Tuesday 19 January 2016

Cheerson CX-10 - Flying below freezing

Finally winter is here!

Complete with snow and everything. So last weekend we tooks the skis and the sled and, of course the CX-10 C drone. (See here for a review in my blog or the video.)
A good opportunity to shoot some spectacular footage of the kids racing down the hills.
Or that's what I thought.
I thought I had the CX-10 C charged up at home and put it in my jacket's outer pocket. So I was amazed that it started flashing a battery warning at me the moment it took off.
After only seconds of flight, it was unable to gain altitude and dropped to the ground.
So I took it back home and the CX-10 C was well again, down in the comfortable 20C of the secret underground lab.
I had expected a somewhat reduced flight time, but nothing that drastic. So to double check I took it out for another test flight later yesterday evening.
Really cold now.
Too little flight time for good shots

EDIT 20160119: Bangggod has the CX-10 C on sale this week for under 20€

The construction of the battery compartment might be good for higher temperatures, but it obviously is a bad idea below freezing. The fans will also add to the cold airflow.
The battery is exposed to the elements.
So my first attempt to improve winter performance is to put some 10mm Kapton tape over the grids to keep the battery warm. All flights have been made with the microSD card inserted, but no recording active.

Setup Batt.tmp Env.tmp Flight-time
No insulation +20C -3C 1:40min
No insulation -3C -3C 0:25min
Kapton tape +20C -3C 2:15min(1)
Kapton tape -4C -4C 0:20min(2)
Indoor flight +20C +20C 2:40min(3)

(1)=Battery warning flashing after 2min. Could not hold altitude after 2:10min. The charge meter showed 60mAh in the subsequent recharge.
(2)=Battery warning flashing after after a few seconds. Could not gain altitude at all. The charge meter showed 12mAh in the subsequent recharge.
(3)=Recharge cap 81mAh after flight

This tape does not add much weight

I conclude from these tests that it makes sense to keep the battery warm (who would have guessed) and to ensure it stays that way as long as possible. I was hoping that a cold, insulated cell would heat up due to the higher internal resistance. But that effect seems to be neglegible here.