Voltage and battery alarm problem

Having trouble with my low battery alarm going off way too soon. I believe I have all the Power parameters set correctly, but the buzzer goes off after a minute or two.

Number of Cells - 4S
Full Voltage / cell - 4.2
Empty V / cell - 3.5
Voltage Divider - 13.65333366

Is the voltage displayed in QGC correct? If not, you can use QGC to calculate and correct the scaling parameter.

Is this on a Pixracer board? I’ve seen a few Pixracer boards complain about avionics voltage low, when it’s not really. I fixed it by changing the voltage divider on the board to compensate for diode drop. Let me know if you need details.

I have a similar issue.
I get a constant beeping alarm and commander denies arming due too low battery, however QGC reports that the battery is at 100%.

I’ve measured the voltage and it agrees with with what QGC is reporting.

Not sure how to correct this, confused by the inconsistent behaviour…
Power Settings

Safety Settings:

Commander output:

Battery related parameters:

Any tips?

What kind of battery you are using? Why the full charged voltage for a cell at 5C load is set to 3.60V? that seems bit low for normal Lipo battery.

I wouldn’t focus too much on the actual values, they are based on this:
But that’s not really what I’m worried about here, I’m not trying to get the perfect values for the parameters.

What I’m trying to understand is what is causing the alarm when the battery is 100% according to the values I’ve set.


that might be some issue with the flight controller, either hardware or firmware. What hardware/firmware you are using? try to update to latest master to see if improved.

But the value of 3.6v does not seems to be a reasonable one. a 3S Lipo battery fully charged voltage normally is 12.6V. if your battery measures only 10.91V at disarmed status, that is almost drained.

I’m using a Pixhawk with PX4 flight controller, with a one month old build.

On the link I gave you they explain the reasoning for the values, I’m happy to take their word for it. Take a look at the bottom two examples, they use the same values I do.

But again the issue here is not finding the correct values to set the alarm to, but the behaviour of the alarm.

Did you first Power the FC via USB and then only plugged in the Battery? If this is the case this behaviour is normal.

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Ah… that is certainly possible, I thought I was connected via radio link, but not 100% sure. I will keep that in mind.

Hi , I am having similar problem, anyone was able to solve this one?

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