Bitcraze Forums

Is the battery charging handled in the regular firmware or in a separate circuit?

Or in other words, if someone messes up the firmware, is it possible to overcharge (=explosion) or deplete (=dead battery) the LiPo battery?

If I use a stronger USB power supply (2A), does the Crazyflie limit the current to sane values? The specs say that the battery allows for 2C of charge current, which would be 480mA.

Is there documentation on how the charging algorithms are implemented, or should I look directly in the source code?

There are two circuits that handle it. There is a PCB under the yellow tape on the battery that protects it from overvoltage, undervoltage, shorts, etc. Then there is the charging circuit, a TI BQ24075 that handles the charging. You can have a look at the schematics here.

The USB input is set to 500mA now but as the system consumes about 100mA, 400mA goes to charging. One thing that is not implemented yets is to enable 500mA input when the CF2 is off, then almost all 500mA can be used for charging.

The low level power management is handled by the nRF51 firmware. This can't be updated with USB, only with Crazyradio or with a SWD debugger. The STM32F405 can control some of the things as well.

No documentation yet

Thanks for the information