Costco GC2 spec
I decided to replace the old GC2 batteries (4 years old). Costco's GC2's are now labeled Interstate Batteries. There isn't much data on the battery, just RC = 107. A "real" Interstate battery that ...
Forum Discussion
pianotuna wrote:
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Definition of full is 1/2 amp charge rate per 100 amp-hours of battery bank. Or 1.28 specific gravity after resting for 24 hours using a temperature compensated SG measuring device.
As the jars charge they "push back" and amperage going into the bank drops. At 85% state of charge, acceptance rate is 12.5 amps per 100 amp-hours of battery bank. Raising voltage will increase gassing with essentially no net improvement of acceptance rate (exception--low temperature charging).
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Hmmmm, currently my mppt solar charger starts absorb at 14.8V (temp compensated) and stops at 1% of the ~420Ah US Battery GC2 bank (sun permitting). Then it floats. Maybe should drop that to 0.5% to be sure of a daily full charge ?
Could also increase the absorb V some as well to emulate top charging (? maybe up to 15V?). At the current 14.8V I only have to fill the batts every year or so (think the temp compensation helps a lot there), so that shouldn't be much of a problem.
This battery bank rarely sees shorepower and never sees generator charging. Just a daily solar charge cycle and the occasional manual equalization at 15.9V when I've got good sun.
