Solar "generator" to charge batteries while in stored in a cave

[englewoodfl]

We're going to store our 2023 23FBT with disconnected AGM batteries in a cave that doesn't have any available 110VAC outlets. It's far to dim at about 10 LUX to use any solar panel. My thought is to get a smallish quality solar generator that I can take to the cave, start a charger (trickle?) and then return the next day or so.


Thoughts on the idea? Recommended brand/model? I want to stay with a know quality product just to reduce the probability of failure or fire.

[jeffmc306]

englewoodfl, if you charge your AGM’s to 100% then disconnect you’ll be fine - they won’t self discharge much unless you’re planning on leaving them for over 6 months.

We I say disconnect, I’m not talking about the switch by the door. You need to physically disconnect either with a master switch or removing the battery cables.

The photo below shows the Blue Sea disconnect I installed with our AGM’s before upgrading to a Victron MultiPlus II and Battle Born GC3.

[englewoodfl]

I'm going to do a physical disconnect at the negative side of the battery. The caves stay about 60F so guess I'll disconnect and not worry.
Thanks...

[PaulBristol]

I agree with JeffMC. 100% state of charge followed by disconnect.

Fully charge. This means charging for 14 to 18 hours or more. This insures all lead sulfate is removed from the plates.

Disconnect.

Monitor battery terminal voltage periodically. Fully recharge before voltage drops below 12.4 volts. This prevents accumulation of lead sulfate on the plates. Check voltage more frequently first. Less frequent as you become confidant how long yours will last.

You may find your rig will last 6 months. It may last 12 months depending on the condition of the batteries.

[uncle_bob]

As noted above, with AGM's in good condition simply disconnecting and letting them sit should be fine. The gotcha is AGM's that aren't in good shape. They can indeed self discharge.

The answer is for that is to replace the bad batteries. They loose capacity as they wear out as well as discharging faster.

Bob

[JeffKim]

Litterally a cave? Aren't caves pretty moist? I'd be a little worried about mold if it's an extended period. That and maybe bats and then there was that cave monster in Star Wars....hummm

[uncle_bob]

Originally Posted by JeffKim

Litterally a cave? Aren't caves pretty moist? I'd be a little worried about mold if it's an extended period. That and maybe bats and then there was that cave monster in Star Wars....hummm

Hi

One of the options when we lived in Kansas was storage in a (man made) cave. We never went that way but folks did. They sat above the water table so no big deal with moisture. Also no issues with tornados or hail damage . The same facility was also used for things like storage of records (back when things got written on paper .... ).

Bob

[SuperTrouper]

Cave case in point. https://www.archives.gov/publication...rian-frcs.html