PreArm:Battery 1Low voltage failsafe

Flew my Quad yesterday and keep getting the “PreArm:Battery 1Low voltage failsafe” warning. Resetting the battery allow me to re-arm the quad and do another flight but keep getting some error messages during the flight and after landing the failsafe prevent me again from re-arm.

Is this due to the temperature been -2C and the battery (a 3S 5000mAH Hen-Ace) exposed to the elements?

Edit: In the Parameter Set Up I have 4 cell. I am not able to change this… Could this be a reason for my issues?

Post your parameter file please, just to make sure we dont tell you the wrong thing.
Or a link to the .bin log file

Also specify your prop size, and did you do the initial parameters setup at all?

@xfacta, Shawn,
The .bin and parameter file is found here:
Parameterlist EDU450.param (17.6 KB)
2021-12-29 09-46-43.bin (303.5 KB)

The quad is a HexSoon EDU450 and I used the initial parameters from the parameter list for the quad (HEXSoon EDU450) found in Mission Planner.

Prop size is 10x5 (I think, doesent say on the props…)


You nearly had the correct settings for 3 cell lipo
Usually you would set these too

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Awesome, thanks. Will get that corrected right away. No flying today as it sh## wx. Will test tomorrow…


@xfacta - I did the suggested changes, but got the Battery failsafe again… Strange

Can it be that the brand new battery is faulty?

A fully charged 3s should be close to 12.6v, if its dropping to 11.3v before you have even taken off means your batteries are far too cold to fly, you SHOULD NOT attempt to fly with batteries below 15c. they cannot sustain high power loads below that temperature, and at -2c you will be lucky for it to even take off. DJI sell battery heaters for their machine for this reason, their smart batteries wont even switch on if they are too cold.

something like this is what you need.

@geofrancis - today its a lot warmer, probably 6-7C. So I am unsure if temperature is a major issue now. Is 6-7C to cold as well?? (If so, I will consider the heater you linked to…)

Changing the BATT_LOW_VOLT,10.8 setting fixed part of the problem, but not all…

that is still far too cold. your batteries need to be above 15c before you take off, usually once your in the air the constant discharging will keep them warm. if you try and take off with cold batteries the voltage is lightly to plummet immediately, Bypassing the prearm check is lightly to result in a very short flight at best or a crash at worst.

Understood. Will have a focus on keeping the batteries warmer. thanks.

Dont change the battery thresholds, check that the paower brick voltage measurement is accurate.
If the voltage reading is accurate then you have a temperature problem, or the battery is faulty.

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At that temperature I just keep my batteries in my pocket before I use them. Or if they’re too big for that I keep them in my vehicle in the sun. It is true that batteries need to be warm, but they will work below 15c. However you need to have realistic expectations of performance when the temperature drops. I don’t start a flight with a cold battery with a full throttle punch. I know my flight times are going to be less. I watch battery voltages very closely, and also watch for voltage sag during high power settings.

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these look like they could be used for a cheap diy battery warmer

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