Attempt 'rejuvenating' old gel-cell lead-acid batteries with a bench supply?

[floobydust]

...What?
Tim

Lately, the forum seems to have an effect on people's neurological processes.

I checked with my bookie for odds on this battery getting rejuvenated. Finding water on Mars was 22/1 years ago.
This battery down to 12.0V...  so he gave me 100/1 

[Armadillo]

I read.

After so much long hoo-ha, what appeared to be merely battery re-charging process as can be found in manufacturer datasheet and added with a bit of self-named merry go around here and there, doesn’t impress me.

The tests are flawed with too much hypes and personal over-characterisation. It lacks international references. It can be seen in #14, that the battery exhibited 6 ohms load on initial discharging, which means it is NOT THE RIGHT CANDIDATE. Which means, this long hoo-ha PROOF NOTHING.

For example [See pic], Manufacturer says for over discharged battery, to set current limit at 25V charge for 5 minutes for batt to recover after which they classified as “no good’. This should be the criteria for the right candidate to be chosen with Proper Qualification and Acceptable Undeniable reference made.

Furthermore, there must a Proper Referenced Qualification of the “Recovered Battery”. For this [See pic], the battery should hold the voltage above the pass threshold after 2 hours. Alternatively, this can be used as a Selection Candidate for the De-Sulphate Process.

Whether is 12K posting or 13K or 100K combined? The worse is disrespecting others and refusing to accept technical criticism.

100 shares and 50 goes to Susan, doesn’t impress me. Please bear that in mind.

[Armadillo]

This battery down to 12.0V...  so he gave me 100/1 

Hahahahahahaha  That's a good one.

If he can "rejuvenate" a "right candidate" to less than 1/100,  otherwise is a WASTE OF TIME pulling batt from the Jet-Ski in and out.

Hahahahahahahaa   

[floobydust]

There is a lot of research on sulphation using scanning electron microscopy to look at the crystals.

It appears the sulphate crystals are always forming on the plates. The size and effect of them always increasing. This is the reason lead-acid batteries are only good to say 500 cycles, have a limited life. It's the main aging mechanism.

If you leave a battery discharged for 1 day compared to say 100 days, the crystals kept growing in size and sulphate is an insulator- a non-conducting salt, insoluble and filling the lead plate's pores- so you can't get rid of them really.
We don't know how long OP's battery was sitting there dead.

[tautech]

There is a lot of research on sulphation using scanning electron microscopy to look at the crystals.

It appears the sulphate crystals are always forming on the plates. The size and effect of them always increasing. This is the reason lead-acid batteries are only good to say 500 cycles, have a limited life. It's the main aging mechanism.

If you leave a battery discharged for 1 day compared to say 100 days, the crystals kept growing in size and sulphate is an insulator- a non-conducting salt, insoluble and filling the lead plate's pores- so you can't get rid of them really.
We don't know how long OP's battery was sitting there dead.

Yes but sulphation is part of the battery chemistry, it doesn't work without it.
What is more important WRT sulphation is the type, some form very difficult to break bonds with the plates whereas others are migrated back into the electrolyte with ordinary charging or a gassing charge.
Still others can be partially addressed with high energy electrical pulse desulphation.

Battery construction determines what methods can be used to address sulphation.

[BradC]

This is the reason lead-acid batteries are only good to say 500 cycles, have a limited life. It's the main aging mechanism.

No it's not. It is however a significant contributor if the batteries are undercharged. You can effectively manage sulfation during the operational life by managing the charge profile, but the side effect of that is corrosion of the plates.
So an under-charged battery dies by sulfation. An overcharged battery dies by plate corrosion. Of course a battery that is kept exactly on spec (cool and with a temperature compensated charge voltage) will last longest, but ultimately barring a catastrophic failure it'll be a balance of plate corrosion and sulfation that drops its capacity past the threshold of usefulness.

Example, the Vision 55AH SLAs I have here are now 16 years old. They have a design life of 10 years (which is defined by having greater than 80% of their original capacity remaining). When I got them 2 years ago they all measured out (at their C/10 rate) above or on spec, but they had been *very* well looked after. After 2 years in service I'm just about due to cycle them and see how they are fairing.

