[Noin]

I wanted to post that separately to get it up right away, now I will go into an explanation of what you did wrong.

First off, you may not have done anything wrong. You may have just gotten a bad cell in your pack. But, if that is not the case then it is likely that you discharged the pack faster than you were supposed to. Each battery type has a discharge rating and if you exceed that you can damage the pack. Lipos cells are very sensitive to this discharge rating, you can't push them beyond the specified limits or you will get the results you have witnessed. In order to know how fast you discharged the pack you would need to have a watt meter of some kind to determine the amount of watts you were discharging the battery at. It should say in your instructions that came with the battery what the safe discharge rating is for that pack. I will give you an example of how this works:

Discharge 10C
Charge 1C

C = capacity of your battery, also known as the mah. In your case 1500.

Keep in mind that 1000mah is equal to 1amp.

So this would be an example equation:

Discharge 10C=10 x 1500 = 15amps
Charge 1C=1 x 1500 = 1.5amps

In this example, if a motor setup that was connected to this battery pack was drawing/discharging the battery at more than 15amps it would damage the pack.

Keep in mind that lipos are not safe when pushed beyond their limits. When used within the specified limits they are quite safe. I suggest you take this pack outside of your house immediately and leave it out there for a few hours to see if it is going to burst. If it bursts inside your house it could cause serious damage to your property.

You need to find someone with a watt meter to measure your motor setup and find out what it is drawing. A word of note, your motors are designed for 7.2V and will not last long at 11.1V. Use the throttle sparingly.

Hope this helps. Any other questions feel free to fire away.