Temperature dependency - copter not booting when cold?

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Lecostarius
Posts: 46
Joined: Mon Oct 20, 2014 11:29 pm

Temperature dependency - copter not booting when cold?

Post by Lecostarius »

Hi everyone,

I encounter the problem that my copters are not booting up properly. I have the assumption that it is related to temperature - they are always booting without trouble when it is warm (indoors), and often have trouble when I try to fly outside when it is cold. When I bring them back into the house, it takes them two or three minutes to warm up, after that, they boot without problems.

The status when booting fails is such that the main loop is running and stick controls are accepted, but the copter will not arm. I think it could be related to some sensors not initializing properly. This is pretty inconvenient since I have to connect the battery and boot the copter in the warm, and then carry it outside where I can fly (once it has booted properly, it flies without problem, no matter how cold).

I am flying both a CRIUS AIOP v2 and a Drotek board DroFly Pro v2. Same behaviour essentially with both. So it could be the 6050, the Mag, the microcontroller - those two boards share all these components.

Does anyone have similar experiences, or can give an explanation what the reason is? So far I have not done any research, just wanted to ask in case this is a well known problem.

Thanks for any feedback!

Leco

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Leo
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Re: Temperature dependency - copter not booting when cold?

Post by Leo »

I can't help you directly however I am flying my QC with a Crius AIO Pro v2 in 2°C temperature and I'm having no issues.

Leo

waltr
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Location: Near Philadelphia, Pennsyvania, USA

Re: Temperature dependency - copter not booting when cold?

Post by waltr »

It could be a few things. Maybe it is your TX stick values have shifted with the cold and now either Yaw max or Throttle Min are not exceeding the min_check or max_check values required for valid stick commands.

Lecostarius
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Joined: Mon Oct 20, 2014 11:29 pm

Re: Temperature dependency - copter not booting when cold?

Post by Lecostarius »

Thanks for the input, I did not think about that. Way to try without oscilloscope would be to keep the TX outside for 30 min and the copter indoors, and then try to fire it up with the cold TX. I will try and report the result.

Cheers, Leco

waltr
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Re: Temperature dependency - copter not booting when cold?

Post by waltr »

Lecostarius wrote:Thanks for the input, I did not think about that. Way to try without oscilloscope would be to keep the TX outside for 30 min and the copter indoors, and then try to fire it up with the cold TX. I will try and report the result.

Cheers, Leco


I was thinking this would be a way to test that theory.

Lecostarius
Posts: 46
Joined: Mon Oct 20, 2014 11:29 pm

Re: Temperature dependency - copter not booting when cold?

Post by Lecostarius »

I still do not know the reason, but it is not the Transmitter. I put the copter outside and kept the transmitter indoors in the warm, and the problem appeared again. So it is most unlikely unrelated to the radio.
If I eventually find the reason for that problem I will post it here.

-- Leco

waltr
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Re: Temperature dependency - copter not booting when cold?

Post by waltr »

Ok, thanks for reporting back your results.
It does sound like it is the FC board. Could be the XTAL drifts badly with temperature or there could be a bad solder joint that acts up when cold.

I have not had problems with any of the FCs I run in the cold.

Lecostarius
Posts: 46
Joined: Mon Oct 20, 2014 11:29 pm

Re: Temperature dependency - copter not booting when cold?

Post by Lecostarius »

I found a clue to what stops my copter from booting in the cold: I think it is the accelerometer.

I connected a cold, non-booting copter to MultiWiiConf and found that the ACC reading indicated that the device was tilted 90 degrees (which it wasn't). The ACC reading would also not change over time, but was stuck in this position. Since I have the option active that the copter will not arm when tilted, I could not arm under this condition, and got the impression that the microcontroller has crashed - which was actually not the case.

A simple "calibrate ACC" from the MultiWiiConf brought the ACC back to normal. I will try whether the stick command has the same effect.

Still the exact root cause is unclear to me - could it be that the tiny masses inside the ACC chip somehow freeze at low temperatures? Did anyone experience similar problems?

I am using the standard 6050 6-axis IMU.

Cheers, Leco

waltr
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Re: Temperature dependency - copter not booting when cold?

Post by waltr »

That could be the case or it is with just the one you have on that board.
I have been flying this winter at temperature below freezing without issues. Different FC boards but all use the 6050 acc chip.

When the Acc is 'stuck' are there any I2C Errors?
If you can try a different board.

pihlerm
Posts: 23
Joined: Tue Dec 09, 2014 6:40 pm

Re: Temperature dependency - copter not booting when cold?

Post by pihlerm »

Hello,

I have a AIOpro from HK board, running Multiwii 2.4.
I have a custom copter type and mix, using 3 motors and 4 servos.

I have a problem in cold weather: two of the three ESC's (motors 1&2) are not booting .. the ESC's dont initialize (like there is no PWM signal) (no beeps when power on).
The third ESC always initializes without problems.

This only seems to be a problem when the board is cold (~5 deg C), if warmed up to ~20C they all initialize.

What could be the problem?

BR, M.

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