Zino Mini: Solving the "battery deviation" issue (and upgrading the battery in process)

[UnknownUser000]

Hi everyone, this is my first post here. I decided to make it for people like me who have been struggling with their Zino Mini SE/Pro batteries.

I've bought a Mini Pro in 2022 and it arrived with two unbalanced batteries, one of which was completely dead and not even reacting to the charger. The other one showed "battery deviation is too large, please recharge before use" error in Hubsan 2 app and even completely recharging the battery didn't solve it.
Recently my third battery also showed this error message and I decided to take another chance at repairing it. I bought two 3400mAh 18650 cells, connected them in series and soldered a middle/balance wire between them. Then I disassembled the drone's battery, soldered the GROUND, then MIDDLE/BALANCE WIRE, and only then POSITIVE contacts ALONGSIDE THE EXISTING CELLS already connected to the battery controller board. Then I carefully removed the old cells, re-assembled the battery and reset the controller by short circuiting the two contacts of a big SMD capacitor near the thermal sensor pads. If you have a small reset button, just press it once and wait a few seconds. Then put the battery onto the charger.

Important notes while repairing the battery:
1) NEVER disconnect the original cells while replacing them with new ones. Do it only AFTER the new cells are soldered and attached. If the battery controller is completely disconnected from battery cells it BRICKS itself without any possibility of restoration. This happened with both my batteries which I had earlier.
2) ALWAYS BE CAREFUL while repairing the battery. If you accidentally make a short circuit anywhere, the battery controller will most likely go up in flames and die. This HAS happened to me as well.
3) After replacing the battery cells, CHARGE THE BATTERY TO 100%. The controller will balance the new cells and you'll have a perfectly working battery!

[UnknownUser000]

Helpful videos:
https://youtu.be/iyylkN5vTk8
https://youtu.be/cilB3eX_sDQ