I installed a battery monitor today, a PentaMetric unit from Bogart Engineering. I wanted to get a clear picture of our battery usage before I consider installing any solar panels.
PentaMetric Components - Bogart Engineering
I installed the battery shunt in a water proof outlet box from Home Depot on the side of our battery boxes -- the shunt can be mounted out of doors but it may deteriorate over time in the rain. There are five wires mounted to the shut: negative from the battery, negative to the frame, negative to the battery monitor, sense + and sense - on the top of the shunt.
The monitor comes with a temperature sensor, which I attached to one of the batteries negative pole (there is no electrical between the battery and the sensor, it was just a convenient place to mount it).
I ran the wire into a compartment that we opened up in front of our bunks -- this is a mod done by several X213 owners for storage but we'll use it for equipment like solar charges and inverters if we decide to proceed with the solar installation. I had to run a cat6 wire back through the underbelly to where I will attach the Ethernet interface. This is a real pain on units with a sealed underbelly like ours.
While I was at it I installed a battery disconnect switch, added a fused connection to power the monitor and cleaned up the parallel wiring of our batteries done by the dealer.
The input unit will be mounted in the front compartment where the wire enters, the Ethernet interface will be mounted behind the couch, and the display monitor will be mounted above our tank status display.
Hopefully this will give us a clear picture of our DC power usage over time.