10 year old rechargeable acid battery - Page 1
Forum section: electronics / general

author: vinlove
author_rank: Frequent Contributor
timestamp: March 17, 2023, 01:55:35 pm
content: I just took out this old battery from the casing of originally what used to be a car engine jump starter.It used to be recharged for 13.8V, and used to output the DC to power the other electric gadgets giving out 12V, 9V and 3V.It is about 10 years old. Now it was not charging well at all. It would try to be recharged, and then the fully charged light would come on.When it then connected to any device, it would return to LOW power mode immediately.Today I disassembled the casing, and there was this acid battery rated at 13.V. When measured the output voltage of the battery with DMM, it reads 9V.Could this battery be used for 9V? Is there a way to revive this battery? Or should it be discarded?I am going to order a new acid battery of 12V 9AH from Amazon, and connect it to the old jump starter, because it has all these buttons for charging, and outputs for 3, 6, 9, 12V (cigarette socket output).

author: Rick Law
author_rank: Super Contributor
timestamp: March 18, 2023, 04:54:47 am
content: I am no expert, but I have experimented with battery revival half a dozentimes. This is not an expert-opinion but merely sharing my non-expert insights from thosefruitless efforts.Car jumper battery is probably SLA (seal lead acid) or GEL. 12 volt is actually 6 battery lead acid cells in series each of 2 volt. So 12V car battery is a battery pack consist of 6 cells. My understanding is GEL and SLA are similar in the way they work except for how the acid is "held" inside the cell, as a gel or as a liquid.When it is below 10V, you are more than 2V from 12V. When you have only 9V, likely, the weakest cell is stone-dead, and at least one more cell is below 2V. The dead cell(s) will work against you when you try to use the remaining "working" ones. (see notes at bottom if you want to know how it work against you.)In my tests in trying to revive 1/2 dozen of old SLA's (three are from car-jumper packs), the other three from UPS - all are SLAs (not gel) based on visible fluid presence. All but one were dead for > 1year. Some holding voltage at 5v ish, some holding below 2v. The best dead one was last known to be alive and charged about a 1 year ago (before date of attempted revival). That one was holding voltage at 10-10.5v.- For some, slow (drip) charge often bring it back to 12V. it could hold some charge, but single digit percent of rated. Best case I got from the not-too-dead one (rated at 22AH) was below 1AH.- for some, it may rise to 12V in mere seconds. It is because the charge it can hold is low so it is "full" quick. Like a gas thank full of rocks, you can fill the tank quick but holds little gasoline. With just a small charge, it drops back to way below 12V really quick -- in sub-second or within seconds when discharge started, it is done discharging (my worst was under 1V, so all cells were dead - upon disconnect of charge cable, self-discharge will bring it back down to 1V within minutes).- Renewing the battery acid (you can buy that at auto stores) doesn't help... reason below later- Acid in the battery is sulfuric acid, around 50% pure sulfuric acid if memory serves. Discharged battery start reacting and deposit the sulfur on the lead plate. De-sulfation with those "pulse desulfator" modules does work but just very very little - it gives a flash of life (a few percent more) for a cycle or two than back to darkness. Further de-sulfation will do less and less... same reason, below- It appears to me that the lead-plate is too well coated with sulfation. Pulse is not going to "break it up". One could consider sanding it off (as some battery re-manufacturers may do), but that is an extensive job and a rather dirty one. Then there is also the consideration: is there enough lead still left on that lead-plate to be useful.So, all in all, it is not worth the effort. My best was "revive" a 22AH rated battery to give me less than 1AH (At below 10.5V, I terminate and sum up the numbers), but it would be easier and more predictable to use a few AA or 18650 batteries for that.Notes: How the dead cell work against youIf you want to understand how it works against you: Draw a diagram of 6 cells and a load (so 7 boxes) with a line joining the boxes and the load in a circular chain, write down the + and - on each box that represents a cell. Now follow the current in the circle, you will see that on a dead cell (regardless of which one of the 6 you pick as bad), the current flow for that box will be reverse charging it. It can't do much "push against you" since it has little charge, but it certainly will "resist" your effort.The old post here I wrote on that desulfation test:https://www.eevblog.com/forum/chat/trying-out-battery-desulfator/Edit: Reviewed my old thread and correct a few numbers I type here. (Number typed here came from memory whereas the old tread was from actual notes at the time, so the old one is accurate). Yes there were 6 total. My old thread said 3 because the other 3 is so "stone-dead" I did not seriously tried to revive them. It did get the desulfation but no serious notes was taken after seeing how little charge it held.

