke after I added it. I think I did a little better then trickle charge for a long time after adding MgSO4. But I also want to say I might have just used filtered water and not distilled water and that broke it.What you might want to try to do is make some kind of weak solution and add it drop by drop after you attempt to power cycle the battery to slowly work it. It is alot of work but it is satisfying to restore. Useful power source to have a SLA battery in the lab, just make sure to put insulated crimps over the terminals when not in use (you can make a 'protector' by crimping two insulated crimps over some paracord to keep them together). I blew up a pick that way. I had it at least for a few months but that was a sorry ass battery to begin with.I think right angle insulated 0.187 crimps are the best for SLA battery terminal protectors, so long you wrap them in tape (the side is open).

author: Rick Law
author_rank: Super Contributor
timestamp: December 17, 2020, 05:29:41 am
content: Thanks for all the comments so far. Please keep them coming.This battery restoration "project" is just to satisfy my curious and a chance to learn something. I have four defunct UPS and booster pack batteries that have been out of commission and left laying around for years. If I can restore them to say 50%, I'd call that a success and may find some use for these dead weights.If I do learn some ways to meaningfully improve a dead/weak battery, I may apply that to other batteries that is of use -- but for now, my main objective is to learn.Quote from: coppercone2 on December 17, 2020, 03:53:40 amSo far, my success is in trickle charging also, but my refill was with battery acid (they were pretty much bone-dry). Initially with normal charging, 3 of the UPS batteries goes from 2V-ish to full in milliseconds, then self-discharge back to 2V-ish within seconds. Two (after trickle charging at 13.6V for a couple of days) are now is holding a small charge. The third one which I carelessly left it trickle at 14.5V over night. It seem to be stone dead now.After seeing trickle charge did something positive with the UPS batteries, I applied trickle charging to a car battery that I want to keep. Initially, it too was 2V-ish to full in milliseconds, and self discharge back to 2V-ish in at most a couple of seconds. This time, I left it trickle for days (> 1week) at 13.6V. Seeing that it held the voltage (>12.7 volt) for over a day, I put that in the car and it started the car three times in a roll, each time immediately shutdown after starting. Just to push it further, I turned on the head lights, fog lights, interior lights and radio for 20 minutes to kill some charge before I try to start the car the forth time - and it start the car a forth time. I was going to test-drive it, but weather didn't permit. So, I'm not sure that battery can charge normally yet. I have more experimenting to do there. This one as I said I want to keep, so I wont do risky experiment with it unless the method is proven.Making this car battery better is not the objective of my "project", it is the motivator. For this car battery, not making it worst is the goal.

author: coppercone2
author_rank: Super Contributor
timestamp: December 17, 2020, 05:58:36 am
content: you need to take it apart and check for shorted cells though, carefully, then close it. Gluing it back is hard because its polyethylene, you need glue that can bond low surface energy materials and is also chemical resistant. acrylic epoxy might work. Don't charge it with the cover loosely on because the valves don't work right and they will pop off, you need to weigh it down with a brick from the top.

author: edpalmer42
author_rank: Super Contributor
timestamp: December 17, 2020, 06:02:58 am
content: If you're working with something like an AGM battery, that's a completely different situation. There isn't nearly as much liquid in an AGM cell as in a flooded cell battery so Epsom salts will have an even harder time accomplishing anything.Another questionable technology you might want to investigate is desulfators. There are lots of DIY circuits around. They're almost as controversial as Epsom salts!

author: james_s
author_rank: Super Contributor
timestamp: December 17, 2020, 06:48:36 am
content: I've gotten some minor improvement out of AGM batteries by adding distilled water, usually there is so little liquid that they become bone dry. It was never enough to be worth it as more than an experiment though.

author: Refrigerator
author_rank: Super Contributor
timestamp: December 17, 2020, 12:49:39 pm
content: Quote from: Rick Law on December 17, 2020, 05:29:41 amThose are AGM batteries and when they sulphate they do so very rapidly and in the process also completely ruin the plates.I've had AGM batteries that sulphated so much that they even blew open from the amount of white powder inside.I have one of those UPS batteries that is only lightly sulphated on one cell yet the cell is still nowhere near the performance of other cells, even after magnesium sulphate treatment, and gets abused when it discharges quicker than other cells.

