Recently have added a 2nd battery in a second vented box, a pure sine wave inverter and a TS-30 automatic transfer switch to the 5th wheel.
Decided to go the automatic transfer switch route as opposed to a manual transfer switch as described in a previous post.
Manual Transfer Switch Installation
Looked at a number of websites but no one suggested a solution so the battery charger in the installed coach converter does not charge the battery when the inverter is supplying 120 VAC to the rig. Pondered for a bit and decided to install a solid state relay. The small relay mounts very well in the TS-30 automatic transfer switch case. The relay I picked is small, requires very little power.
Opto 22 120A25 AC Control Solid State Relay
See Opto 22 120A25 AC Control Solid State Relay, 120 VAC, 25 Amp, 4000 V Optical Isolation, 1/2 Cycle Maximum Turn-On/Off Time, 25 - 65 Hz Operating Frequency: Electronic Relays: Amazon.com: Industrial & Scientific
Mount the relay inside the TS-30 and connect the coil side of the relay to the shore power side. The relay will then be energized and a set of its contacts will be closed when on shore power. Run some ROMEX from the relay contacts to the installed converter. Find the circuit breaker that feeds the converter. Rewire so the load side of the circuit breaker runs to the new relay contact, with the other side of the relay contact feeding the converter.
The battery charger will then ONLY be enabled when shore power is present.
Then, of course, wire the TS-30 to the pure sine wave inverter, the MAIN circuit breaker and the original MAIN circuit breaker feed.