I have a battery set up consisting of 4 group 24's divided into a
house bank of 3 and a starting bank of 1, controlled by a 3 position,
make before break, switch. The shore power charger is a Xantrex
trucharge smart charger.

The start battery has been running dry, while the house bank is
normal. It turns out that the reefer, while switched at the breaker,
draws from both banks simultaneously, and cannot be isolated to one
bank or the other.

My gut instinct is to sever the common connection. I believe that the
the draw down of the starter battery is a greater percentage of its
capacity than the house bank and thus the charger is frying the start
battery.

My question: Is there any reson for the reefer to be connected in
common to both batteries? What is common practice?