I purchased a Xantrex TrueCharge 20+ for my boat. Since I only have two
batteries, I'm wondering about the advisabilty of using the third (unused)
charger output to run on-board 12 V 'stuff' while plugged into shore power.

What I visualize is a cable from the charger to a CB (CB1) switch, which then would
go to the primary DC breaker/disconnect (CB2)

charger ---CB1---CB2---DC Panel---Load
Batt---Bat SelSw-----^

Any pros/cons you see?

Regards,
Norm B