Very Low OCV on Full Batts???
I've been seeing lower than usual resting ocv this winter, compared to last. Figured it was either wear and tear, too high a charging voltage, or a parasitic draw. So I tried throwing a lower vol...
Forum Discussion
There appears to be a suitable (t.c.) voltage that results in both high SG's and high resting ocv. This is, of course, battery specific. What works for my four 6's will obviously not work for a size 31 12v, for instance. What I'm about to say applies to what I have observed with my particular 6v GC-2's, and may or may not apply to a different battery type.
I believe Mex alluded to this "ideal" voltage in his 'antimony poisoning of neg plates thread', when he said;
"What I mean is progressive excess float voltage does a lot of damage. What is "excessive"? A certain voltage will render electrolyte a full specific density. A very specific amount of current will maintain that density. Anything less, the specific gravity slumps. Anything more, antimony starts packing its bags.
Note the crucial intention of the word PROGRESSIVE. Excessive charging voltages held for inordinately long periods of time will also cause antimony to take a hike." (end)
My batteries were over charged on several occasions last season, as the PEAK 40's voltage became higher as the season went on. Did this result in negative plate poisoning? I don't know. Are there times my bank appears to exhibit signs of heavy sulfation? Yes, but then taking into consideration temps, charging voltages, etc. reveals it is simply a matter of interpreting things in their proper, full context.
My conclusions at this point are, two things can result in lower resting ocv... too high a top charge voltage, on warm batts, and too low a top or float voltage, on cold batts . (I do not know the effects of too low a float voltage on warm batts, as I do not float my batts). At the same time, a lower top charge voltage on warm batts can result in higher resting ocv, and yet result in lower SG readings. So there is sweet spot, it seems, where both SG's and ocv have good results, and voltage is not so high that it causes antimony poisoning. Very cold / ever changing temps obviously make finding this sweet spot rather elusive.
But one thing is clear, de-stratification charging 'full', or very near full COLD batts, at too low a voltage, results in much lower resting ocv, and perhaps slightly lower SG's. So my question is, does this also ring true for warm batts? And if so, what is the effect, if any, of charging, to full, with a converter that drops to 13.6v, long before the batts are even near full? Do either the SG's or resting ocv's do well with this type of charging? And how would even warmer temps effect the results, even if that 13.6v was temp compensated? (I now know how cold temps would effect things). Likewise, how does 4 stage charging, i.e; the occasional 'de-stratification' charge, by said converter, at say 14.4v, effect SG's and resting ocv?
I believe Mex alluded to this "ideal" voltage in his 'antimony poisoning of neg plates thread', when he said;
"What I mean is progressive excess float voltage does a lot of damage. What is "excessive"? A certain voltage will render electrolyte a full specific density. A very specific amount of current will maintain that density. Anything less, the specific gravity slumps. Anything more, antimony starts packing its bags.
Note the crucial intention of the word PROGRESSIVE. Excessive charging voltages held for inordinately long periods of time will also cause antimony to take a hike." (end)
My batteries were over charged on several occasions last season, as the PEAK 40's voltage became higher as the season went on. Did this result in negative plate poisoning? I don't know. Are there times my bank appears to exhibit signs of heavy sulfation? Yes, but then taking into consideration temps, charging voltages, etc. reveals it is simply a matter of interpreting things in their proper, full context.
My conclusions at this point are, two things can result in lower resting ocv... too high a top charge voltage, on warm batts, and too low a top or float voltage, on cold batts . (I do not know the effects of too low a float voltage on warm batts, as I do not float my batts). At the same time, a lower top charge voltage on warm batts can result in higher resting ocv, and yet result in lower SG readings. So there is sweet spot, it seems, where both SG's and ocv have good results, and voltage is not so high that it causes antimony poisoning. Very cold / ever changing temps obviously make finding this sweet spot rather elusive.
But one thing is clear, de-stratification charging 'full', or very near full COLD batts, at too low a voltage, results in much lower resting ocv, and perhaps slightly lower SG's. So my question is, does this also ring true for warm batts? And if so, what is the effect, if any, of charging, to full, with a converter that drops to 13.6v, long before the batts are even near full? Do either the SG's or resting ocv's do well with this type of charging? And how would even warmer temps effect the results, even if that 13.6v was temp compensated? (I now know how cold temps would effect things). Likewise, how does 4 stage charging, i.e; the occasional 'de-stratification' charge, by said converter, at say 14.4v, effect SG's and resting ocv?
