copied with permission: We have a Cozy MKIV in the shop that I am working on the wiring. The builder installed a Lithium Iron battery. Yesterday, I heard a soft poof and then a hiss coming from the battery, and within ten seconds the battery was spewing a huge smoke plume and was melting the battery's case. We scrambled to get the hanger door open and the plane pushed outside. While the smoke decreased after about 3 minutes the heat continued. I decided I could get in the back of the plane and cut the battery cables with a good set of cable cutters. So, I held my breath and climbed in and as quickly as I could I cut the cables and tossed the battery out on the ground. It was then I was able to get a video of the battery as it continued to self destruct. The battery burned for at least ten minutes before it quit spewing smoke, sparks and its internal parts. We have just finished installing a pair of these batteries in a Long-EZ and within a few days of installation one began showing signs of not holding a charge and I noticed it was getting warm to the touch. I removed it and Aircraft Spruce promptly warranted the battery and sent us a new one. The one that burned yesterday was showing similar signs of not holding a charge and about an hour before it burned I noticed it was warm to the touch. I had no idea at the time of the first battery failure how close it was to the catastrophic results that we saw yesterday. It is absolutely horrifying to think of that happening while airborne. As fast as it escalated it would have filled the cockpit with that terrible smoke and fumes in just a couple seconds. By the time I took the video linked below the smoke had tapered off considerably. In my opinion no one in the aircraft would have survived had this happened while in the air. No one should even consider having these batteries in the aircraft with them. One of the scariest things I have seen. Might as well have a wing come off, the outcome is the same. I have added a link below to the video I took. Have a look at the video, you'll be shocked. ” Follow-up: “I have had a conversation with (the battery manufacturer). He seems cordial, honest and sincere. He had been briefed on my recent experience with his batteries and was aware of my opinion. Frankly, he said nothing to change my mind. He says the most likely cause of the fire is overcharging of the battery. I accept that. But, he says it could also be caused by completely discharging the battery and then trying to charge it. Says if you completely discharge it such as leaving the master on even once, the battery is ruined and you might as well throw it away. He told me he was aware of two fires occurring while in flight. Both he says were caused by the on board charging systems. Both fires were in Kitfox aircraft with Rotax engines and charging systems. Both times the pilot was able to make an emergency off field landing and no one got hurt. Both batteries were mounted on the engine side of the firewall. He told me that he designed a system for maintaining the batteries installed by a prominent kit manufacturer. He says that they mounted them in the engine compartment and installed a fireproof case around the battery that would vent the smoke overboard in the event of a runaway. He told me he knew that the batteries were a "smoke bomb" when they burned. He says he makes a special charger for the batteries but, he also says it is not required.