author: vinlove
author_rank: Frequent Contributor
timestamp: March 18, 2023, 03:05:54 pm
content: Great explanation on the topic - thanks !!I started charging the 10 year old lead acid battery taken out of the car jump starter casing with my lab power supply rated at 10A, 1V - 30V.When the PSU was set to 13V, and connected to the old battery, there was nothing on the amp display on the PSU, meaning it was not charging at all.I slowly increased the voltage to 15V, 17V, and still nothing, but when it is 20V, there was amp reading 350mA. So it was charging at 20V, and drawing 350mA.I then decreased the voltage to 14.8V, and the amp went down to 150mA. I thought that would be about good amp reading for the slow recharging.And it is charging at that right now - I will leave it for about 24 hours and until the amp reading decreases to 0mA.It seems the old 10 year old lead acid battery needed some kick off with the higher input voltage around 20V, and it started recharging, and showed the sign of life. I have already recharged another old Lead Acid battery this way, and it seems now working OK, so I am following the exact same method. Will update how they will run - they may only work briefly and fail or die again. I am not sure at the moment. But if they keep working good again, then it will save me buying new batteries at about £20 - £25 each.

author: Seekonk
author_rank: Super Contributor
timestamp: March 18, 2023, 07:55:56 pm
content: If you pry off the sealed plastic cap there will be one way rubber plugs on each cell. Common failure is the gell dries out. I have recovered a small number of these by removing the caps and adding distilled water. Allow at least two days before attempting any charging. There is no recovery from severely sulphated plates.

author: vinlove
author_rank: Frequent Contributor
timestamp: March 18, 2023, 10:09:14 pm
content: Although it looks like it is charging OK, I have little faith that the battery will work like NEW.I am not too keen on opening up the acid battery box.If it does not work well, it will be discarded, and the new ones need to be bought.In that respect, maybe it would be better going for the Lithium or Li-On rechargeable batteries (more expensive) rather than the lead acid ones?I am sure Lithium / Li-On batteries have their disadvantages too.

author: Rick Law
author_rank: Super Contributor
timestamp: March 18, 2023, 11:21:54 pm
content: Quote from: Seekonk on March 18, 2023, 07:55:56 pmThis reminds me, when I last pop the plastic top, I can see the fluid and measure individual voltage of each cell (via some arithmetic). If I pop the next-lower cover, I may be able to get to the inter-cell connections. From there, it may be possible to use the remaining good cells.Assuming the 9V cell has just two bad cells (instead of all "kind of dead"). For the bad cells, I short the bad cells' +- nodes with a wire of appropriate size, that bad cell is by-passed by the short. So in theory, if that 9V SLA has two dead cells and the other 4 is still serviceable, I can find out which two cells to by-pass and I end up with a good 8V SLA. But then of course one would need a custom 8V SLA charger. All just to keep those remaining "already in hospice" cells working...

author: vinlove
author_rank: Frequent Contributor
timestamp: March 19, 2023, 11:25:37 am
content: After almost 20 hours of charging, it seems still charging, and the amperage has increased to 400mA. When it gets recharged to near the charger voltage, the amperage drops to 1 - 0 mA, but this battery has increased the charging current after 20 hours of recharging. This is an unusual observation for me.The other LEAD ACID battery 12V and 7AH rated almost same age as the above, has gone through the same recharging process, and it is sitting at 11.7V which is near enough for what I need 12V. It powered my old shortwave radio running at 12V very nicely last night. It ran for over an hour, and the voltage was holding up OK. This morning, it was still keeping the output voltage at 11.5V.

author: Rick Law
author_rank: Super Contributor
timestamp: March 19, 2023, 07:06:57 pm
content: That also happened to those old SLA's I was play with --see alert belowI think the cells just had it andthe charging power is now merely power to disintegrate the cell further or boiling off the battery acid. A dead cell is not a functional cell, so one cannot expect it to behave normal. It probably no longer has the ability to be taken up to the normal full charge current.****** Alert *******Make sure you have proper ventilation and pressure relief.Pop the top cover and make sure that the rubber cap is loose enough to let air (hydrogen) out. The cover could be glued on with so little tight that the rubber cap doesn't have enough play to vent. Hydrogencan build up to dangerous level. If there is weakness on the cover, the battery may have a mini or even large explosion. After hearing one of my battery's rubber cap popped mildly, I removed the top cover and use a rubber band to hold it down - so I know pressure wouldn't build up but the acid sip out gently. I have the battery sitting on a plastic tray which I tested to be able to withstand battery acid.

