You can get 12v 6ah lithiums from Amazon for under $25. They claim to have built in overcharge protection. I have been using them this summer in a backpack sprayer without issue.

TLew, just curious if you found any good resources that discuss solar panels and charge controllers for the smaller 12v lithiums and if a charge controller is really needed? I have not found much on the issue myself. Thanks

The only bad thing on these small lithium batteries is using below 32 degrees if you find one with cold weather cut off your feeder won’t work if it doesn’t have cold weather cutoff using below 32 will kill the output of the battery

It's ok to use them below 32 degrees - you just don't want to CHARGE them below 32 degrees.
I'm not aware of any that completely 'turn off' below 32 degrees.

It's easy to 'disengage solar charging' for low temps:
I used a cheap 5°C N.O. bimetal switch (in my wifi relay) to open the solar circuit (not charge) below 5°C (41F ) - like this one...https://www.ebay.com/itm/314706486001[/quote]

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There’s a lot of lithium batteries that have high & low temperature shutdown built in the bms . If you put a solar panel on one with no low temperature cutoff then your going to be charging it below 32 degrees. Shutdown on most lithium batteries below 32 degrees and above 140 degrees some have built in heater so the battery never gets below 32 degrees.

I ordered these.
https://www.amazon.com/dp/B09MD8R4M6?ref=ppx_yo2ov_dt_b_product_details&th=1

I didn't know about the 32 degree charging thing. So I just ordered a few of the temp cutoff thingys noted above. I guess I just wire it in on the positive wire coming from the solar panel to the battery?

^ yep, and tape it against the battery so it goes by the battery temp.

When I buy new SLAs for my feeder, I usually put them on a 12v mA battery tender to top off before I throw them in the feeder- you never now how long they've been sitting on the shelf. Is that ok to use on the lithiums or is there a better low amp charger option?