author: G7PSK
author_rank: Super Contributor
timestamp: December 18, 2020, 03:50:31 pm
content: A few days ago I tried one of those pulse battery chargers on a deep cycle battery that had never been used but had sulphated trough age. There was a very loud noise from the garage late at night and the alarm went off.When i went to investigate the garage reeked of sulphuric acid with everything covered in the acid and the battery was completely demolished.I have never seen a battery blow up so completely and I have seen a few over the years.The charger had also been thrown across the garage with the plug being ripped out of the wall and the casing Brocken. I have tried other remedies for sulphated batteries in the past without much success and this pulse charger is the worst one I have ever tried.In future I will just recycle the batteries it is cheaper in the long rub.

author: coppercone2
author_rank: Super Contributor
timestamp: December 18, 2020, 07:31:38 pm
content: https://www.henkel-adhesives.com/at/en/product/structural-adhesives/loctite_aa_3038.htmlthis might be good for the top plate.the battery above is the reason why I make battery boxes for my batteries with giant steel vent grates painted to automotive finishI wonder what equivalent of firework it would be equal to for testing

author: james_s
author_rank: Super Contributor
timestamp: December 18, 2020, 07:44:16 pm
content: Quote from: G7PSK on December 18, 2020, 03:50:31 pmYikes!Goes to show that even boring and generally robust lead-acid batteries can go very, very wrong. Always wear safety glasses when working with them. Hydrogen is potent stuff.

author: coppercone2
author_rank: Super Contributor
timestamp: December 18, 2020, 08:24:21 pm
content: for a lab battery its a good project to make a housing with fuse and terminals

author: tcsaba101
author_rank: Contributor
timestamp: December 18, 2020, 09:53:40 pm
content: Quote from: edpalmer42 on December 17, 2020, 06:02:58 amI had some success in flooded lead acid batt rejuvenating in the last years. Not in other battery types.I found some rules what may help some of you.Anyway, the basics are written down almost 100 years ago:https://www.powerstream.com/1922/battery_1922_WITTE/battery_WITTE.htm#tocPulsers have to install on the battery in early stage, this is a prevention tech, not a cure (but sometimes worked)! Preventing to build up sulphate layer on the lead surface.I found this company's products the best:http://www.megapulse.de/.The main problem is the low charging voltage, what in some cars 13.8V. The charging should go up to 15-16V of course at low current, that can solve the sulphates on the lead surface.The installed pulser only works when the batt voltage is >13.5V, and makes 20-50V short pulses what is handling the sulphates effectively.One of our forklift is working for 10+ years and the battery is still fine, of course it needs maintenance.One pulser can handle the battery of two cars, forklifts, if you change on the batteries regularly.About dead batteries as mentioned earlier in this blog, mechanical or chemical damage can be the issue.When no mechanical damage, there is some hope to rejuvenate if the battery has had low cycles.The lead acid battery lifetime is about 700 cycles average.But if the cycle data is not clear, I have found some tech to find out whether a battery have some hope or not.1. Inspect mechanical status and if you can check cell voltages do it, if no visible issue, next step.2. Use a CV, CC power supply, and set CC= Capacity/100 current or less (in case of an 50Ah battery, CC<= 500mA), CV= 15.5V, and charge the battery.3a. If it reaches the CV within a week, there is a hope, discharge to 11V and repeat the charge>discharge 2-3 times, that will handle the sulphate, and the battery may works for additional 1-2 years, the pulser will help.3b. If never reaches the CV then you can try epsom salt, or other miracles....As I experienced the 10% of batteries can be rejuvenated, the younger the battery, the chance is higher.It is forbidden by law to make rejuvenating commercially in my country, but as a private I can do.

