12V battery maintenance for dummies when gone for weeks

I realize you are trying to be helpful but what explains 1 replacement battery in 10 years on my gen4 Prius using it in a rotation with my other 2 vehicles?

 

I know how the Gen 4/Gen 5 Prius BMS works, as I studied it with a battery monitor. You don't know the current SOC of your battery. At least, get a BM2 battery monitor and find out. I bet it is below 50%. Just because you have escaped so far from a dead battery doesn’t mean it will never happen.

Other battery maintainers might work. I hope what you have is a smart battery maintainer and not a dumb trickle charger as you think, since the latter can damage the battery.

 

I have 3 of those, lol. 1.25 amp model. I think they're good. They might be the original 'battery maintainer', not sure. Gotta be careful about throwing the term 'trickle charger' in these parts, lol.