hello all. I recently purchased(5 days ago) a great planes bp1250 7.4volt lipo. As soon as I got it, I put it on my great planes polycharge charger(the simple one), and also had a great planes equinox balancer hooked up as an interface through it. Well, it only took about 5 minutes to charge the battery, and I flew it down about a quarter of the way. I then flew it again, and had about a quarter of life left in it. So I put it on the charger, and only one of the cell leds light up. Cell 2 lights up, but not cell one. So, I checked the voltage in each one, and one was at 8 volts, and the other was at 4volts! I am now completely clueless, because in the directions/troubleshooting guide, says that if the cell deds do not show the correct number of cells in the battery:

bad cell in the pack
incorrect adapter harness used
bad connector on battery, adapter or equinox
cell coltage too low for equinox to detect
I know it isn't the incorrect adapter harness used, and the cell voltage isn't too low for equinox to detect, because both cells are above 3 volts. So, it is either bad connectors, or a bad cell.
How can it get that far off so quickly? I know I should have checked the voltages right when I got it. Please, if you have any advice or information, please help!!! thanks, Joe