Author Topic: Epsom salt in lead-acid battery  (Read 9043 times)

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Offline Rick LawTopic starter

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Epsom salt in lead-acid battery
« on: December 16, 2020, 04:18:32 pm »
Some web articles and youtube videos suggest reviving a lead-acid battery by adding a solution of Epsom salt in distilled water.  Some even suggest draining the old acid and refilling with Epsom salt in distilled water solution.

Web being what it is, anyone can claim to be an expert.  It doesn't seem right to me, but I am not an expert.  So, I turn to the expert here...

Anyone here ever tried that?  What are your results?

EDIT - corrected - Epsom salt, not Epson salt...
« Last Edit: December 16, 2020, 04:36:21 pm by Rick Law »
 

Offline BravoV

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Re: Epson salt in lead-acid battery
« Reply #1 on: December 16, 2020, 04:20:48 pm »
You mean Epsom right ? Not Epson.
« Last Edit: December 16, 2020, 04:23:09 pm by BravoV »
 
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Offline Rick LawTopic starter

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Re: Epsom salt in lead-acid battery
« Reply #2 on: December 16, 2020, 04:34:59 pm »
You mean Epsom right ? Not Epson.

You are right, I corrected the post!
 

Offline jogri

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Re: Epsom salt in lead-acid battery
« Reply #3 on: December 16, 2020, 04:50:52 pm »
Doesn't strike me as a valid tactic,

since when does the addition of a sulfate to a battery that already has a way too high sulfate concentration lower that concentration? If anything, it prevents lead sulfate from dissolving, making the problem worse. Give it a shot if you have nothing to lose (the battery is dead anyway), but don't get your hopes up.
 

Offline james_s

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Re: Epsom salt in lead-acid battery
« Reply #4 on: December 16, 2020, 06:36:34 pm »
I saw a youtube video a while back where a guy tried that on a few different old batteries and it didn't help.

The few times I've dissected a worn out lead acid battery it was obvious that there was no saving it. The plates weren't sheets of lead, they were more like sheets of corrosion that crumbled to bits.
 

Offline edpalmer42

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Re: Epsom salt in lead-acid battery
« Reply #5 on: December 16, 2020, 07:49:18 pm »
There are many ways that a lead-acid battery can fail.  Some are chemical, some are mechanical.  If the Epsom salts work at all, it will only be able to fix a chemical problem, not a mechanical one.

The biggest chemical failure I can think of is sulfation.  Lead Sulfate is hard and non-conductive.  Once it forms, it insulates active material under it.  I think this is the fault that Epsom salts is claimed to fix.  Sulfation also tends to cause the plate to grow larger which can cause mechanical damage to the cell.

Mechanical problems that I can think of off the top of my head are:

1.  Plate corrosion.  Vibration, gas generation under the surface of the plate - mostly while charging, and temperature cycling can cause material to be shed by the plate.  The shed particles fall down to the bottom of the cell and create a sludge.  If the sludge builds up high enough, it'll short out the cell.  The shedding process will also reduce the cell's capacity by reducing the amount of active material in the cell.  Eventually, the corrosion can get so bad that the cell just falls apart.  Batteries designed for high output amps, like car batteries, have to have thin plates to maximize the surface area exposed to the acid.  Thin plates make plate corrosion more of a problem.

2.  Freezing.  If the battery's state of charge is low, it can freeze.  The ice expands and wrecks everything.  If the battery is fully charged, the freezing point is so low that you probably don't have to worry about it.  Note that some batteries are designed with an acid concentration that is low enough that it will freeze.  These batteries are only intended for indoor operation.

3.  Obvious mechanical insults like dropping, hitting the battery, etc.  Lead is soft and heavy.  It will break, twist, shear, etc.

Because of all these potential problems a particular battery may or may not respond to an Epsom salt treatment - if the basic chemistry even makes sense.  There's also the question of what are the performance characteristics of a treated battery?  Cranking amps?  Capacity?  Freezing point?

I'd be worried about turning a dead battery into a weak battery that might let me down when I need it.

