But if it shuts off and stays off - what good is it?

Or does it turn back on from time to time?

See, I have never looked at them to determine what is available today. Mine supposedly "will not overcharge your battery" (as it said on the box), but come spring, half the fluid was gone. At the time, my experience with electronics and batteries was lacking.

I have almost 30 years behind me now, I don't have all the answers, but sure have more intelligent questions to ask.