Trailer brake battery

[Moon Lake Refuge]

Hi all, looking to wire the fish house to take a charge from the truck while driving but was curious if I run power to the house battery AND the brake battery will it backfeed from one to the other when not hooked up to the truck?  If so did you just install a diode before the brake battery to prevent any current from traveling back?

Thanks,

[Lip_Ripper Guy]

I believe they will keep each other at the same voltage without some sort of switch(es) involved.  

[Moon Lake Refuge]

Stopped in at the RV shop last night and they did say that If I wired them both from the truck they would share voltage, and if I completely drained one it would drain the other as well.  He said one way diodes on each line would keep them separate or for safety I could just throw the diode on the trailer brake battery so that my house battery wont drain it but if my trailer brake battery dies or goes low it could back feed from my house battery.  I have a couple small batteries I may wire this and test it out with.