[suicideneil]

The softer cell will be the bad one obviously, and if you remove the shrinkwrap, and use a voltage checker (plugs into the balance tap), it will read out the voltages of each cell in turn. The bad cell will hold its voltage though, but will always puff up during a run, then settle back down afterwards, as several have reported. I would suggest contacting maxamps about it- you may be able to slpit the packs up and remove the dud cell, though they may be stuck together too well and the dud cell cant be seperated. if you could seperate it, you could build a 4s pack, or simply replace the dud with a new cell, and have a 5s pack again.