Updated! Scroll to end of entry.
Today I installed six unused Tenergy CR123A lithium batteries into my Surefire M6 Guardian flashlight. The batteries were about 4 years old, but fresh out of the plastic wrap. They are supposed to last 10 years but ones I had used recently had died very quickly. So I wanted to test a batch to see if they were retaining their “juice”, because I have another 50 or so about the same age (I keep them for power-out emergencies as well as regular flashlight usage).
So I installed six of them into my Surefire M6 Guardian flashlight, looking to see how long they would “burn”. After about 20 minutes or runtime: BOOM!
The rear tailcap blew out violently with a whoosh of white smoke into my office. I was sitting a few feet away, and was very lucky— I was not hit by anything. I grabbed the body of the flashlight (almost too hot to touch), and I threw it outside onto the concrete.
Over the next several minutes, it exploded violently at least twice more. The rear tailcap blew a massive burst of white “steam” (nasty stuff no doubt), and the front lens and bulb blew out so completely that I don’t even know where the shards of glass ended up. That area still reeks, even after being hosed down.
I spent the next few hours trying to eliminate the stink from the entire house, from just the original explosion. It really stinks, and I got a trace of it onto my hand, which worries me: my hand stinks of it, and no amount of soap will change that. I don’t know what I absorbed, or what I might have inhaled.
I’ve used dozens of these batteries before in my smaller flashlights, but in the Surefire M6 Guardian there are six of them drawing a lot of power (rating is for 20 minutes at 500 lumens). This is apparently enough to explode them— extremely dangerous. My remaining Tenergy batteries will be going to the hazmat disposal facility in San Mateo county. The body shell of the robust Surefire M6 Guardian was unaffected, but all working parts and end caps were obliterated. I am now short a very expensive flashlight, but I am glad to be uninjured.
Tenergy is made in China— maybe at the fireworks factory? I should have stuck to the good 'old red Surefire batteries, mine say Made in USA.
Total destruction of internal parts and front/rear of the Surefire M1 Guardian. These batteries made it into a godamn pipe bomb. Shown below is where the lens and bulb used to be.
Update June 30! I've gotten some great technical feedback, here in a nutshell are things to be concerned about, from Ron L. Rathbone of Rathbone Engineering.
Like I explained to the automotive guys, for 21 years I have dissected different chemical battery cells and packs from new battery cells and dead battery packs and tested both worn out packs and new packs and cells. From actual users of the batteries I had been able to secure history on the batteries from how often they were used to the range of abuse and endurance and many other factors. Who manufactured the cell, who assembled the cells into packs, their design strategy, good or bad, and a host of other important factors on thousands of batteries and cells in 21 years.
- Age of cell: possible leakage = not a great idea to use older batteries eg so much for 10 year shelf life.
- Water and lithium of any variation do not mix at all. With even a microscopic leakage point and water entered, have fun. [Mine were nowhere near water]
- Extreme heat or cold — all battery cells they have operable temperature ranges. In my case, the power draw did build up extreme heat, which probably precipitated the explosion.
- Long term discharge? Possible heat build up and overload. (My Tenergy batteries had shown signs of premature power loss, which is why I was testing them. Bad Idea!)
- Is the cell manufactured in China by a Chinese factory with Chinese
management? “I do not do Chinese battery cells no matter the label on the cells.”