Crazyflie Battery Connector Disconnecting

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DimChaik
Beginner
Posts: 8
Joined: Sun Nov 01, 2020 1:57 pm

Crazyflie Battery Connector Disconnecting

Post by DimChaik »

Hi all,

I have noticed something with my crazyflies. After about a year of lots of flights, there is a certain issue that arises with the battery connector.
Specifically, whenever you jingle the cables (or the crazyflie moves), the battery apparently disconnects. To be clear, the connectors do not visible detach, but apparently the connection has degraded and the power instantaneously is lost, with the result of the crazyflie resetting.

Now this is the third crazyflie this issue appears in. For the previous two, I replaced the cables entirely from the body of the crazyflie. In this one, I'm wondering if I can simply replace the white connector on the crazyflie's side and see if this fixes the issue. If not, it means that it's not the connector's pins that degrade over time, but the cables attached on the PCB themselves.

Has anyone else had this issue? Also, do we know if the white connector can be removed without cutting the cables?
tobias
Bitcraze
Posts: 2339
Joined: Mon Jan 28, 2013 7:17 pm
Location: Sweden

Re: Crazyflie Battery Connector Disconnecting

Post by tobias »

Well this is something new to us. We know the contact resistance can go up with aging due to oxide layer but we have not experienced any total disconnects. Could you try to apply some contact cleaning fluid or e.g. WD-40 and see if that helps. Do you have any pictures of the pins you could show?

It is possible to remove the white part of the connector by pressing down the locking tabs that are visible in the middle of the connector and pulling out the wire.
DimChaik
Beginner
Posts: 8
Joined: Sun Nov 01, 2020 1:57 pm

Re: Crazyflie Battery Connector Disconnecting

Post by DimChaik »

Hi Tobias,

thanks for replying. Sadly I already removed the cables of the defective drone, so I can't test the WD-40 solution.
But I have attached a video link, of the behavior I was talking about. The video shows a normally working crazyflie, but imagine that in the defective case, the crazyflie powers off/on all the time while you do such movements. That is, the two connectors never visibly come apart, but apparently connection is instantaneously lost.

That's why I assume it is either the pins in the white connector, or the cabling itself, that degrades over time. And this is the third drone this occured in.
Granted, all of the drones that eventually had this issue, have been through countless hours of flight and a lot of small-scale crashes, due to the novel research they are being used in, which makes those crazyflies the first testbed for a lot of algorithms, leading to a bunch of crashes now and then.
But still, I thought it important to note, since it has occured three times.

https://www.dropbox.com/s/yof2ma1txq3gj ... 1.mp4?dl=0
tobias
Bitcraze
Posts: 2339
Joined: Mon Jan 28, 2013 7:17 pm
Location: Sweden

Re: Crazyflie Battery Connector Disconnecting

Post by tobias »

It is hard to say what the real problem is without having the defective cable. As you say, it could be the connector, the cable itself or even the soldering to the board. On the Crazyflie 2.0 the cable sometimes broke just before the soldering point but that problem we have not seen on the CF2.1, until possibly now.

My guess is that is it the cable. Do you swap batteries a lot and if so is the cable bent back and forth? The CF2.1 has a silicon cable to allow many bends but eventually it will wear out too.

If you have the problem again we would really like to have a look. Then please send us an email to support@bitcraze.io and we will arrange something.
DimChaik
Beginner
Posts: 8
Joined: Sun Nov 01, 2020 1:57 pm

Re: Crazyflie Battery Connector Disconnecting

Post by DimChaik »

Hi Tobias,

You are spot on. I tried to simply replace the white connector first, but the issue persisted, so it wasn't the connector.
The soldering on the PCB is also very solid.
Then I removed a bit of the AWG-20 at the end of the cables, and lightly pulled on the inner conductive material.
The red cable was strong, but in the case of the black one, a fair length of cord was simply removed from the cable - a separation had apparently occured, exactly due to the constant bends you're talking about.
So I simply removed more of the AWG until I reached solid cord, and attached a new cable at that point. Now it works fine again, and I expect it will for a while, cause the other two CFs I had to do this to, have already been flying fine for a few months.

I appreciate you wanting to look into it, but since it's a case of the cable wearing out over time, I don't see how you could do anything about it from the side of Bitcraze, given that it was neither the connector part nor the soldering.

Cheers, Dimitris.
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