On my F I had wiring loom problems along the L/H inner mudguard/ wing/ fender/ whatever you call it where you are.
It was a short circuit in the loom, maybe that’s what killed your battery.
I cut the tape away from the loom, replaced the damaged sections of wire and retaped it…been fine since.
"Keep calm, relax, focus on the problem & PULL THE BLOODY TRIGGER"