[SOLVED] How to change the charging current

[mf2909]

Hi,
for our application of the Crazyflie we have some external components mounted on the drone which consume not a lot, but still a noticable amount of power. We can not use them on the 3V pin, and when using the VCOM Pin to power them, the Battery charging is almost not happening over USB (The log shows 0A charging 90% of the time and some spikes up to 0.05A for a few milliseconds). So we decided to wire the components directly to the battery. But when doing so, a lot of the charging current, which seems to be limited at 0.3A, is going into these components, so the charging is still very slow. We would like to charge at somewhere around 1A. It seems like the BQ24075 is capable of doing 1.5A so we hope that would be possible. Could someone explain if we have to change a resistorvalue or some values in the firmware for achieving the higher charge current?

Thanks a lot,

Max

[tobias]

Yes you can change the charge current to ~1A by changing the nRF51 FW and defining ENABLE_FAST_CHARGE_1A. Since charging faster will heat up the board more you should probably disable the temp check as well by defining DISABLE_CHARGE_TEMP_CONTROL.

[mf2909]

Hi Tobias,

thank you very much, that did the trick! We did not want to disable the temperature check completely, so we only raised the limit slightly, now everything works perfectly.

[tobias]

Great, glad it worked out!