There are several variations on lead-acid, which is what I was going on about. Some batteries use calcium in the plate alloy and are "maintenance proof" - your car battery is that type. Those won't deep cycle for many times. Many batteries, to get a large peak output use many thin, instead of a few thicker plates - and they don't cycle for as many times either. The plates just fall apart and the paste falls out.
In fact, in my own system, I use a couple of "deep cycle" trolling batteries (from walmart) as a peak provider across my real "submarine" lead acids, and they only last about a year. When I did this with my L16 (golf cart batteries) I got 12 years out of them, vs the 6-7 most people get. Those wallmart batteries with only 100 ah or so actually have more plate area (lots of thin plates) than my big 500 ah deep cycle batteries do, and thus die in fewer cycles as the plates warp or fall apart.
In actual tests here, a truck type lead acid only lived through about 20 cycles before losing over half its capacity. While an L16...a few thousand. The Rolls-Surrettes I use now have a 20 year guarantee....all are "lead acid" generically speaking.
I once bought some surplus phone company batteries. They were NOT long lived in cycling.
BTW, my little honda is back in action. Sitting it next to the woodstove with the covers off overnight did the trick. And I got enough sun today such that even with only a few panels cleared off - I got full charge on the house. Tomorrow is supposed to be sunny too, and I might be able to "pay back" the Volt if I go out on the roof and move some more snow. I have a 4-6 foot deep pile in front of the panels in front of the house, which sadly, will be rock hard after tonight's hard freeze. All that junk has to go someplace.
