Common Power Module¶
Many autopilots can be purchased with an analog power module that provides a stable power supply to the autopilot and also supports measuring the battery voltage and current consumption.
Below are typical limits but it may be best to confirm directly with the vendor:
- Maximum input voltage of 18V (4S lipo)
- Maximum of 90 Amps (but only capable of measuring up to 60 Amps)
- Provides 5.37V and 2.25Amp power supply to the autopilot
The Power Module provides enough power for the autopilot, receiver, and a few low powered peripherals (lidar, telemetry) but does not have enough power for servos or high current devices like FPV transmitters or the RFD900 radios. More information on powering the Pixhawk can be found here
Connecting to the autopilot¶
The 6 pin cable from the power module plugs into the POWER port of the autopilot
The battery is connected to the power module’s male connector. The ESC or Power Distribution Board should be connected to the power module’s female connector.
Most ground stations provide a battery monitor interface but the parameters can also be set manually:
- BATT_MONITOR = 3 to measure only voltage or 4 to measure both voltage and current (you will need to reboot the board after changing this)
- BATT_VOLT_PIN = 2. The autopilot pin connected to the power module’s voltage pin
- BATT_VOLT_MULT converts the analog voltage received from the power module’s voltage pin to the battery’s voltage
- BATT_CURR_PIN = 3. The autopilot pin connected to the power module’s current pin
- BATT_AMP_PERVLT converts the analog voltage received from the power module’s current pin to the battery’s current
- BATT_AMP_OFFSET voltage offset received from the power module’s current pin when ther is no current being pulled from the battery
Dual Battery Monitoring¶
If the autopilot has additional analog-to-digital pins available, a second battery can be monitored by setting up the
BATT2_ parameters. The values below allow reading a second battery’s voltage and current using The Cube’s POWER2 port.
- BATT2_MONITOR = 4 to measure both voltage and current (you will need to reboot the board after changing this)
- BATT2_VOLT_PIN = 13
- BATT_CURR_PIN = 14