Are there any batteries do not deteriorate while stored?

wpns said:

Please don’t put HCL into dry lead-acid batteries. Not sure what will happen, but it won’t be what you expect, and will probably involve a hazmat team for the chlorine release.

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Note - this all refers to simple flooded lead acid batteries. AGM uses a gel paste type acid that can't be replenished by adding battery acid.

They sell the dry batteries for long term storage without degrading. They also sell the wet acid in a bag-n-box format for filling the battery. We used to always get batteries for tillers and other farm equipment dry and we had a box of acid on the shelf for such an occasion.

We also would take a battery that wouldn't hold a charge and empty the acid out and refill it. Most of the time that would get you another year or so, but left you with disposing of the acid. We poured it over tough weeds in places we never wanted anything to grow.

robbob2112 said:

We poured it over tough weeds in places we never wanted anything to grow.

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Wonder if that works for Japanese knotweed. Past the jokes though not sure the guy wants to empty battery acid out every time he leaves his camper.

ThaiTaffy said:

Wonder if that works for Japanese knotweed. Past the jokes though not sure the guy wants to empty battery acid out every time he leaves his camper.

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It might work, but with a deep tap root I wouldn't be sure of anything.

And, I wasn't suggesting he empty batteries to store - I think storage has been covered for the various battery chemistries.

I never really thought about companies selling dry batteries- makes total sense.

That's some good knowledge. If I had an end-of-the-world bugout cabin or something, wouldn't be a bad thing to have.

Makes me wonder on the shelf-stability of acids, though. How much would a sealed container in a cool, dry place degrade over 10 years, for example.

As far as the original topic goes, I would probably discharge mine to around 30-40% if they were going to sit totally disconnected and the BMS has some kind of physical disconnect or a storage mode. There's the obvious risk of having the batteries die from the BMS discharging them very slowly over the course of a year. Maybe less of an issue with a huge solar battery.

I can say on my power tool batteries, I discharge them down to 2 of 4 bars (couldn't tell you at all what that means for the SoC) and toss them in the drawer. The real problem is keeping track of trying to rotate through them when using them...

Dagoth Ur Does Solar said:

Makes me wonder on the shelf-stability of acids, though. How much would a sealed container in a cool, dry place degrade over 10 years, for example.

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Pretty much nothing, it's dilute H2SO4, what's going to happen to it? Google says essentially infinite, which is probably longer than your dry batteries. I get 'motorcycle' batteries for my generators every few years, and they look like they have a pretty good storage life (and are easy to activate).

wpns said:

Pretty much nothing, it's dilute H2SO4, what's going to happen to it? Google says essentially infinite, which is probably longer than your dry batteries. I get 'motorcycle' batteries for my generators every few years, and they look like they have a pretty good storage life (and are easy to activate).

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We used the same 2 gallon box of acid stored on a shelf in an unconditioned space in Ft Worth TX for around 20 years. When emptying the shop out 10 years later to move my mother I poured out the last quart and it still sizzled.