A mess tidied up for the day. Not done with the shell replacement though, will continue tomorrow

Contents continued

Btw, this is a 70mai Dash Cam Pro Plus+. If someone has the same issues, this is how to open it up: peel off part of the sticker on the back, it has two screws, remove them (phillips 00 screw). Then use a pick or similar to undo the upper tabs. It has two more tabs at the bottom.

As I reconnected the battery to the dashcam it started working normally: it recorded video, it took a charge, the buttons were working. Things that just with USB power alone were not happening.

Once I soldered the wire to the correct pin, the battery now measured 3.2V, which is really low for a 4V battery, but more normal than 0V. This is a picture of the way the wires are connected to the battery. Sorry if it is not super visible, as I took these after I fixed the dashcam

As this is a lithium battery, I very carefully desoldered the black wire from the incorrect pin, applying heat just for long enough for the solder to melt and immediately pull the wire. Then I let it rest for a while. I don’t want any of that heat being conducted down to the actual battery

Only that the black wire was soldered onto another non power related pin instead of the negative one. This was like this from factory, not sure why.

As you can see in the second picture, there is a set of wires coming out of the battery, and those wires were soldered onto a PCB that was also soldered onto pins on the battery. Those pins were obviously the positive and negative that would go to the red and black wires respectively

I opened it up without a clue of what could be wrong. First thing I encountered was the battery when I opened it up, so I measured it: 0 volts. Hmmmmmm that’s not normal

Forgot to add a picture of it turned on :)