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Epsom salt in lead-acid battery
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tcsaba101:

--- Quote from: edpalmer42 on December 17, 2020, 06:02:58 am ---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!  :)

--- End quote ---

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.





Rick Law:

--- 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 ---

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.
james_s:
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.
coppercone2:
was that a SLA or a wet cell?

I think SLA is safer because the stuff inside of it dampens the explosion
G7PSK:
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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