Pixhawk Backup Power Concern and Question

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1

Just a question and update. I power my pixhawk with the 3DR power module . But let’s say I want a backup power in output rail or I am running 6S. Here is the problem and I tried this on BOTH of my Pixhawk units. If you power just from output rail the unit switches from Green to Yellow with a low voltage alarm. I am putting 5 volts into the output rail. The HUD tells me it’s only 4.1 volts. Same thing if you power from both the 3dr PM and the output power and cut the 3DR power. It’s stays on but alarm trips. Does the output rail need more the 5 volts input? I am concerned that if I lost the 3DR PM in flight would the alarm trip and Quad lose power? Also, I have 2 vehicles on 6S and want to power with a BEC since the 3dr power module handles 4S max. Any suggestions?

Thanks JEFF

2

Hi Jeff,

This behavior is normal when you have the voltage & current monitor enabled, when you cut the power from the Pixhawk’s power port it will trigger the battery failsafe (and will draw the power from the output rail to perform the task).

You can use another voltage and current monitor that supports your 6S battery, here is the documentation on how to use it:

copter.ardupilot.com/wiki/common … to_Pixhawk

If you don’t have voltage & current monitor but want to power the Pixhawk from a BEC then you will need to disable the voltage and current monitor but you won’t be able configure the battery failsafe.

Related info:
copter.ardupilot.com/wiki/common … m_the_ESCs
copter.ardupilot.com/wiki/batter … y_Failsafe