When I get off work today I will start unplugging things one by one to find a power drain
Found this, I wonder if its why
Re: Pixhawk 2.4.8 missing components vs 2.4.6
The missing components seem to be the ideal diode controller and its mosfet group highlighted in red that allows pixhawk to utilize triple redundant power supply and protect it in case of overvoltage. Be careful with this one if you decide to power it from multiple sources at a time.
The missing chips highlighted in blue are the logic level translators that tie 3.3v logic levels of the pixhawk MCU to 5v logic that is common for servos and ESCs. They also shield the MCU from possible interference coming from servos and ESCs and protect against voltage spikes. A regular pixhawk has those chips on all its serial ports as well.
https://www.rcgroups.com/forums/showpost.php?p=34502984
https://www.rcgroups.com/forums/showthread.php?2619058-Pixhawk-2-4-8/page5
also found this. I know very little about electronics but if you can you solder, maybe try what this guy did? Just lg33’s, I’d be hesistent to remove components without someone knowledgable chiming in. Components can’t be very expensive https://www.rcgroups.com/forums/showpost.php?p=34860279&postcount=178
I have used several of the cheapest Power Modules around and never saw this problem. With those Pixhawk 2.4.8 also when I had them flying.
Drone power problems
Testing pixhawk power draw
All power draw disconnected 4.89 volts
Receiver 4.85
Ts mini 4.82
GPS 4.78
Telemetry module 4.76
Bec 5.27 not connected to pixhawk
Bec diode and capacitor connected to pixhawk 5.26
I’ve been adding sensors to my old pixhawk and started to notice the voltage has dropped when connected to USB. I added a lidar and second gps. Now its in the 4.7v neighborhood. I get 5.0-5.2v when under normal battery power. It sounds like you’re drawing more power than the Pixhawk can provide, as evidenced by when powering the servo rail, voltage returns to normal (that’s what you mean by diode and capacitor right?) and no one sensor appears to be the culprit from your readings. If you supply power to the servo rail, and its higher voltage than the power module, it’ll switch to the servo rail. Same with the USB, if that’s higher, it’ll switch to that. You can power off the rail but you’ll lose the redudancy since there looks to be a problem powering from the power module on your craft
What voltage do you get when powered by USB?
Yes when powering the servo rail and I only get 4.5 with usb