Review on 🥶 TITAN RV Refrigerator Fan - Boost Fridge Vent Efficiency & Exhaust with Ultra High Volume Airflow, Mini Design, On/Off Switch, Smart Battery Power - TTC-SC28 by Justin Pavelko

When ordering I knew the batteries are not included and that they are 18650 lithium. First, I knew they weren't cheap, but they used them for two reasons. First, 18650 lithium works better than alkaline at low temperatures, and 18650s have about 2600mAh, which is close to alkaline, but they work better in cold air. Also, you should get about 200 charge cycles. Besides batteries, I use it in a bar fridge in the office. At low level, it lasts about a week, even the temperature seems to come out. Load them all up. One minus point - you can hear it working when it's quiet. Maybe that's good.