Personally, I have not found the need to provide for an isolator in my dual battery install.

I like to have a consistent draw on both batteries as I subscribe to the theory that consistent draw leads to longer battery life.

ON my motorhome, I do have battery isolators to disconnect the batteries so there is no parasitic draw when the MH sits for long periods of time.

The website you provided does have a quality isolator that is used in many applications and should work fine to split your two batteries.

John Stewart
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