> I didn't mean to imply that
> if one battery was bad it would absolutely take out the second.

If you have two batteries in parallel and one fails, it will just
beat up the other one until it fails.  911s had two batteries in
the front fenders in the late 60s, early 70s, and it was the rule
never to replace just one "bad" battery, but to replace both.
I had a '72 911T for many years, so had lots of first hand
experience with this.  You could get by for a little while after
the first went bad, but you were on borrowed time....

Of course, "parallel" means that--no relays, no isolators, etc.

Richard
Boulder