exactly when im lookin for. can that be mounted under the hood and spliced into the same plug as the block heater?

I didn't splice. I moved my block heater cord close to the charger, and used a 3 way extension cord.

napa's automatic trickle chargers are actually designed for this. I've always wanted to try it. I think it'd be a DOPE setup.

I really liked it, especially at work where it's always on. At home it only came on for 2 or 3 hours before I fired up in the morning. Still, enough time top them up for a powerful start.

be careful with trickle chargers that heat up the battery while charging. This so called ripple voltage indicates a bad (cheapo)charger and kills the battery. Choose the charger according to the battery(acid, AGM, gel) because these batteries need different charge voltages that they can handle safely.

A good charger switches over to float charge when the battery is full. Constant charge kills also your battery.:c: