Discussion: Headlamp Battery Fire

Caution when charging LiPo batteries:

Many headlamps use Li-Po (Lithium Polymer) batteries, the same ones in an iPhone etc.
These are the flat rectangular packs, used in many lights including Ay-up. The ones that have cylindrical batteries are Li-ion.

Recently, a friend was charging his LiPo battery from Batteryspace with their approved charger overnight when the smoke detector went off. He ran downstairs to find it on fire! Luckily nobody was hurt, but there was some damage to the house and several nearby batteries. This was the battery many folks got with the Night Lightning kits years ago.

I had a dental colleague who found his very expensive Loupe light battery pack on fire in his lab.

I read of a case where an Ay-up pack caught fire as well.

These are rare, and apparently happen if the battery is punctured, shorted or overcharged by a malfunctioning charger.

I believe Li-ion packs can also burn, but these are rarer. They are used in laptop computers as well as bike lights. I build battery packs with protection circuits that should not overcharge, but I suppose anything is possible.

If you're bored: http://batteryuniversity.com/learn/article/safety_...

Standard instructions for charging these lights always say "do not charge unattended, charge on non-flamable surface such as concrete."
Many folks with high power LiPo for radio controlled drones and cars use a special LiPo-save charging bag:

http://www.amazon.com/Battery-Fireproof-Storage-Ma...

My advice for anyone charging LiPo and Li-ion batteries for headlamps:

Charge and store them in a metal cookie tin, or preferably a special LiPo-safe charging bag. Ideally placed in a metal sink, tile or concrete floor or granite countertop when charging. Don't have them charging when you leave the house.

I have bought 10 bags for folks with Bentblasters. I'll bring them to races etc.

@'Bent thanks for posting!

Some additional recommendations for storage:

If storing your batteries in a metal cookie tin, make sure you insulate the tin with 5 or so layers of duct tape electrical tape, etc. You don't want to short your batteries in the metal container as it will cause the container to quick heat up! Rare to happen, but could especially if there are nicks in the protective warping of the battery.

A ceramic or glass pot/container would be better - transmits heat at a slower level than metal, is non-conductive plus is fire proof.

Good point about metal tins potentially shorting batteries. Our battery packs are encased with recessed contacts in plugs and double armoured so they can't short, but if you have open batteries with exposed contacts be sure they are protected inside the container. Insulating the container makes good sense.

I always travel with batteries in a cookie tin, but a big ceramic container with a lid would be excellent.

My light runs on 18650 batteries, which do have the exposed ends. As I read your great post, I was looking at my batteries, as they were charging. I remembered that I shorted the battery a bit when I was unpacking it. The positive terminals are surrounded insulation and the negative terminal. The negative terminal runs the whole length of the battery and is used for the main casing of the battery..

When I get bare cells, I store them in the plastic case they ship in, inside something non-flammable like a tin.