[Milsurplus] Re: Lead-Acid batteries and Sulphation...

[jay_coward@agilent.com]

Very interesting!
Jay

-----Original Message-----
From: Kenneth G. Gordon [mailto:keng@moscow.com]
Sent: Wednesday, January 15, 2003 9:48 PM
To: milsurplus@mailman.qth.net
Subject: [Milsurplus] Re: Lead-Acid batteries and Sulphation...


John Watkins wrote:

>   Lead-Acid storage batteries, when stored discharged, go into a mostly 
>   irreversible state called sulfate sulphation.  so far, only very large 
>   stationary batteries (on the order of 500 to 1000 AH and larger) can be 
>   somewhat reversed from a sulfphation condition, but at great expense of 
>   electricity and time!   Smaller batteries such as truck & car batteries and
>   smaller are mostly irreversible, regardless of efforts taken.  Definitely gel
>   batteries are dead after sulphation.

In my experience, this is most assuredly true: however, 
SOMETIMES you can, at least temporarily, depending on the 
battery, rejuvenate a truck & car lead-acid battery. When I was 
much younger and poorer, I did it regularly when necessary.

Before I discuss my method, I must warn you that it is pretty 
dangerous and must be done outside only. There is a lot of 
hydrogen gas given off and there is danger that the battery can 
explode if any of the cells are shorted internally.

What I would do is first make sure the battery was add water to 
each cell that needed it. I would also test each cell individually to 
see whether or not they were all similar in voltage. I hoped that this 
would preclude any shorted cells. 

Then I would connect the battery to my Dad's DC arc welder with 
the weld current set as low as it would go.

Usually if the battery was badly sulphated, there would be no or 
very little current flow.

Then I would crank up the weld-current to somewhere above 
the180 amp marking on the dial and wait.

Eventually the battery would start to take current, and after a bit 
there would be a lot of gassing from the battery.

I would let the battery cook for a bit, then I cranked the weld-current 
control down to its stop, turned the welder off, and THEN 
disconnected the cables.

After the battery cooled, I would pour out all the old electrolyte and 
wash the battery out with distilled water.  I would get a lot of brown 
material out of most of them. At the time I assumed this was the 
sulphation from the plates.

Then I would fill it with new electrolyte and the battery would be 
useable for quite some time. Eventually, it would fail and I would 
do another one. Some batteries I resurrected by this method would 
last a year or more: some only lasted a few months.

YMMV...:-)

The most reliable storage batteries in my experience were the 
Nickle-Iron-Alkaline, or Edison, batteries. Some used in mine cars 
in Butte, Montana were nearly 100 years old and still useable.

Ken Gordon W7EKB
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