Ran across a bad lipo, brand new, thought I'd share what I found. I noticed this lipo had a bulge, a ridge on one side, when I ran my finger across it, it felt like there was a wire that had gotten sealed inside. At the time I didn't think it was really bad, I planned on making a parallel pack out of it, took the blue heat shrink wrapper off, unsoldered each cell, for some reason, I decided to check the voltage of each individual cell, what I found was the cell with the ridge was flat, zero voltage, but when by accident I touched the probe of my meter from the neg post of the dead cell to the poss post of the cell next to it I got 2.48 volts, how can that be?? I unwrapped the cells the rest of the way and separated them. They were really stuck hard together, that shouldn't be... When they finally separated that's when I discovered the corrosion between the cells, the plastic insulating coating on the cells had been eaten away and were fused together, voltage was leaking from one cell to the other
through the foil wrapper. I salvaged the one undamaged cell, I'll use it to make a 4s pack with another 3s pack. I'm glad I found this before I put it in a
mod and charged it, who knows what would have happen... I'm glad something made me check the voltage of each cell, if I hadn't I probably wouldn't have caught it. My new rule, if a lipo doesn't look right, when in doubt, toss it out.