Charger for 12v (4 cell) TS LiFePO4 pack??

I'm wondering if there is a good charger solution in the 20-50A range to charge a 4 cell pack of Thundersky 100ah batteries? Must be automatic, set and forget, come back and it's charged. Most chargers that I've found are 24v and higher, something in the $100-300 range would be good. (This would be for charging the battery pack before being deployed on an oil rig monitoring system as backup power) yes I know, a bit ironic EV batteries on an oil rig.