author: Rick Law
author_rank: Super Contributor
timestamp: December 18, 2020, 11:11:48 pm
content: Quote from: G7PSK on December 18, 2020, 03:50:31 pmWow! I was expecting blow-ups to be merely large cracks with some spraying. This one you got looks like it was worked over by explosives.Do you have a suspect? Since you said "this pulse charger is the worst one I have ever tried", is that your suspect? Hydrogen build up perhaps? Shorted?I am thinking of experimenting with those low amp/frequency pulse desulfator (not charger). Thus far, when I charge these old defunct batteries, I have been careful about making sure that the battery is vented and the cover held down only by a rubber band so hydrogen pressure can escape fairly easily.I've found a research paper on the web, they have good success pulsing high freqency at 140A. I am hunting for that paper again since I did not note the source.This is giving me a second thought. Perhaps I should wait till spring time so I can do it in a bucket in the backyard, or find something else to be curious and to experiment with.

author: james_s
author_rank: Super Contributor
timestamp: December 19, 2020, 01:53:18 am
content: That was a hydrogen explosion for sure. I don't know what set it off, maybe a broken connection sparked? I'm sure what happened though is electrolysis released a mix of hydrogen and oxygen which would be in perfect proportions and something ignited it causing an explosion.

author: coppercone2
author_rank: Super Contributor
timestamp: December 19, 2020, 02:07:53 am
content: was that a SLA or a wet cell?I think SLA is safer because the stuff inside of it dampens the explosion

author: G7PSK
author_rank: Super Contributor
timestamp: December 19, 2020, 09:15:04 am
content: It was a wet cell, a deep cycle Yuasa brand which was never used as it was purchased about 15 years ago for a wind turbine project there was four originally but it was decided to go with some large single cell batteries of 2.5 volt each and 900 amp hour. Three were given away years ago and this one kept and put on charge about once a year this time around it would not take a charge so I purchased one of those pulse chargers. I would not be surprised if it was the pulse charger that popped first setting off the battery. The pulse charge was a Chines made switch mode affair so it is more that likely that a cap. exploded and acted as a detonator for the battery.Last time I try to recover a smallish lead acid, big ones yes I can take them apart wash them out and scrape the plates if required.

author: Red Squirrel
author_rank: Super Contributor
timestamp: December 23, 2020, 02:52:37 am
content: Quote from: G7PSK on December 18, 2020, 03:50:31 pmWoah that's pretty crazy. I do wonder as well if this was a hydrogen explosion, though I would not have thought a single battery would produce enough at a fast enough rate to get that catastrophic. But yeah if the charger failed in some way where it was delivering line voltage to the battery or something, I could see it. The hydrogen would build up inside the cells and escape out slowly, then some source of spark ignited it.

author: floobydust
author_rank: Super Contributor
timestamp: December 23, 2020, 04:40:46 am
content: A common lead-acid battery charging tragedy is a shorted cell. If you originally read open-circuit voltage under 10V, you have to be careful.Chargers will act as if the battery is dead and pile on the current, bulk-charging. Then after a while, the remaining cells get overcharged and gas, end-of-charge is never reached.It also frequently happens in UPS as the gel-cells age and a cell shorts and then the remaining cells are overcharged and roast, the case bloats out, until cells dry out and the battery goes open-circuit to protect the server room from blowing up lol.A smart charger will start off applying low charging current until the battery voltage comes up to nominal 1.94Vpc (11.6V) before going into high current bulk-charging. Even DIN 41773-6 etc. miss this important test. A battery with a shorted cell rarely will make it to that high a voltage. A good charger also keeps track of coulombs because putting in say double the Ah rating into a battery indicates trouble, more-so after the battery was already charged up like in a UPS.Hydrogen requires the smallest ignition energy, pretty much the easiest gas to light up as well as acetylene. At 12VDC it's about 3A. But at 24V only 0.15A, and 50V 60mA so a pulse-charger might be a dangerous idea with a really old battery.I would say the battery may have originally had a shorted cell or badly sulphated, so it's just a hydrogen generator. Some pulse chargers dump as a boost-converter into the battery and high ESR would let high voltage spikes into the battery, then any spark will ignite inside. Or later it must have developed a new short and a lead flake made a hot spot to light up the gas.Anyhow, really bad to have the battery ignite, super dangerous

author: james_s
author_rank: Super Contributor
timestamp: December 23, 2020, 04:43:00 am
content: It has to be hydrogen, there's nothing else flammable in a battery. I'm actually not all that surprised, I've put electrodes in soapy water and held a flame to the little bubbles of hydrogen and oxygen that form and a bubble about the size of a pea makes a bang that will spray water in your face if you're not careful. It's not just hydrogen you get when you put electricity through water, it's hydrogen and oxygen in a perfect stoichiometric mix. I doubt the charger was malfunctioning, it just gradually created hydrogen and over the course of a few hours it was enough to fill the space. What set it off I don't know, but the result is not surprising.

