Removing a bad cell from a lithium-polymer battery
One of the cells in my lithium polymer battery rapidly started losing capacity a few days ago. I ordered two new batteries, but I needed power in the meantime.
It was trivial to open up the battery and remove the faulty cell, since the other three cells were fine. The battery is now effectively a 3-cell battery, which is not as efficient, but it will do for now.
The imbalance probably resulted from my neglect. Especially considering that I used the battery without any kind of low-voltage alarm, I probably drove some of the cells below 3 V during use. Furthermore, I never balance charged the battery (which I always will from now on), so the small imbalances built up to a serious amount.