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

have you tried using the equinox without the charger to balance the pack before charging it?

yes, only the second cell led shows on the quick balance, and the interface. Thanks, Joe

well, I called great planes, and had a conversation with a person that knew basicly everything I was talking about. In the end, they are sending be a new battery, and if the problem is still there, I will send in the equinox balancer, and they will take a look at it. Joe

also, here was a couple more questions:

On the balancing connector, it has three wires. Two black, and one red. now, is each of the black wires go to a separate cell? If so, then why am I reading 8 volts on that one cell, where if that was true, the battery would have detonated by now? This is all confusing!!! But, the battery pack is in an airtight ammo box in the middle of an empty garage, just incase my questions were right. thanks, Joe

I have a feeling you are measuring the wrong way...
You have the black cable from the multimeter at ground for the first cell and measures 4Volt on the second black wire. Then you move the red multimeter-cable to the red wire and measure 8Volt, which for sure is the total voltage of cell 1 and 2. Indicating both cells are at 4 volt and everything is OK.

I suppose (but might be wrong!!!) that the first black wire is ground on cell 1, the second black wire is + on cell 1 and ground on cell 2. The red wire is + on cell 2.

Alright, I just tested what jooNorway said, and so both cells are at a safe 4 volts. Now, that must mean that there is either a bad connection, or my equinox balancer crapped out. So, I'll probably be going to the lhs today, and test some lipos there. Thanks for all your help, Joe