author: Red Squirrel
author_rank: Super Contributor
timestamp: December 23, 2020, 04:52:23 am
content: I've had several of my Crappy Tire batteries die to a shorted cell. Normally what happens is I start getting hydrogen alarms (still at a safe threshold at that point) so I go investigate by touching all the battery cells and will find one that is warm. That is usually the culprit.I'm down to 3 batteries now as I stopped replacing them, when I'm down to just 2 or even 1 I will probably look at replacing with Surette golf cart batteries instead of marine, hopefully those will be better.Basically when a cell is shorted, it's like if the battery is now a 10v battery instead of a 12v as it will have 5 working cells instead of 6. You could in theory use it normally if you had equipment that is 10v such as a 10v charger and other things that can run on 10v. Not that you can really buy stuff like that off the shelf. The shorted cell itself will be a write off and you'd probably want to find a way to jumper it to create a higher amp rated path but if you caught it fast enough the other cells should be ok. If you did not catch it fast enough then the other cells will have been overcharged and probably be dead too. The overcharging part is what will be generating so much hydrogen. Though the shorted cell will probably generate a ton too until it goes flat.

author: james_s
author_rank: Super Contributor
timestamp: December 23, 2020, 05:04:57 am
content: Years ago I drove my car with a shorted cell in the battery for about 3 months before I got around to replacing it, never occurred to me at the time that it would be dangerous, glad nothing happened.

author: Red Squirrel
author_rank: Super Contributor
timestamp: December 23, 2020, 05:05:21 am
content: Also just remembered I need to test my hydrogen sensor as it's been a while. The way I do this is a little sketchy, I place a cup of salt water on top of the server rack and put two electrodes in it, plug it into a GFCI outlet. The alert will show up on my alarm screen within a minute and come on my phone within the next polling interval.There is probably a better way of doing that, but good enough for Canada, and leaves enough time to go out for a rip eh.

author: Rick Law
author_rank: Super Contributor
timestamp: December 23, 2020, 05:52:03 am
content: Quote from: james_s on December 19, 2020, 01:53:18 amQuote from: Red Squirrel on December 23, 2020, 02:52:37 amYou need a lot of energy to do this damage, so I wanted to understand it. I've been chewing on it since I saw that photo...I think two events are at work. Hydrogen and Oxygen mix is ignited causing a rapid energy release (explosion part), followed by an implosion since water takes far less volume than its composition hydrogen and oxygen when separated. It would be bending the casing outward, then as rapidly bending (sucking) the casing inward. What the explosion weakens or broke, the implosion would finish the job and tear it apart and blow it away.That's what I can think of, but I am no expert. Hope there is one with a more accurate/better explanation.Learning from this: Venting... It is far more importing than I originally considered.

author: G7PSK
author_rank: Super Contributor
timestamp: December 23, 2020, 08:40:19 am
content: I dont think there was a shorted cell as the battery had a high resistance from sulphating it had never had any load as it was an unused one and there is no sign of sludge at the bottom of the cells, not that I could have seen any before the battery blew up but there was no indication of sludge from the explosion and no sludge in any cell afterwards. Whenever I have had batteries blow up in the past it has always just been an end cell nothing like this one.As some has said it could be that the switching charger went short and put the full 240 volts through the battery, I will have to get the charger out of the scrap and try testing it.

