Renogy 20A dc to DC report

theoldwizard1 wrote:
If you are towing or using a truck camper, the B+ wire on the 7 pin trailer harness is almost always wired to a KEY-ON circuit. Now additional wiring required.

Yes, B+ on the 7-pin is a possible option. Several downsides to using a simple ignition on approach, however. The dc to dc charger would still continue to operate if the ignition is left on without the engine running--potentially depleting the battery. Plus, it would also continue to operate if the alternator fails. Having a very high amperage drain on your battery if your alternator fails, in the middle of nowhere, would not be fun.

We much prefer using a Battery Isolator with a 13.3v close/on, and 12.8v release/off relay. The BI prevents the dc to dc charger from operating unless the alternator is operating. If you turn on the ignition without the engine (alternator) running you're protected. If the alternator fails while you're driving, you're also protected.

The BI can be installed pretty much anywhere. Next to the dc to dc charger or on the TV. One option, wire the BI inline with the power cable feeding the dc to dc charger. Another option, mount the BI next to the charger and parallel off the input terminal of the dc to dc charger with a small wire and use the BI to simply open/close voltage to the Renogy's ignition trigger wire. We prefer the latter. One less connection/terminal on the primary power cable is a good thing.