author: vinlove
author_rank: Frequent Contributor
timestamp: March 19, 2023, 11:24:03 pm
content: I stopped recharging the old battery after about 24 hours - the current draw was still at about 400 mA. But I didn't want the recharging going over 24 hours. I measured the output voltage of the old LEAD ACID Battery just taken off from the recharging. It was 13V DC. It was good enough output voltage to power my old radios.The battery was reconnected to the casing which has all the outputs for cigarette light sockets for 12V ... etc.When it was connected to the old shortwave radio, and powered on, the radio sounded very nice lively with excellent sensitivity. It ran for about 30 minutes, and I switched it off. The unit's power level indicator was still GEEN light - which means good voltage and current level. I read the output voltage again on the recharged battery, and it was 12.8V. It is ideal voltage to run the 12V DC powered shortwave radio.This is an incredible improvement from the original state of the battery, which was refusing to be recharged, and even after hours of recharging, when it was connected to a device to power it up - it would just go flat.No, I didn't want to mess around with opening the lead acid battery casing dealing with the chemicals in them. I just wanted to see if they could be revived by some alternative metholds of recharging - and the high voltage of around 20V kick start at the start of recharging briefly with the variable voltage DC Lab power supply, and when the old battery is starting to draw the current, then adjust the recharging voltage just above the desired / rated voltage of the battery, and let it get recharged until the battery is not drawing any more current. It seems doing the trick.I will keep try using these old acid rechargeable batteries next few days / weeks, and update how they are getting on. It definitely saved me from spending £50 for the new 2x acid rechargeable batteries for now, and I am quite happy with that.

author: Rick Law
author_rank: Super Contributor
timestamp: March 20, 2023, 01:53:05 am
content: Keep it charged and it will keep working. It probably lost some capacity and some life (duration-wise), but if you keep it charged you can limit further lost.SLA doesn't like being in a discharged state. The longer it stays discharged, the more sulfation build up. When it gets discharged below 12V, time is the enemy. When it discharged to 0V, time is the killer.Funny that just within the time frame of this thread, I had to revive my 0V car battery. Left the interior light on during snow storm, and didn't notice for weeks till last Wednesday. I did exactly the same with this battery last winter... I think my battery may not survive another winter if I do that again.

author: james_s
author_rank: Super Contributor
timestamp: March 20, 2023, 02:18:00 am
content: I've never had any luck restoring old SLA batteries to usable condition, although it won't hurt to play around with it. Do be very, very careful if you pop the caps off to add water. Wear eye protection and don't stare down into the hole, they can spit acid in your face.

author: vinlove
author_rank: Frequent Contributor
timestamp: March 20, 2023, 10:00:34 am
content: Yes, this is kinda of experiment for reviving the dying old Lead Acid Batteries. These SLA batteries are quite awkward even when discarding - they are not supposed to be tossed into the domestic rubbish bin. They must be taken to the special location for recycling these things in the council designated recycle centre.So, reviving them would be double advantage if successful - saving the money for the new SLA batteries and also environmentally doing good to the planet, as well as saving time taking them to the recycle centre.Anyhow - my usage of these SLA batteries are not current hungry devices but to power the old shortwave radios run at 12V DC. I could just get the mains wall plug DC power supplies for 10 -20 £, but they tend to be noisy, which degrades the DXing capabilities of the radios. Some folks recommend linear PSUs with the heavy transformers - but these have potential problems of blowing up killing the radios by burning them - it happened with me before when using an old linear power supply. One of the old capacitors in the linear power supply blew up while powering the ICOM radio, and it burnt itself and also the ICOM radio. I returned the old psu for full refund, but the damaged ICOM radio was not saved. A big loss.Switching psu are flimsy and tend to be noisy (if not specially made for radios), but at least they don't seem breaking the devices powered by them, as they just stop working rather than exploding.

author: james_s
author_rank: Super Contributor
timestamp: March 20, 2023, 05:02:08 pm
content: You can get money for them at a scrap yard here, they pay by weight. It may not be worth the trip for one, but if you an find a few more it's worthwhile.

author: floobydust
author_rank: Super Contributor
timestamp: March 20, 2023, 06:31:47 pm
content: The battery is pooched, it's badly sulphated after the many years in a discharged state.I have encountered this many times. It shows up as the battery being mostly open-circuit, not taking a charge even with super high voltage say 20V (that's when the rotten egg hydrogen stink happens).The best recovery you can do is to charge it for days. But you still end up with a weak battery due to the sulphate buildup.I just take them to the Eco Center for drop off.

author: james_s
author_rank: Super Contributor
timestamp: March 20, 2023, 07:11:45 pm
content: I've taken a few old SLA batteries apart and they were more than sulfated, all of the negative (I think) plates had crumbled into bits.

author: floobydust
author_rank: Super Contributor
timestamp: March 20, 2023, 08:04:28 pm
content: It's a metal in an acid, who thinks that is going to last? Corrosion disintegrates the plates and interconnects. Or they dry out, or sulphate gets them.After reading research papers with SEM photos of sulphate crystal forming in a plate's pores, and that the crystals are an insulator (effectively reducing plate surface area) and there's no proven way to clear them... I no longer waste a lot of time hoping to rejuvenate lead-acid batteries.

