Over my X-mas break I attempted to put together a remote control plane (1.5 MB image) I intend on using as my first UAV. My first order of business was to get my electronics hooked up correctly and working on the bench and then proceed to the assemble the fuselageand mount it. This is how the "incident" began.

I was working with a friend and we hooked an 10A electronic speed controller (ESC) to the battery, then to the reciever. The engine channel would not respond so I hooked up a servo to another channel and it worked. I repeated with 3 other channels hooking servos to them and they responded. But the engine would not turn. Then I gave it full power and I see smoke. I kill the power. The smoke is coming from the ESC heat shrink wrap and also from the connection to the battery. I stop everything and while trying to get the battery unplugged I notice the wires are hot as shit! It's melting the wires! I still have it connected to the ESC and receiver and I'm trying to get it unhooked as fast as possible knowing the warnings about this type of battery. The battery starts to balloon immediately and I think OH FUCK it's going to explode. Images of the house burning down are very real now. So my friend gets it disconnected with a little pain (hot melting wires remember) then drops it to the floor and moves quickly. I toss a hard hat on it to try and contain whatever might happen. After about 5 minutes of waiting we decide to delicately remove it outside where it can cause the least amount of damage.

The next day I took this picture and did some research. I found a few videos online showing exploding li-po batteries. I find that I was not nearly as careful enough. Take a look at this forum post to show the needed safety precautions when deailing with this type of battery. From now on I will treat it like nitro and keep an eye out for safety concerns.

Upon my research I realized that a few things may have happened to cause this:

1. Discharge rate was too high - ESC might have been on the fritz. I doubt this.
   
2. Voltage dropped below 3.0 volts per cell and made the battery unstable.
3. I dropped the pack that day and did not inspect it. A dropped li-po pack can become unstable by shorting out internally.

So what I plan to do is start fresh with a new brushless engine (The one I'm using was an old can motor brushed 370 from another kit), a new brushless speed controller with programmable low voltage setting, and a nice battery with built in over-discharge detectionand temp guage. I will charge them outside and leave them in a "bunker" made out of a flower pot and lid.

Many people sware against li-pos because of the fire hazard. Many swear by them and claim they are safe with the right precautions. I say this - anytime you store energy you have a potential hazard. Treat them with respect and you will be ok. Treat them with a lack of respect and you may end up homeless.