3.1.2 Battery Charger

AVR-IoT Cellular Mini features an MCP73830 Li-Ion/LiPo charger and a JST battery connector on board. The charger is configured to limit the charge current to 196 mA to prevent overcharging small-capacity batteries. The charge cycle is configured to terminate when the charge current falls below 37 mA or if the charge cycle is longer than the safety timer of four hours.

Info: The minimum recommended battery capacity is 100 mAh to prevent charging the battery with currents above two times the battery capacity.
Warning: MCP73830 has a battery charge voltage of 4.2V. Make sure your battery is rated for the same charge voltage.

The battery charger will enter a preconditioning mode if the voltage at the VBAT pin is less than 3.5V. In this mode, only 10% of the fast charge current is supplied to the battery. The preconditioning mode has a separate safety timer of one hour. If a charge cycle does not exit this mode within the timer window, the charge cycle terminates. If the preconditioning safety timer is triggered, it may indicate a faulty battery.

Warning: Make sure to check your battery’s polarity before connecting it. There is no reverse current/battery protection circuitry on the board.
The battery charging circuitry includes one red LED to indicate the charge status. See the table below:
Table 3-2. Charge LED
LEDCharge Status
OnPreconditioning, constant-current fast charging, or constant voltage charging
Off No battery present, shutdown, charge complete, or timer fault
FlashingA preconditioning timer fault may indicate a faulty battery