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Discussion Starter #1
This message is again about the Group 31 Optimas that
were cycled a few times and then let sit for about 3
years.

I took the advice of the list and setup the slow
equalization charge at about 1 A. Note: these are
nominal 75 AH batteries.

After 88 hours the voltage across the battery
terminals has finally reached an even 13.0 V. The
battery itself, if the power supply is shutoff, will
still very quickly go to 11.8 V or so. So, it doesn't
seem to have taken any charge. The capacity is still
zero (i.e. resting voltage = 11.8, SOC = 0, resting
voltage = 12.8, SOC = 100%).

What should I do now? Continue another 24 hours?
Continue another 75 AH * 1A (charge rate) 75 hours?
I don't think the voltage is ever going to reach the
20 V or so that Lee mentioned (unless there is a major
spike after 13.5).

I'm surprised that after 88 hours, it is still only 13
V (considering it is a 75 AH battery).

I'm going to leace it on until at least 8:00 tonight
(making it a full 4 day charge). After that, I'm not
sure. I think I may be wasting my time and electrical
energy sinmce it doesn't seem to be taking a charge at
all.

I'm not sure what to do with them now. Thoughts?

Thanks,

Steve

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Discussion Starter #2
Steve Powers wrote:
> I setup the slow equalization charge at about 1 A...
> After 88 hours the voltage across the battery
> terminals has finally reached an even 13.0 V. The
> battery itself, if the power supply is shutoff, will
> still very quickly go to 11.8 V or so. So, it doesn't
> seem to have taken any charge...
> What should I do now? Continue another 24 hours?
> Continue another 75 AH * 1A (charge rate) 75 hours?
> I don't think the voltage is ever going to reach the
> 20 V or so that Lee mentioned (unless there is a major
> spike after 13.5).

If there are no bad or reversed cells, and the battery is just dead (at
0% state of charge), then as soon as you connected your 1-amp power
supply, the voltage should have immediately went up over 13v. Often, an
AGM or gel in this condition will immediately go past 15v! It won't even
draw 1 amp.

If the voltage while charging at 1 amp stays below 13v, even when left
on for days, then there is something seriously wrong with this battery.
Probably one or more shorted or reversed cells. It's not just dead; it's
damaged. Give up on it.

--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

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Discussion Starter #3
John Olsen at Optima published a white paper on resurrecting Optima
batteries. As I recall he said that spiral wound batteries don't self
destruct when over-charged (that is lead doesn't fall off of the plates. I
have brought several dozen back to life. Set the charge at 4 amps and allow
the voltage to go as high as 20 volts. It takes about 18 hours to reform the
plates. If you charge at less than 4 amps it doesn't work as well. If you
charge at more than 4 amps they overheat. But this almost always works.
(Norman Smith)

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