12V 60A car battery , maybe dead?

[SeaMonkey]

Hello Seamonkey,

Thanks for the info. But i will like to ask why you added magnesium sulphate solution.  will only distill water not do?

Yes, distilled water is all that is needed.

I've been evaluating the use of Magnesium Sulfate as a
battery additive for a couple of years now.  I add it to all
of my automobile batteries when topping off the water
level in the cells and now add it to my sealed batteries
when they're in need of rejuvenation and water.

The Magnesium Sulfate raises the level of sulfate ion
in solution in the electrolyte which helps to keep the
lead sulfate which forms on the plates insoluble and
therefore it stays on the plates instead of going into
solution.  It also increases slightly the conductivity of
the electrolyte to assist charging and rejuvenation.

I prepare a saturated solution of Magnesium Sulfate
with distilled water and add it to the batteries as
necessary.

The two 12 Volt 8 Ampere Hour batteries that I've been
most recently rejuvenating were removed from a scooter
where they'd been sitting unused for at least two years.
So far they're now showing near normal charging voltage
and are able to power a load for several hours at a low
rate of discharge.  Their internal resistance is still too
great for powering any loads at a high current level
so this probably means that there is still considerable
sulfation in the plates.  When I first began battery
rejuvenation about 12 years ago certain heavily sulfated
batteries took more than two months of continuous
pulsing to restore maximum capacity.  The circuit I used
back then was very low power.

[SeaMonkey]

The one thing to watch out for is if too much lead has fallen from the plates and built-up at the bottom of any of the cells, then it can short out that cell.  At a convenient point between cycles you might tip the battery up at a low angle: say 5 to 10 degrees and let it set and check the terminal voltage from time to time.  If it drops by about one cell's worth, then the desulfation will only help for a short time as you are on the verge of permanent battery death.

Yes, I've experienced those unexpectedly occurring "shorts" in
the cells when working with several old automotive batteries.
Just as it looks like its about to begin recovery one or more of
the cells suddenly develop "shorts."  Once they've reached that
degree of deterioration all they're good for is "cores'" when
exchanging them for batteries in better health.

[SeaMonkey]

One of the sealed 12 Volt 8 Ampere Hour batteries
seems to have developed a problem in one cell.

The battery can be charged to 14.4 Volts but when
left to sit for several days the battery voltage drops
to 10.8 Volts.  One cell apparently has some resistance
between the plates which is self-discharging the cell
rather rapidly.

These problems never seem to clear with sealed batteries.

I'll continue pulsing it for several more days to see what
happens.  Perhaps I'll perform surgery on it to examine the
bad cell and discover precisely what has happened.

Then, maybe not.

The other battery is responding normally thus far.

[Paul-R]

I had hoped that this thread was about replacing lead acid batteries with capacitors.

Is anyone working on creating a capacitor of capacity comparable to a 12V 60a BATTY?

[free4every1]

@groundloop
i noticed rodelu made a coil with twisted wire .
i don't see you mention twisting the wire in your first posting of the battery charger.
Is it really necessary to do this ?