author: vinlove
author_rank: Frequent Contributor
timestamp: March 22, 2023, 10:57:29 am
content: Yeah, they wouldn't be able to jump start cars at that state for sure. But for powering up Shortwave radios running at 12V DC, they seem to doing the job for powering them for a night per a few hours recharge for now.If they stopped even doing that, then sure they will be dropped off at the local supermarket, where they collect the used batteries.

author: Rick Law
author_rank: Super Contributor
timestamp: March 22, 2023, 05:32:11 pm
content: Quote from: floobydust on March 20, 2023, 08:04:28 pmI also went through a lot of research paper as well. Some claim very successful results. Hence I got a de-sulfator to try for myself knowing that unlike the research ones with high-power and sophistication, the de-sulfator I have is low power low feature so it is not likely to do much. Then there is the recent-dead or already fossilized dead. There is a point beyond hope.So my current approach is the following two steps, and if that doesn't work, that it.1. Slow charge and then soak for a day or two then test. Working is defined as normal charging and getting it tostore a useful charge. So far, from a new sample of two (not the original 6 really dead ones), I have only needed step 1.2. Since I already have the de-sulfator... With prior experience (results written in the prior thread, link in prior reply), I know it works a little. So I will use the de-sulfator again for a few days duration then do step 1. Repeat de-sulfation untill it stops improving significantly -- prior experience would make me guess it would be 3 to 5 runs. When improvement stopped and charge capacity is still far from useful, it is considered dead. So far, my "new sample of two" have not needed step 2 yet, sostep 2 is merely an untried but intended plan.My "really dead" original sample of 6, the best was the 22AH battery with capacity "improved to around 1.5AH". In thar prior thread, I said improvement was "measurable but not meaningful." While i can use it for emergency lighting. A 200mA LED during power outage is indeed welcome even if just for an hour or two. But it is not a "worthy amount" to be meaningful. Since SLA needs to regularly maintain the charge or keep it float charging. While maintenance float or drip charging a good battery is proven to be rather safe, I am nervous leaving a bad battery with little life left to "safely degrade" under power continuously. That is risk (and lots of hassle monitoring it) with very little gain.

author: vinlove
author_rank: Frequent Contributor
timestamp: March 22, 2023, 05:47:56 pm
content: Quote from: Rick Law on March 22, 2023, 05:32:11 pmRisk? SLA battery voltage always drops as it is used - it never rises. The device it powers will simply stop working when the voltage drops to below 10V (for 12V devices). What / how could it damage or harm?

author: Rick Law
author_rank: Super Contributor
timestamp: March 23, 2023, 12:17:00 am
content: The risk is typically not during discharge (assuming your connections and your load are safe). The risk is duringapplication of maintenance float or drip charge (or regular high-current fast charge) when something goes wrong.When one has a charger plug into the wall with power on and battery connected, real danger can occur. So I do "unattended charge" only for batteries in good condition. When in doubt, I monitor charging very closely.EDIT: decided to remove details about how some of my charging failed. My equipment is likely different than others so how my charge fail doesn't really matter.

author: floobydust
author_rank: Super Contributor
timestamp: March 23, 2023, 03:12:54 pm
content: During float charging, a common SLA failure is for a cell to short. You've now got a 10V battery and a charger will go high current and roast the other cells in the battery, until they dry out. It makes a lot of heat, I see batteries bulged out and leaked (especially in UPS but this might be from high-rate discharge through a bad cell).So float charging is not entirely safe.

author: vinlove
author_rank: Frequent Contributor
timestamp: March 24, 2023, 08:48:15 pm
content: Quote from: Rick Law on March 23, 2023, 12:17:00 amGot you. Yes I know what you mean. I was under impression possible danger during recharging only happens with the SLA batteries of poor physical condition such as bulging casing or leaking from the casing. Of course SLA batteries in that shape or condition must be discarded immediately.But the ones I have are in clean solid condition without any trace of leak anywhere. So I have tried revive them, but I can conclude that it is impossible to revive them into fully the original state. That seems the definite impossibility. But it could be revived into some sort of reduced capacity such as my old SLA batteries seem quite happy getting recharged for about 20 hours, and intermittent float recharging. When it is recharged, it runs at about 12.5V, and it can power very light current drawing devices such as the Active Antennas = it can run for hours and hours before the battery goes under 11V which need recharging. This is still something than nothing.Because I am running my shortwave receiver with a new Lithium power bank which outputs 12V via cigarette socket and a few 5V for USB recharging (This power bank was quite expensive at about £70). When both sw receiver and active antenna are connected to the power bank, it goes flat very quick. When the active antenna is powered by the old SLA battery, it runs for hours and hours. So it is still doing some good for my use. If it shows any sign of degrading in the output, recharging or the shape of the SLA battery casing, it will be discarded there and then.