You guys that have a lithium battery in your locators, do you have a lithium charger??
Ice Fishing
Lithium battery charger
The lithiums I run for my trolling motor and sonar/electronics have Battery Management Systems (BMS) built into the battery. Leaving a traditional 12v charger too long on these batteries could cause faults to the BMS and could cause fire. The batteries also will not get a full charge.
I still use the same 12v charger, a cheap 500mA wall wart. Works just fine.
Most of the 12v lithium reach full charge at 14v or a bit more, which is very comparable to the old 7AH sealed lead acid batteries spec as well.
I recommend monitoring the charge with a voltmeter, then you know when it has reached the correct level and you can unplug. I printed out the battery spec and taped it to the side of my batteries for easy reference.
There does not appear to be any good reason to leave the charger on indefinitely, as very high state of charge tends to detract from lithium life. Also, they hold their charge way better than the SLAs did, so no good reason to leave them connected.
I do for my drills. If you are asking about rechargers for lithium AA batteries, I dont think there are any. I see lithium AA batteries all over, but I dont think any are rechargable. I wish they would make rechargable AA lithiums but I never saw them. They would surly put the other AA batteries to shame.