Ed

P.S.  Refilling a battery with Epson printer ink?  Hmmmm  :-//
« Last Edit: December 16, 2020, 07:56:52 pm by edpalmer42 »
 

Offline jogri

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Re: Epsom salt in lead-acid battery
« Reply #6 on: December 16, 2020, 08:45:03 pm »
Because of all these potential problems a particular battery may or may not respond to an Epsom salt treatment - if the basic chemistry even makes sense.

Problem is, it doesn't. You want to get rid of/dissolve the lead sulfate, so you obviously have so much lead sulfate that it won't stay in solution and falls out to make the crystals. By adding more sulfate even more lead sulfate will fall out of solution... You have to lower the sulfate concentration to dissolve it, not add more sulfate (in the form of Epsom salt, magnesium sulfate). The addition might have some secondary effects (lower resistance bc of saturated sulfate solution), but it won't fix the sulfation problem, it'll just make it worse.
 

Offline Refrigerator

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Re: Epsom salt in lead-acid battery
« Reply #7 on: December 16, 2020, 09:14:13 pm »
It will lower the internal resistance of a sulphated cell but will not restore the original capacity, only a little bit.
That's what i've found from my experiments.
I have a blog at http://brimmingideas.blogspot.com/ . Now less empty than ever before !
An expert of making MOSFETs explode.
 

Offline coppercone2

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Re: Epsom salt in lead-acid battery
« Reply #8 on: December 17, 2020, 01:28:14 am »
I think I got some life out of batteries that way before but I think if you add too much epsom you poison the cell, so its gambling
 

Offline Red Squirrel

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Re: Epsom salt in lead-acid battery
« Reply #9 on: December 17, 2020, 03:16:00 am »
From what I understand it will work but very temporarily.  I would not try it unless the battery is already shot anyway.
 

Offline coppercone2

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Re: Epsom salt in lead-acid battery
« Reply #10 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.

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).
« Last Edit: December 17, 2020, 03:57:54 am by coppercone2 »
 
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Offline Rick LawTopic starter

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Re: Epsom salt in lead-acid battery
« Reply #11 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.

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.
... ...

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.
« Last Edit: December 17, 2020, 05:36:26 am by Rick Law »
 

Offline coppercone2

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Re: Epsom salt in lead-acid battery
« Reply #12 on: December 17, 2020, 05:58:36 am »
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.
 

Offline edpalmer42

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Re: Epsom salt in lead-acid battery
« Reply #13 on: December 17, 2020, 06:02:58 am »
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!  :)
 

Offline james_s

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Re: Epsom salt in lead-acid battery
« Reply #14 on: December 17, 2020, 06:48:36 am »
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.
« Last Edit: December 18, 2020, 07:40:59 pm by james_s »
 

Offline Refrigerator

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Re: Epsom salt in lead-acid battery
« Reply #15 on: December 17, 2020, 12:49:39 pm »
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.

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.
... ...

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.

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.
I have a blog at http://brimmingideas.blogspot.com/ . Now less empty than ever before !
An expert of making MOSFETs explode.
 

Offline G7PSK

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Re: Epsom salt in lead-acid battery
« Reply #16 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.
 

Offline coppercone2

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Re: Epsom salt in lead-acid battery
« Reply #17 on: December 18, 2020, 07:31:38 pm »
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
« Last Edit: December 18, 2020, 07:33:32 pm by coppercone2 »
 

Offline james_s

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Re: Epsom salt in lead-acid battery
« Reply #18 on: December 18, 2020, 07:44:16 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.

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.
 

Offline coppercone2

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Re: Epsom salt in lead-acid battery
« Reply #19 on: December 18, 2020, 08:24:21 pm »
for a lab battery its a good project to make a housing with fuse and terminals
 

Offline tcsaba101

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Re: Epsom salt in lead-acid battery
« Reply #20 on: December 18, 2020, 09:53:40 pm »
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!  :)

I had some success in flooded lead acid batt rejuvenating in the last years. Not in other battery types.
I found some rules what may help some of you.