author: james_s
author_rank: Super Contributor
timestamp: December 23, 2020, 05:59:34 pm
content: I would bet that what happened is an open circuit developed somewhere and the current from the charger created a spark when the circuit opened or perhaps multiple sparks from an intermittent connection. I had a car battery go open circuit just a few years ago, it was fine when I parked the car one day then I got in to go to work the next morning, turned the key and nothing, later testing showed it was completely open somewhere internally.A mix of hydrogen and oxygen is extremely explosive, try it with the soapy water like I did and see for yourself, the tiniest bubbles will make a snap similar to those "pop its" things you throw on the ground and they go bang. Larger bubbles will make quite a bang, and the volume inside a battery like that is orders of magnitude larger. A party balloon filled with hydrogen/oxygen mixture might blow out the windows if it ignited inside a closed room. It's really powerful stuff. If it wasn't so trivial to make you can bet it would be outlawed.

author: coppercone2
author_rank: Super Contributor
timestamp: December 23, 2020, 06:01:40 pm
content: it has low density so its not very destructive compared to outlawed things

author: floobydust
author_rank: Super Contributor
timestamp: December 23, 2020, 09:57:59 pm
content: What's interesting is the source of ignition. You can't ignite much of anything with only a 2V spark. That leaves heat, hydrogen needs 500°C (932°F) so I am thinking a short happened in a cell, from a glowing lead flake? The battery doesn't look that bad though.I see badly sulphated batteries just boil away, they don't do much else. This agitates all the corroded pieces. Within a cell, large gas bubbles form under the plates and then come up. I have a habit of tilting a battery to burp all that. But ignition at the bottom you'd think would blow out the bottom. Hmmm the second cell from the left has a bent up interconnect, all others are fine.It would be good to know the charger model to avoid the whole idea.I think pulse-charging is pseudo-science, lead sulphate crystals are stubbornly bonded to the plate's pores and after 100 years nothing has really cured it.Quote from: coppercone2 on December 23, 2020, 06:01:40 pmIt's the acid spray that makes it extra destructive, to eyes and things.

author: Rick Law
author_rank: Super Contributor
timestamp: December 24, 2020, 02:01:55 am
content: Quote from: floobydust on December 23, 2020, 09:57:59 pmIf it isn't too much trouble, I like to know what charger too.I was in the market for a charger, I went to my local auto-parts store only to see they are selling the same stuff I could get from Amazon or eBay/AliExpress.Trouble with cheap stuff proliferating. Paying a higher price means just paying a higher price but not necessarily better quality.

author: james_s
author_rank: Super Contributor
timestamp: December 24, 2020, 04:49:24 am
content: Quote from: floobydust on December 23, 2020, 09:57:59 pm2V? If a cell goes open circuit you have the entire open circuit voltage of the charger, which in the case of one designed for de-sulfating could be pulses of 100V or more. If you have current flowing through a circuit and you open the circuit it doesn't take much voltage to make a spark, shorting the output of a 1.2V NiCd cell will make sparks.

author: floobydust
author_rank: Super Contributor
timestamp: December 24, 2020, 05:48:20 am
content: Quote from: james_s on December 24, 2020, 04:49:24 amI'm using the IEC 60079-11 spark tables for hydrogen ignition energy values. I assumed it was a short within a cell that lit up the gas, not an open circuit. I don't see enough corrosion to cause an open circuit in the interconnects. They're built for 100's of amps for cranking.Maybe at some time in storage it had frozen? That breaks everything up.Nobody uses epsom salts or pulse chargers in the third world.

author: G7PSK
author_rank: Super Contributor
timestamp: December 24, 2020, 08:29:14 am
content: Up until the late 1970's there was a company in Cambridge (Cambridge battery services) that repaired lead acid batteries as long as they were the rubber cased variety with the top sealed in with bitumen,they would not repair the plastic cased ones that were coming in at the the time as they could not open or re seal them, from that bit of film it would seem you can, but the old elf n safety would have a fit if they saw that.

author: MIS42N
author_rank: Frequent Contributor
timestamp: December 24, 2020, 10:22:23 am
content: Fascinating video. When you think about it, a lead acid battery should be fully recyclable. When it is dead, all the acid and lead are still there as lead sulphate. The case is reusable. With a little bit of ingenuity I think someone could design a battery and a recycling machine so dead batteries go in one end and rebuilt batteries come out the other end. It annoys me that a dead battery may fetch a few dollars at a recycle yard and you then buy back all the same ingredients for hundreds.I have tried various rejuvenation methods and sometimes it works and most times it doesn't. Isn't worth the trouble. Lithium batteries are OK if you are looking for size and weight savings but for deep cycle stationary use lead carbon is good. Not much more expensive than AGM but 4000 deep cycles - that's over 10 years in an off grid system. Even better are liquid NiCd batteries, almost indestructible. I have some that are 25 years old and still good (2.4V @ 415Ah, weigh 50kg). I'd like to see the adoption of liquid metal batteries for grid storage - very long lifetime (nobody knows how long). Only problem they have to be hot to work - probably no good for domestic use.

