Lithium polymer (LiPo) batteries, with their high energy density and affordable price, have risen to prominence among RC hobbyists. Effectively dethroning nickel-metal hydride, LiPo batteries enable RC vehicles to be lighter and run longer. However, as with all engineering advancements, certain trade-offs had to be made in the R&D phase.

LiPo batteries can, if not handled properly, explode.

This doesn’t happen often, but the very fact that it can should be a warning to every hobbyist. Do your research!

One of the most common ways a LiPo battery can combust is by charging it incorrectly. It is therefore necessary that you supervise your batteries during the entire process. You should also have a bucket of play sand or a fire extinguisher (preferably both) quickly accessible. (N.B. LiPo fires are best put out with sand.)

In the event that your battery does explode, it would be incredibly convenient if it is in some sort of container. That is where fireproof battery bags come into play. You can place them in while charging, and, if it does explode, it should be contained. Please note, however, that the fire could still get out of the bag if there are many cells in the battery. For this reason, I made my own charging station, inspired by a design in a FliteTest video.

This entire station design was about $13. It is simply a cinder block, with a bag of play sand placed over top of the slot where the battery is located. With this placement, if a fire were to occur, the fire would melt through the plastic bag, allowing the sand to fall into the cavity and extinguish the fire.

Even with this seemingly fool-proof design, however, I am still always watching it and have a bucket of sand along with a fire extinguisher within arm’s reach. Never leave your LiPo batteries charging unsupervised.

Additional tips to prevent fires from occurring:

• Always balance charge your batteries
• Use a battery analyzer on your batteries frequently to ensure all cells are at similar voltages (within .02 V max difference)
• Do extensive research on the batteries you plan to buy and also on charging setups (this blog does not count as an authoritative source)
• Inspect your batteries often
• Don’t charge them if they look irregular

Fly safe! Ad caelum!