Anyway, the basics are written down almost 100 years ago: https://www.powerstream.com/1922/battery_1922_WITTE/battery_WITTE.htm#toc

Pulsers have to install on the battery in early stage, this is a prevention tech, not a cure  (but sometimes worked)! Preventing to build up sulphate layer on the lead surface.
I found this company's products the best: http://www.megapulse.de/.

The main problem is the low charging voltage, what in some cars 13.8V. The charging should go up to 15-16V of course at low current, that can solve the sulphates on the lead surface.
The installed pulser only works when the batt voltage is >13.5V, and makes 20-50V short pulses what is handling the sulphates effectively.
One of our forklift is working for 10+ years and the battery is still fine, of course it needs maintenance.
One pulser can handle the battery of two cars, forklifts, if you change on the batteries regularly.

About dead batteries as mentioned earlier in this blog, mechanical or chemical damage can be the issue.
When no mechanical damage, there is some hope to rejuvenate if the battery has had low cycles.

The lead acid battery lifetime is about 700 cycles average.

But if the cycle data is not clear, I have found some tech to find out whether a battery have some hope or not.

1. Inspect mechanical status and if you can check cell voltages do it, if no visible issue, next step.
2. Use a CV, CC power supply, and set CC= Capacity/100 current or less (in case of an 50Ah battery, CC<= 500mA), CV= 15.5V, and charge the battery.
3a. If it reaches the CV within a week, there is a hope, discharge to 11V and repeat the charge>discharge 2-3 times, that will handle the sulphate, and the battery may works for additional 1-2 years, the pulser will help.
3b. If never reaches the CV then you can try epsom salt, or other miracles....

As I experienced the 10% of batteries can be rejuvenated, the younger the battery, the chance is higher.

It is forbidden by law to make rejuvenating commercially in my country, but as a private I can do.





 

Offline Rick LawTopic starter

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Re: Epsom salt in lead-acid battery
« Reply #21 on: December 18, 2020, 11:11:48 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.

Wow!  I was expecting blow-ups to be merely large cracks with some spraying.  This one you got looks like it was worked over by explosives.

Do you have a suspect?    Since you said "this pulse charger is the worst one I have ever tried", is that your suspect?  Hydrogen build up perhaps?  Shorted?

I am thinking of experimenting with those low amp/frequency pulse desulfator (not charger).   Thus far, when I charge these old defunct batteries,  I have been careful about making sure that the battery is vented and the cover held down only by a rubber band so hydrogen pressure can escape fairly easily.

I've found a research paper on the web, they have good success pulsing high freqency at 140A.  I am hunting for that paper again since I did not note the source.

This is giving me a second thought.  Perhaps I should wait till spring time so I can do it in a bucket in the backyard, or find something else to be curious and to experiment with.
 

Offline james_s

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Re: Epsom salt in lead-acid battery
« Reply #22 on: December 19, 2020, 01:53:18 am »
That was a hydrogen explosion for sure. I don't know what set it off, maybe a broken connection sparked? I'm sure what happened though is electrolysis released a mix of hydrogen and oxygen which would be in perfect proportions and something ignited it causing an explosion.
 

Offline coppercone2

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Re: Epsom salt in lead-acid battery
« Reply #23 on: December 19, 2020, 02:07:53 am »
was that a SLA or a wet cell?

I think SLA is safer because the stuff inside of it dampens the explosion
 

Offline G7PSK

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Re: Epsom salt in lead-acid battery
« Reply #24 on: December 19, 2020, 09:15:04 am »
It was a wet cell, a deep cycle Yuasa brand which was never used as it was purchased about 15 years ago for a wind turbine project there was four originally but it was decided to go with some large single cell batteries of 2.5 volt each and 900 amp hour. Three were given away years ago and this one kept and put on charge about once a year this time around it would not take a charge so I purchased one of those pulse chargers. I would not be surprised if it was the pulse charger that popped first setting off the battery. The pulse charge was a Chines made switch mode affair so it is more that likely that a cap. exploded and acted as a detonator for the battery.
Last time I try to recover a smallish lead acid, big ones yes I can take them apart wash them out and scrape the plates if required.
 


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