[floobydust]

You can do 500 cycles over several months or do the 500 cycles over many years. I think the +ve plate corrosion is a slower aging mechanism in SLA, flooded PbCa grids seem to corrode quickly.
There are probably a hundred lead-acid battery failure mechanisms. Every paper I read has a different theory.

In practice I find an overcharged SLA dies due to loss of water, and really old SLA fail due to plate corrosion. In constant float-use like a UPS, 59% plate corrosion and 33% dry out = 92% of the reason for failure.

As far as sulphation, which I think OP is up against, it was a Reseachgate paper behind a paywall with scanning electron microscopy (SEM) showing the sulphate crystal growth progress and get larger with every charge/discharge cycle. They've been adding tin and graphene to hinder that, to get more than 500 cycle life.

OP's only remedy left might be a pulse desulfator. But these fall under the category of voodoo and hope. I built the cheesy 555 timer version and it did nothing. Lots of threads about it, one poster did an open source very high current pulser that seems to work.
https://www.eevblog.com/forum/projects/guess-what-will-happen-battery-desulfation-experiment/25/
https://www.eevblog.com/forum/oshw/desulfate-regenerate-lead-acid-batts-a-new-diy-guide-overnight/
https://hackaday.io/project/25741-desulfator-engine-re-climate-change-mitigation

I'm surprised your Vision batteries have lasted so long, that is remarkable. But how many cycles they have, their temperature etc. is also surely a factor.

I see many people now measuring battery ESR to determine health. It might be worth a try on gel-cells.

[CJay]

I see many people now measuring battery ESR to determine health. It might be worth a try on gel-cells.

ESR has been a 'thing' for determining battery health for some time, it works on gel cells too.

I was selling testers that used the ESR principle ~20 years ago, alongside load testers and slightly more complex units like the SPX ARBST (which was ancient at the time) for the nay sayers who didn't believe a battery could be effectively tested by something that looks like a cheap multimeter.

The results were more accurate from the ESR test but you needed to understand capacity, CCA rating, temperature effects etc.

The load testers were trivial, connect it up, watch the needle, if it goes into the green bit the battery is good, if it doesn't, sales opportunity!!

[tautech]

I see many people now measuring battery ESR to determine health. It might be worth a try on gel-cells.

ESR has been a 'thing' for determining battery health for some time, it works on gel cells too.

I was selling testers that used the ESR principle ~20 years ago, alongside load testers and slightly more complex units like the SPX ARBST (which was ancient at the time) for the nay sayers who didn't believe a battery could be effectively tested by something that looks like a cheap multimeter.

The results were more accurate from the ESR test but you needed to understand capacity, CCA rating, temperature effects etc.

The load testers were trivial, connect it up, watch the needle, if it goes into the green bit the battery is good, if it doesn't, sales opportunity!!

Generally from damage resulting from a carbon pile tester. 


Sir, your battery is sick.
Yes I know, you just made it way. 

[CJay]

Generally from damage resulting from a carbon pile tester. 


Sir, your battery is sick.
Yes I know, you just made it way. 
[/quote]

Indeed, fortunately we didn't sell the carbon pile garbage but they were still in use in a lot of workshops, scary things with sparks and destroyed batteries and battery terminals, the ARBST was gentler but...

[tautech]

Well I must be a tiger for punishment as a couple of big chunky 12V Optima Deep cycle yellow tops have found their way to me.
They're flat, really flat, each only a volt OC ! 
It's only that I hold spiral wound cell Optima batteries in high regard that I'm willing to give these a fresh chance at further usefulness.
These:
https://www.optimabatteries.com/en-us/yellowtop-deep-cycle-battery/d31a


Circlotron, are they worth the effort or am I  ?

I do have some new tools.....a shiny new Siglent SDL1020X-E 20A electronic load that I can set all sorts of fancy for nancy loads and discharge cutouts.

