Yes, I always upgrade the alternator to starter cable to 6- or 4-gauge.
That's easier than running another cable all the way to the front since
the stock ('86-on) battery cable is already plenty large enough. When I
install an aux battery under the rear seat only then will I go direct to
the alternator.

On 7/7/2017 5:20 AM, Dennis Haynes wrote:
> I agree with Karl on many points here. I'll just add a few extra details.
> For the solenoid, there is really nothing wrong with alternator running based contactor operation. Many modern RV still operate the solenoid off the ignition switch. The relay used thug should be one more suitable for battery isolation charging operation.
> For the 6 gauge connection from the chassis battery to the house battery, a better choice is to go direct to the alternator. Otherwise at least upgrade the alternator harness to the starter post-chassis battery. This should be dome regardless especially if high wattage headlights are used.
>
> Dennis