I’m starting to build an Arris m900 quad. I plan to use a Pixhawk 6c. Motors are Eaglepower EA50 220kv with 40A ESCs. I have a PDB that came with the frame kit. I need a power module that will work for this model. I’ve only ever used a Holybro PM02 and I’m pretty sure that can’t handle the current flow of this build. Any recommendations on what would be a good one to go with?
Holybro Pixhawk 6c and PM02 are sold together. PM02 can not handle Pixhawk 6C? Why?
You can check the following:
The PM02 does connect to the Pixhawk 6c but it’s not rated for the larger current draw that this drone will draw.
Consider the Holybro PM08. I’ve used it and it’s heavy, but it can handle big currents for a decent price. Alternatively, you can measure high currents with a bypass, although I don’t recommend it.
Just to make sure I understand these power modules correctly, do they measure the total amount of amperage draw going through it or are they measuring how much one motor is drawing, i.e., total amps divided by four for a quad?
In general, the power module does the following
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provide adequate power to the Pixhawk.
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monitor the battery
If you only expect it to do 1, it doesn’t matter where you plug it in. However, if you expect it to do 2, you have to connect it where the power going to all the motors passes through.
Voltage alone is enough to monitor the battery to some extent. However, for additional features such as accurate battery usage and compensating for compass interference based on power usage, the power module should be connected where all power passes through.
Right, I get that they can power the FC and I plan to use it for that. I also plan to use it connected between the battery and the PDB. I guess what I’m trying to sort out in my mind is what amperage does the power monitor read? I’m assuming that it measures the amperage draw from the whole PDB which would be made up of the draw of each motor x 4 since that’s how many motors I’ll be running.
Well if the battery is connected directly to the Power module it’s reading total current… Not really understanding the question. These modules have one sensing device, shunt resistor or Hall effect, so that’s all it can provide.
That’s what I had figured but just wanted to make sure. My current quad is reportedly only drawing 15-18 amps. That’s what had me wondering because that means that those motor/prop combos must be pretty efficient.
You need to calibrate the current sensor. It’s easy to do. Use search here for “current sensor calibration” for the battery logged/charged mah method.