House batteries not charging while driving

[Grampswrx]

Baja trip was perfect! Great waves and no people.

[sajohnson]

This solenoid with contacts rated 200A continuous duty works well:
Cole Hersee-Cole Hersee 12V 200A Continuous Duty Solenoid - 24213-24213-BK

I'm not necessarily recommending that vendor, but many people have gotten good service from that solenoid.

You might consider testing the existing solenoid first, although there's a good chance it's bad since the previous owner messed with it.

[Grampswrx]

Ended up going with the blue sea 7611 separator. was right in the budget and fit with the time constraints I had. Thanks to everyone for their input!