How long can a battery stay out of the car and be "ok"?

[JHZR2]

Decided to swap in a lighter H5 battery for my H6 AGM. I am tryign to sell it as it's only ~6mos old but if I can't, how long you just store a batter on the shelf? Does it need to be charged regularly?

Batteries do self-discharge. This is slower when cold, faster when hot. Cars add their own parasitic draw to the battery, no matter how small. It speeds up that discharge quite a bit…

So sitting alone it can stay charged quite some time. But I’d want to charge it fully first and then check it monthly…

 

[JHZR2]

I just bought a fuse box and a bunch of sae connectors so I can gang the “winter batteries” together on one maintainer during the off season. Kind of excited about the project. A noco genius will power it, and each leg is fused at the hub and at the battery.

Be careful with that. Parallel batteries with different capacities and states of health can be a recipe for disaster.

 

[sk_pete]

I swear by, not at, BatteryMinders. I get 10 yrs. out of my motorcycle and snowmobile batteries for example. And only have changed them due to age, not lack of cranking power. Always plugged in when in garage. The maintainers have paid for themselves many times over.
8 batteries currently plugged in.

likely you paid more in e-bill than saved.