Originally Posted by NfiniteMile
What About Connecting The Heater Wire To 12 Gauge Stranded Along With An In-line Fuse Straight To The Batteries?
You can do this... The inline fuse should be as close to the battery bank as practical.
If your battery bank connects negative to chassis, you can run just the positive wire. In that case, connect negative from the heater to the chassis somewhere up front.
I ran subpanels in my build because there was no telling what else I'd like to power at the time. Its a futureproofing measure- if you know you're never going to need DC power anything else near the heater, just run the 12 gauge. I'm kinda glad I did.