That is the extent of my testing. But I wait longer, usually a few days or more, to get what I think is a true state of charge from the voltage.

I've done it long enough that I see a trend coming, usually a few months before failure. And it simply shows as he says, a battery that won't stay above 12.5-6 volts for a day or more, after a full charge. You can limp it along if you want(many do) but it simply has little capacity to store a charge,

Is there someplace that he addresses my question; charging vs not charging over the winter- will it extend my GRP27's life? I couldn't find it, Bruce. Thanks.