The Eugene Prop Spinners club flying sessions are on Thursdays. The first July session fell on the Fourth. It turned out that fate had decided for me to have my fireworks first thing in the morning.

I was planning to fly a model given to me by Dan Armstrong who had been flying it with a SuperTigre C35. Since I didn’t have one when he gave me the model, I had mounted a Fox Rocket .35 in it. As I was removing the engine, I remembered that my Lithium Ion starting battery had gone dead the previous week. My starting battery is kept in the bottom of my pit box, and I set out to charge it as I had always done, leaving it there but putting the pit box on protective pads on my bench just in case.

After removing the Rocket from the nose of the model I went off to the farthest end of the house to locate the SuperTigre C35 I had recently traded Dave La Fever for.   I was still scrounging when my wife, Carole, hollered, “Is there supposed to be smoke in the garage?”


I ran to the garage to find not only my pit box but also the wastebasket on the other side of the aisle both fully engulfed in flame.  Fortunately, there was a fully charged water hose on a hose reel just outside the back door to the garage. I grabbed the hose and quickly doused the flames. There was no real damage to the bench or the house. The pit box and everything in it were destroyed as was the wastebasket. And there was now water and black residue everywhere.
 
While all of this had been made much worse by leaving the battery pack in the pit box to charge it, it would have still been a disaster had the battery pack been charged by itself as at least one of the cells had literally exploded and there was no sign of the other cell. I have been using rechargeable LiPo and LiIon cells for many years with no problems and had become rather cavalier about the process. Please take the advice of myself and many others. Take charging these batteries seriously. Be sure to take every possible precaution as a mundane process can turn into a major disaster in a heartbeat.

Some tips about lithium batteries and charging from the Flying Lines workshop:

If you don't have it already, you can purchase an inexpensive battery tester that will quickly show you if the battery you are about to charge is suspect and possibly dangerous. At right is one example from Tower Hobbies that costs $25.

Here are some of the signs that a lithium battery may be failing and/or hazardous:

• The battery puffs up to a larger size than it started out.
• The battery has a very short charge life — the flight ends prematurely, for example.
• The battery "dies" suddenly. Lithium batteries tend to peter out, not completely stop working suddenly.
• The battery has been dropped, shorted or otherwise subject to trauma. Damage may not be visible.
• Your smart charger shows an error message when you hook up the battery.
• Your tester shows that not all the cells produce the same voltage or overall capacity is down; the tester may show other problems, too.

If there's ever a doubt, use your tester to check the battery.  If no problem is indicated but you are still suspicious, take your charger out to the patio and use it away from anything that could be damaged by fire.

Safe charging: The battery and charger should be on a fireproof surface and if possible covered by something that won't burn. You can buy an inexpensive charging bag from Tower. Or you can go to your local garden store and buy a very large clay flower pot and a clay flower pot base, and put your charger inside the base with the pot as a lid.

Happy flying — without unintended fireworks!

Remains moved outside show the extent of the damage.