[Gyro]

Well I must be a tiger for punishment as a couple of big chunky 12V Optima Deep cycle yellow tops have found their way to me.
They're flat, really flat, each only a volt OC ! 
It's only that I hold spiral wound cell Optima batteries in high regard that I'm willing to give these a fresh chance at further usefulness.
These:
https://www.optimabatteries.com/en-us/yellowtop-deep-cycle-battery/d31a

Those look a bit of a bugger to clamp down, they certainly wouldn't work with the 'bottom skirt clamps in my car.

Having said that, I still have a bunch of Gates Cyclon wound cylindrical cells that I rescued from the bin at work where the alarm company had dumped them, nearly 30 years ago! Despite severe neglect since, they are still going strong.

Give them a nice long float charge at 13.8V.

[tautech]

Having said that, I still have a bunch of Gates Cyclon wound cylindrical cells that I rescued from the bin at work where the alarm company had dumped them, nearly 30 years ago! Despite severe neglect since, they are still going strong.

Those Cyclon were sealed but flooded IIRC weren't they ?

These Optima's were once solar and wind charged for a CB radio relay station that's fallen into disuse and sat neglected for a while.

[Circlotron]

Circlotron, are they worth the effort or am I  ?

Definitely worth a try! Those batteries are too good to just ignore.
Did that other battery you worked on stay somewhat good?

[Gyro]

Those Cyclon were sealed but flooded IIRC weren't they ?

Not sure about any excess electrolyte, I don't think so. They were (are) tightly wound AGM. The hidden resealable pressure vent doesn't vent until 50psi, that probably accounts for them holding on to their electrolyte.

https://www.enersys.com/EMEA/CYCLON_Batteries.aspx?langType=1033

[tautech]

Circlotron, are they worth the effort or am I  ?

Definitely worth a try! Those batteries are too good to just ignore.

My thoughts exactly.

Did that other battery you worked on stay somewhat good?

Nah not so good.
It's always struggled to hold charge/voltage and I've get to attempt to desulphate it but as winter kicks in I'll have more time to get back to it but I don't hold out too much hope for it. 
Still the process of attempting to rejuvenate it was well worth the learning experience and I thank you for the guidance offered while doing so.

I didn't mention the big gell cell I scored along with the Optima's as it was holding some 12V after who knows long neglect and that one was first on the charger and seems fine as it's charge has fallen away to low current overnight but still needs some load tests to confirm whether it's any good or not.



Todays job is to make some decent leads for my SDL E-load, do tests on this bad boy ^ and then properly flatten the Optima's in readiness for their reverse charge.

[james_s]

Lead acid batteries are really a mixed bag. I've had some that failed within a couple years that I had no success in bringing back. I've had others amaze me, one car battery I dealt with was 14 years old, I managed to bring it back after it had sat for around 6 years and was at 0V, took a full charge which amazed me. I worked on the car some, got it running then it sat for another 5 years while my dad looked for the paperwork. Battery was again completely flat, 0V, but to my amazement it again took a full charge. It was in good shape too, in the process of waking the old car from its long slumber I cranked the engine intermittently for 2-3 minutes before it fired up and it was still cranking at a good rate when it started. I've wonder if it largely comes down to purity of the materials.

[tautech]

Well I must be a tiger for punishment ..............

It's NOT true, I actually have a sickness...............batteries, the bigger the better !

Came home with 6 of these bad boys that need some work...........but as they're made in OZ the jury is still out on that. 
Quick check reveals ~1V in each cell.



Nice spot for them close to a powerpoint for charging and testing.
 




Still looking for info that exactly matches the model # but the pdf below is probably close enough.

[LapTop006]

Came home with 6 of these bad boys that need some work...........but as they're made in OZ the jury is still out on that. 
Quick check reveals ~1V in each cell.

Wow, haven't seen the BP Solar name in years. They were were common ~25 years ago in RAPS systems, but by the early 2000s were getting rare, at least in Australia. I just looked it up and the brand lasted until 2011/

[rsjsouza]

I am going through a similar self-punishment process with a Yuasa 12V/7Ah purchased new in 2016 but by negligence (my own) I let it go down to 3.7V. I also found a Amptek 6V/4Ah that seems much more promising - it had 6.2V total but a very high internal resistance.

