Seriously, I never gave this too much thought. I have a smaller Stinger that I used for the last four years as my secondary battery (in line from primary to amps)
That Stinger seems to lose all it's juice intermittently, so it's time to replace. the question is, just how much better is (BRANDXYZ) 'car audio' batteries compared to the 'top shelf' marine deep cycle battery?
Aren't a lot of them just rebranded from (MANUFACTURERX)?
I know, amatuer Q (from an old guy that's been into good stuff for three decades...)