Charging small sla batteries.

[sipi]

Is there any way of charging small sealed lead acid batteries from dead? The type used in mobility scooters and electric go-karts and that type of thing.

There is a lot of stuff if you goggle it but I have never been able to get it to work (Emptying them and using fresh acid etc). They are expensive and I have managed to totally flatten quite a few by just not using them. They seem to flatten themselves totally and then just refuse to charge again.

[Wirejerker]

Battery chargers need some voltage in the battery to trigger them to start. Try paralleling a flat battery with a battery that still has some charge in it and putting them both on charge. The charger should trigger around 10 volts.


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[sipi]

39 minutes ago, Wirejerker said:

Battery chargers need some voltage in the battery to trigger them to start. Try paralleling a flat battery with a battery that still has some charge in it and putting them both on charge. The charger should trigger around 10 volts.


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Ok will give that a go. I did manage to get one to start charging  (can't remember how) and after a while it showed fully charged, but as soon as I took it off the charger it had no power.

This stuff is way beyond my league so I really appreciate your suggestion, and others

[RichCor]

Battery Basics -- How Do Lead Acid Batteries Work?

Progressive Dynamics service department

 

...In figure # 5 the battery is now fully discharged, the plates are almost completely covered with lead sulfate (sulfation) and voltage has dropped to 10.5-volts.

 

NOTE: Discharging a lead acid battery below 10.5 volts will severely damage it!

 

Lead sulfate (sulfation) now coats most of the battery plates. Lead sulfate is a soft material, which can is reconverted back into lead and sulfuric acid, provided the discharged battery is immediately connected to a battery charger. If a lead acid battery is not immediately recharged, the lead sulfate will begin to form hard crystals, which can not be reconverted by a standard fixed voltage (13.6 volts) battery converter/charger.

 

 

How to Revive or De-Sulphate a Lead Acid Battery

patch.com - by Kamal (Patch Poster) - June 21, 2013

 

 

...and:

 

 

 

[impulse]

Look up "battery desulfator".

 

But keep in mind that it's hit or miss on whether they can recover a really bad battery, and how long it may take.

 

I bought a few different styles online from AliExpress.  I can't tell you whether they work because one of the batteries was too far gone and the other only needed a little "tune up" so I'd hate the give the desulfator credit...

 

And as wirejerker said, I had to parallel a decent battery to get the charger to even start.  A 12V power adapter from a long dead network router also worked to trick the charger into starting.

Edited May 19, 2017 by impulse

[sipi]

Annoying thing is that these batteries are practically brand new and not been used. Just gone dead and can't be resurrected. 

I will try the desulphur and parallel charge thing tomorrow. 

Thanks.

 

Edit. One was in one of those car battery pack things that I charged new then never used. It was actually not much more expensive to throw it and buy a whole new one than to just buy a replacement battery. 

The other four are in electric 24v scooters and motorbikes my son rides occasionally. They seem to die if shelved for more than a week or two.

Plus one in a computer ups, also practically brand new.

Edited May 19, 2017 by sipi

[impulse]

2 hours ago, sipi said:

The other four are in electric 24v scooters and motorbikes my son rides occasionally. They seem to die if shelved for more than a week or two.

Plus one in a computer ups, also practically brand new.

 

I always unplug the battery packs from my e-bikes if I'm not going to use them for a week or more (like the ones I use in China for just a few weeks every 3-4 months when I visit).  I also put a detachable ground terminal on my pickup battery after I screwed up a brand new battery with a few months of sitting in the parking lot when I had surgery.  The guy that owned the truck before me put in some kind of alarm system that seemed to leak just a little bit of amperage.

[sipi]

Yeah they are too expensive to have to replace all the time simply from not using them. I have gone through 8 of various sizes in the last 12 months or so.

I guess if and when I get this lot recharged (or replace them) I need to figure out how to keep them charged.

Maybe line them all up in parallel like toy soldiers with a trickle charge. 

I actually cooked one from over charging it. Seems a bit of a balancing act.

[sipi]

I tried the parallel charging with a good battery trick. Then jump starting it with another battery. I think my guinea pig battery is too far gone. Tomorrow I will try the distilled water method. Not looking good so far.

[Gary A]

A battery that shows 0 percent charge is normally toast. Even  what seems to be a dead battery will still have 9 or 10 volts in it. If at all possible, you should not discharge a battery below 50 percent. That would be about 12,1 volts. My solar system batteries are nearly 4 years old and I am very careful to keep an eye on the voltage. Discharging a lead acid battery too far will drastically shorten the life. Vehicle batteries run totally dead by leaving lights on or something like that may take a charge but you can bet that their life has been shortened considerably.

[sipi]

Ok thanks.  These things seem to discharge on the shelf from new.

I will avoid anything relying on sla batteries like the plague from now on.

Lesson learnt.

 

Edit..

A 5 ltr V8 mobility scooter might scare the crap out of shoppers at Tesco, but it sure beats relying on bleeding batteries.

I will start designing one right now.

Edited May 20, 2017 by sipi

[sipi]

Has anyone tried Epson salts?

Might be worth a shot before I replace another 4 batteries. 

Nothing to lose.

 

[sipi]

Ok I am not giving up without a fight.

Today I have one battery soaking in bicarb. It started bubbling heavily but has died off somewhat.

Other batteries have been refilled with distilled water or an epson salt solution and charged at various voltages and currents.

And my success rate so far has been....

Zero.

Anyway, tomorrow is another day.

[sipi]

Well that has been interesting. 

The one I filled up with distilled water and charged the hell out of is showing the most promise. 

Will continue..

[Crossy]

Personally I think you're on a hiding to nothing, I've had zero success reviving SLAs that have gone into deep-discharge, they are scrap

 

When you bite the bullet and replace them, also get one of the solar trickle chargers and hook them all up to it, just to keep them from self-discharging.

 

[sipi]

20 minutes ago, Crossy said:

Personally I think you're on a hiding to nothing, I've had zero success reviving SLAs that have gone into deep-discharge, they are scrap

 

When you bite the bullet and replace them, also get one of the solar trickle chargers and hook them all up to it, just to keep them from self-discharging.

 

It seams we are heading in the same direction. 

I have basically proven the epson salts thing to be all smoke and mirrors, "smoke" literally.

However..

The 12 volt battery that was holding no charge  (ie zero) and the plates were, upon inspection, heavily sulfurizationodized (?).. after filling with pure distilled water and literally charged to oblivion is now holding 14.2 volts according to my meter.

Not even sure if that is physically possible.

I think this is the avenue to continue experimenting along.

Nothing to lose..

[sipi]

1 hour ago, Crossy said:

Personally I think you're on a hiding to nothing, I've had zero success reviving SLAs that have gone into deep-discharge, they are scrap

 

When you bite the bullet and replace them, also get one of the solar trickle chargers and hook them all up to it, just to keep them from self-discharging.

 

Yeah that is plan B. How to avoid this situation in the first pace.