I’ve been working with the Pixhawk now for about 6 months of off an on flying of a hex based on the Tarot FY680 Pro frame (extended to 815mm or so).
Last night I was calibrating the PM on mission planner for volts and current. At resting voltage I got a good reading on a 4S Zippy 8000 maH battery (about 16.7V) and calibrated using the mulitplier. The current draw calibration seemed pretty close, so I left it there.
While doing the current draw test to calibrate, I noticed that the voltage reported to MP on a load was not accurate based on the tester I used to check the load. The MP would report numbers in the 14.9V range on a full throttle load, however, the tester reported about 15.9V during this same period.
Initially, I had a failsafe for low battery for this very reason, but also for this same reason I turned that failsafe off and started using one of the little LiPo battery alarms as every time I would fly I’d receive a battery failsafe fairly quickly. Sometimes when the battery reports about 80 percent, a full throttle load reduces the reading to 14.0V when the meter reports closer to 15.0V.
Could this be a defective module? I’ve purchased a smart port voltage meter for my Taranis setup since it reads voltage from the balance ports (like the little LiPo alarms) and I can have the telemetry sent back to the radio to monitor voltage this way.