You can use rechargeable AAA lithium batteries to power Pocket Radar products. Rechargeable batteries will not operate correctly with the battery monitor/battery indicator on the radar because it is designed for Alkaline batteries. Lithium batteries have a regulator chip that holds the voltage constant at 1.5 volts until they are dead. This means the battery indicator will read 4 bars even if you only have 1 minute of battery life left.
Rechargeable AAA NiMH batteries provide 1.2 volts of power which results in the battery indicator starting at 3 bars. Due to this voltage difference, the radar battery indicator will never show 4 full bars.
You will need an external charger for your lithium or NiMH rechargeable batteries; you cannot charge them inside the radar.
If you have a Smart Coach Radar model SR1100 then we recommend using an external USB Lithium Power Bank as your source of power. You'll need a micro-USB cable to connect the Power Bank to the port on the side of the radar.