Went to get coffee and when I got back in the car there was no power. Hmmmmm.
Popped the hood and put a meter to the battery. 12.86v. Good enough. I noticed the battery from 2005 had leaked a bit onto the negative terminal. Cleaned both of the terminals, hooked back up and power is restored.
Glad I keep tool box in there. And I guess it’s time to replace that battery. I knew I should have done it awhile ago just because of the age, but these are massive batteries and a pain in the ass to get out.