Most batteries do not survive even going below 12.0VDC (50% charge state) for a long period of time.
I'm working on car start battery now trying to get it to hold a charge. It charges right up to 12.6-7VDC but when I hook it back up it starts slowly dropping Dc Voltage. It was reading around 2-3 vOLTS when I found it dead over the winter months... Car didn't get used at all over the winter months.
I'm hopeful it will return but probably only a pipe dream.
On the other hand my POPUP trailer deep cycle batteries were left sitting on the trailer tongue completely switched out of the circuit and they were all reading around 12.6VDC when I measured than a couple weeks back. They survived just fine and had normal fluid levels.. I normally leave them connected to my smart mode charger but this year I had the whole trailer shut down so just switched the batteries OFF-LINE over the winter months.
The trailer parasitic drains will drain me down to 12.0VDC is just a couple of weeks if I don't have my converter hooked up to shore power when setting in CAMP BACKYARD...
Roy Ken
