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Epsom salt in lead-acid battery
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Refrigerator:

--- Quote from: Rick Law on December 17, 2020, 05:29:41 am ---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.

--- End quote ---

Those 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.
G7PSK:
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.
coppercone2:
https://www.henkel-adhesives.com/at/en/product/structural-adhesives/loctite_aa_3038.html

this 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 finish

I wonder what equivalent of firework it would be equal to for testing
james_s:

--- Quote from: G7PSK on December 18, 2020, 03:50:31 pm ---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.

--- End quote ---

Yikes!  :o

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.
coppercone2:
for a lab battery its a good project to make a housing with fuse and terminals
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