JKU 2009- Need 12volts Hot- but only when Engine battery is charged.

[Doghouse]

I'm installing a relay for Charging RV battery (DC to DC charger).
GOAL is to Charge RV Battery while minimizing risk of Dead JKu Battery.
Relay operation requires >10.4Volts and consumes 0.2 Amps to operate.
So, would like to Close the relay Only When Battery has Sufficient Charge.
Need to tap a wire under the hood that will be "12Volts On" But, only when battery is sufficiently charged.
Ideally, this would be a source near the battery or engine fuse box.
Welcome any suggestions.
Sincerely,
Doghouse

 

[JeepJeezy]

Are you looking to charge while driving or charge while docking?

 

[Danarch]

Not sure if this will work. I have one installed on my JK for the the GMRS radio. It will turn off power either based on a timer or when it detects low voltage in the battery. It has worked well for me so far.

https://powerwerx.com/automotive-dc-timer-lvd-battery-guard