[Dragonfly DIY] Easy repair: Cycliq Fly6 battery replacement

The Cycliq Fly6 is a rear camera for bicycles. I've owned mine for about a year and a half, and when I tried to use it this spring, it wouldn't turn on. A few rounds with Cycliq support on things to try didn't work.

The problem was just a dead LiIon cell that would no longer take a charge. The camera has a rather large quiescent current so for future reference, when storing for a long time, charge it up all the way. It draws 70 microamps so if you store it near dead it'll damage the cell before spring.

Anyway the repair cost $5, which beats buying a new camera for $140 (to their credit, Cycliq did offer to sell a new unit to me at a substantially reduced cost, but luckily I didn't need it).

The Repair

If you're going to replicate this repair, please use caution with the batteries. These are unprotected LiIon cells, not normally intended to be handled by untrained people. If you short them out they can get very hot very fast, and may even burst or catch fire.

Remove the microSD card before proceeding, it'll get in the way.

The Fly6 comes apart very easily. On the back are four holes with little rubber plugs in them, in the corners. Pick those out with a small tool, and you'll find four screws. Remove them, and the front cover comes off. BE CAREFUL there is a flex cable between the front panel and the main board and it's easily damaged.

There are three screws holding the main board in. Remove them and carefully pull out the main board. It has some wires going to the back so it can't be removed but you can get it out of the way.

Finally you will get to the battery. You can try measuring the voltage where the battery connector goes on the main board (be careful, don't short the pins). On mine it was almost zero, something like 400mv. Lithium cells should never be < about 3.2 volts so it was clearly dead.

Unplug the battery, take two more screws out that hold the strap that holds down the battery, and remove it from the unit

You'll need an 18650 cell with tabs on it to solder to. I got two of them from Amazon for $10. The brand I got was HyperPS - that isn't critical but check reviews, there are a LOT of junk 18650s out there. You want about 2500 mAH. If the cell says it's much over 2800 and it's not pretty expensive (like $12 or more) it's almost certainly junk.

Anyway, you will need to remove the wrapping from the original 18650 cell and save the strap and circuit board and wires. Cut the strap leaving most of it attached to the circuit board. Again, be careful during this and subsequent steps to avoid shorting the cell.

I used a couple of test leads to attach the battery circuitry to the new cell and test things before proceeding. I measured the voltage on the cell, plugged it in and confirmed that it was slowly charging (another 1/100th volt every few seconds). Unplugged and powered up the camera. Once convinced it was working I proceeded.

You need to be CAREFUL here. The case is negative. You MUST NOT allow the positive to short to it. Use some kind of good durable tape (I used two small squares of Gorilla tape) under the positive terminal before soldering, otherwise the heat of soldering will melt through the battery wrap, short the battery out and you'll have a sizzling tube of unhappiness in your hands.

With the tape in place, solder the board from the original battery to the new cell:

Now you need to wrap the whole package so the bare straps can't short to anything. The tape must be thin or it won't fit back inside the case. I used Kapton tape because I had some. Any thin tape, even painter's tape, should be good.

Now re-insert the battery into the case, with the circuit board tucked towards the bottom corner where there's room for it and reattach the battery hold down strap with two screws:

Fit the main board back in place, screw it down with three screws. Check the lens for smudges and dirt, clean if necessary, and then replace the front and secure with 4 screws and replace the rubber plugs.

Put the SD card back in and confirm operation.