I decided to leave my batteries on the boat this winter. Soon after putting the boat up on the hard, the batteries were both at about 12.6 - 12.7 volts. I charged both of them. Now after sitting for a few weeks, I read about 13.5 volts in both. Is this normal? They are clean and dry, with the cables removed. My volt meter was also left on the boat. Would it get wacky at 35 F?
Batteries really make me feel dim.