I just found out this thread, thus I didn't try Circlotron method just yet. To me I have been cycling these batteries with a voltage charge of 2.4V/cell and the last charging cycle was throughout the weekend: 48h straight.

The Amptek seems to be holding very well, with 2.19V/cell at the moment. I have been discharging this battery using a EBD-Mini electronic load I got from Franky many years ago. The past discharge runs showed is as being pretty weak: 59mAh when discharged from the full capacity to 1.83V/cell (5.5V) at 0.1A.

The Yuasa is about 2.0V/cell after this weekend's 48h charge cycle, thus it probably needs a bit more "shaking".

For me this is just an interesting exercise. I am pretty sure that, if none of this works out, I won't be  but instead being thankful of learning something interesting. At the same time I have been exercising the logging features of my E36312A and both my U1273A and U1282A.

[CJay]

I've just revived a pair of 75AH Lucas SLAs from a mobility scooter, both well under a volt at the terminals after being sat for at least four years (last time my MIL used the scooter), initially they didn't take enough current to register on the analogue meter on my PSU, after a good few hours they began to take current, rising to 300mA, enough to persuade my 'smart' charger that it needed to provide current to them.

After six days they were holding a good charge and performed under a simple load test so I refitted them to the scooter and drove it.

For over an hour before I got bored.

It's now been a little over six weeks since I refitted them, they've had four charge cycles and they seem to be working just fine.

Well worth the effort give that they are approximately £160 each.

[rsjsouza]

I didn't yet try Circlotron's method on the 6-cell Yuasa, given the charge/discharge cycles on it are yielding an ever growing ramp that is currently at 2Ah.

The 3-cell Amptek was much less promising: it was peaking 150mAh (120mAh was the norm). After Circlotron's method (48h at negative 6.6V, then 48h at positive 6.6V, both at 100mA) I just finished the test on the electronic load and got almost 480mAh - still at 10% of the top capacity.

I'll try the rejuvenation method once again on the Amptek, but I think it will be binned if things don't improve.

At any rate, it is an interesting exercise.

[tautech]

3 weeks continual charging later....this gel cell reached full charge as in that another linear smart charger reported it as fully charged at 14.26V. After a few hours rest 13.12V.
Some load tests next to see how it behaves.

[RoGeorge]

Found yesterday a discarded 9Ah/12V UPS battery.  It was written on it "Maintenance-free Sealed Lead-acid Battery", which remembered me about this thread and Circlotron's reverse charging recovery method:  https://www.eevblog.com/forum/repair/attempt-rejuvenating-old-gel-cell-lead-acid-batteries-with-a-bench-supply/msg1985024/#msg1985024 , so I took it home out of curiosity to test the reversed charging recovery.

The battery measured 3.5V with no load, and took no charging current when trying to charge it with 14.4V and the correct polarity.  Since it was a lead-acid battery and not a gel one, I first assumed it was dried out.  Cracked open the top cover, removed the rubber plugs and fill each element with de-ionized water until the water was was about 3 mm above the plates.

After filling it with water I was expecting to take at least a few mA in normal charging mode, but nope.  Still nothing, so I connected the battery with reversed polarity (- of the battery to the + of the charger), with the power source set at 14.4V/180mA max.  The current indicated by the power supply was about 30mA at first, and in a few minutes reached the 180mA set limit

To my surprise, after a few minutes of reversed charging, the voltage started to jump/fluctuate (about a few times a second, or so, between jumps), also it was some very, very slow gassing (I left the rubber plugs opened), so I start
logging the voltage at each minute.

Strangely, the time between voltage jumps was random, but the voltage was about 1.2V or so.

Today I give it another try, this time using good wires instead of the very cheap Chinese banana/alligators wires from yesterday.  Now there are no more voltage jumps, and I'm curios if this is because the plates had time to soak over night, or because of the good wires.

TL;DR
Anybody remember seeing voltage variations jumping approx. 1.2V up and down during reverse charging?

[tautech]

If you are using CC PSU mode yes the voltage will drop as the battery starts accepting charge....reverse or forward charge.