Battery heater and charging station. Batteries have a hard time charging when it's super cold out. A couple chargers and a 40 watt bulb in an old cooler should do the trick! :
1 of SNAP-ON CTC596 Battery Charger Input AC 120V Output 7.2v-9.6v New | eBay
Topdon Battery Charger 12/24v Car Auto Power Repair For Car/moto/tractor/suv/boat/truck/atv/mower Lead Acid Li Battery T4000 - Car Battery Tester & Charger Tools - AliExpress