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Epsom salt in lead-acid battery

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coppercone2:
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).

Rick Law:
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 am ---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.
... ...

--- End quote ---

So 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.

coppercone2:
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.

edpalmer42:
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!  :)

james_s:
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.

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