I think Capt. Diehard is actually capt. Blowhard.

Batteries on concrete? I never figured out that silly rumor except
I've always heard people say to never set a battery on concrete because
it will kill it. or people would say, "That battery was good until I
set it on concrete".....

well.....

I''ve never seen very many batteries on the floor of anything what was
usually good very long. Chances are the battery was about half shot
but was still starting the car, then it gets set down in the garage
floor and neglected for 3-4-6 months, then somebody tries to use it,
and it's....dead.

"See, I TOLD you that putting that battery on a concrete floor would
kill it!"

uh-huh