Hi there folks, I recently revived a completely dead (un-chargeable) battery pack with a simple process. This is not a guaranteed fix for all packs. I hope it works for you.

What you need:

1. Dead Play & Charge battery pack.
2. Charge cable.
3. Freezer (any type)
4. Xbox 360 Controller
5. Xbox 360 or Preferably a computer with USB slots.

First thing you need to do is place the dead battery pack in the freezer for at least 24 hours. I forgot and left mine in for about 32 hours. Once this amount of time has passed, take it out of the freezer and let it warm to room temp. Then simply hook up the battery pack to your Xbox 360 controller and plug it in to your Xbox 360 or computer. I recommend using USB slots on your PC to prevent your Xbox 360 from running for no reason besides charging. Hopefully your pack will accept the charge. The process can be repeated if no results are shown the first time. Again, this "IS NOT" a fix for all packs. This worked on my Pack the first time I tried and I have now used the pack for several hours and it is holding a normal charge. Good Luck!