author: james_s
author_rank: Super Contributor
timestamp: December 24, 2020, 07:03:18 pm
content: The batteries are fully recycled, I don't remember where but I saw pictures of a recycling plant where they had a huge machine that the batteries were dumped into which would grind them up and separate them into the raw materials. It probably makes more sense to do it that way and ship the raw materials to a plant that makes batteries than to try to tie it all into one operation but I don't really know.Either way it takes a lot of effort to break them down into raw materials and purify those, then turn those back into battery parts and then you have to ship the completed batteries around which being so heavy probably accounts for a substantial portion of what you pay for a new battery. Imagine how much a truckload of car batteries weighs and how much fuel it takes to carry those around to retailers.

author: G7PSK
author_rank: Super Contributor
timestamp: December 24, 2020, 07:29:28 pm
content: No idea how good the recycled batteries in that video are but the one that Cambridge battery services turned out were not as good as brand new ones, the plates they made were packed by hand and were just not as hard or robust as the one coming out of factories such as Exide or Oldham etc at the time.

author: Rick Law
author_rank: Super Contributor
timestamp: December 24, 2020, 08:05:57 pm
content: Quote from: MIS42N on December 24, 2020, 10:22:23 amIndeed interesting! A lot of work. In the USA parlance, it would be beyond even a re-built. It would be a re-manufactured battery since every part was attended to. It was so much work done there that if done in the USA, the cost of labor and parts/material would far exceed the price of a new battery.Quote from: MIS42N on December 24, 2020, 10:22:23 amI am nearing that conclusion as well. Seeing some of the "so very simple to do" videos on youtube, I just want to see what can really be done.I am arriving at: if trickle charge doesn't do it, that's it... almostIn my web-search based research, I found twoarticlesresearch papers showing pulse-charging works. Pulse-charging is beyond what I can do, but I found some "self-powered" pulser. Just clip it on the battery and powered by the battery, it send pulses back to the battery.Per my research, these self-powered pulser pulses too slow and with too little power to do much. Since I do have 4 UPS/BoosterPac SLA's at hand, I'm going to try that and see if it does anything meaningful at all. Once I get it, I will start with my tiny 7AH battery. Right now, it self-discharges to 4V-5V quickly.Quote from: floobydust on December 23, 2020, 09:57:59 pmThe exploded batteryG7PSK's posted has damage way beyond my expectation. I have been chewing on that. I want to understand it.I am arriving at this theory:Hydrogen may be a contributing factor, it may even be the trigger, buthydrogen (ignition or not) is merely a contributor but not the main source of energy of the explosion. It is the steam pressure.Pure sulfuric acid has a boiling point below 150 C. Battery acid is diluted so the boiling point is lower. Even 150 C is not hard to reach. Once it reach boiling point, boiling will turn all the liquid into gas rather quickly. True that as pressure increases, boiling point increases. But the energy injected into the system by the "charge" current can likely continue to push the temperature up enough to continue the boiling for some time. Plastic separator between cells is not good a thermo insulator. Neighboring cells would likely heat up and join the party. Between boiling and electrolysis, the pressure can build up rather high if there is no vent to release the pressure.Steam has the ability to blow up steel-boilers in a steam engine, it sure has no difficulty creating damage commensurate with what is shown inG7PSK's posted picture.This is my theory and of course I don't know if I am right... My gut feel is hydrogen ignition is not enough. The scale of energy of steam matches my gut feel a little better.EDIT:1. Corrected the wrong quote. I inserted the wrong quote in the reply when I first saved.2. Changed the wording "articles" to research papers. They were not merely someone writing an article for a magazine but serious research paper. One from IEEE, and another from 2017 IOE Graduate Conference.