mikieboyblue — There is an icon for the 12-V battery's state of charge in the dash display. It comes on when you put the car in ON (not READY) mode. You can trickle charge the 12-V battery as long as you keep the current low — the Owner's Manual says under 5 amperes. You cannot charge the high-voltage NiMH battery, and you shouldn't even try. (There are no accessible terminals that would let you do this anyway. The fused orange plug in the trunk is for disabling the battery. Its contacts cannot be used to charge it. First, the fuse is ~halfway along the series string of cells that make up the NiMH battery; and second, the battery floats relative to the chassis for safety. You don't have access to the actual battery terminals.) It would be very dangerous to attempt this.

Stan