Dean,
Frankly, on that long a run, you can use 'most any size you want. The
resistance of a smaller wire will limit the charge current, but since
you're probably not interested in fast charging. BUT, you'd better include
a low current self-resetting circuit breaker up front just in case the rear
battery is dead and you try to start the Onan. Now, if you want fast
charging, and the ability to start the Onan, you'd better use large
diameter wire, something like #2 or bigger. And in that case, you'd better
put a high current CB in it up front to protect everything from a short
along that long wire. In either case, you'll need a CB similar to the one
up front to protect the rear battery from shorts too. Check the Onan
starter current draw and a wire size/current chart to refine my WAG.
Ain't nuthin' simple!
Ken H.
On Wed, Feb 6, 2019 at 3:33 PM Dean Hanson
wrote:
> I plan to run a new wire from the isolator to the rear battery on a 75
> Avion
> coach. Anyone have a suggestion as to the wire size I need to use?
> Obviously
> to charge rear generator/house battery.
>
>