BATTERY WIRING

I need some technical assistance in wiring JEZEBEL. I'm going to be running 4/0 cable from my big alternator to my house battery bank. I'm using this large cable because the run is about 35' one way and I want to limit the voltage drop. Will it work to tap off the 4/0 cable about 6' from the alternator to supply 70 amp power to the d.c. panel in the pilot house? Or, must I run another set of large cables from the battery bank back to the pilot house panel?

 

Thanks for any advice,

 

Don