Strange problem with Nitecore Tube light (stays on/can't turn off)


I put one of the Tube lights on a bunch of our keychains, and today, someone noticed that something was lit in my wife’s jacket pockets. She pulled out her keychain and the Tube light was on, apparently in HIGH mode. The light was kind of hot.

Anyway, I figured that she had inadverdently turn it on, but when I tried to turn it off, it would not go off.

I told her to take the light off of her keychain before we drove back home, because I was worried that it’d drain the battery and maybe explode or go into flame. I assumed that somethng was shorted, and was planning to take it apart when we got back, but then on the drive back, about 10-15 minutes later, the light went off.

I then pressed the button and the light was working “normally”, i.e., it had low and high mode and variable mode also was working.

I’m probably going to just trash the light, but was wondering if anyone has noticed this behavior with their Tube light?

Is this some kind of defect where if it is turned on in HIGH mode and is kept on too long that it gets stuck in HIGH and won’t turn off?

The battery is protected, so there should be no danger.

Very strange behavior, though.

Ok, thanks. Do you think it’s safe to keep it/just recharge it, or is this a defective unit? I guess for myself, I’m more inclined to dump it :(…

I remember testing the Tube when I first got it. I left it on high mode for a full battery charge without any strange behavior. It got a bit warm, but not hot at all…

I would recharge it and try to force the behavior you experienced.

Ok, I’ll try that and will post back on this thread either way…

I would check switch first.

The switch works NOW, but it definitely wan’t working at the time I mentioned. That is (one of) the weird thing!

Check to be sure there are no metal parts in the tailcap (other than the contact itself) that can contact the battery. I once had to cut a ring out of packing tape to prevent contact.

Maybe the button was compressed so long, it took a bit to "spring" back out?

I really love those tubes. I do find that mine accidentally turns on sometimes. Wish it didn't do that. Thought about sanding it down, but then it would be harder to find the switch in the dark.

The “Tube” lights have plastic bodies, no tailcaps :)…

When it was stuck on, I pressed the button all kinds of ways. It didn’t feel like the button was physically “stuck”. Also, when it turned off, it just turned off by itself and I wasn’t touching the button at that time. After that, the button could turn the light on “normally” including high, low and variable modes.

Still charging….

Well, it’s charged now and seems to still be working “normally”. My wife doesn’t want it on her keychain anymore though, so I’ll probably just keep it around but not on a keychain or in a pocket. Weird…

Funny, I had the same thing happen with an X6 (with a short tube and small cell) just last week.
It was on (at the lowest level) overnight; when I picked it up in the morning it would not shut off — no number of clicks would make the LED quit shining, and even a very brief loosening of the head til the emitter went out didn’t make the switch behave again, when I retightened the head after a second or so the light stayed on again until I pulled the battery for a bit. That reset it to normal.

Perhaps they’ve started using a different kind of phlogiston or different class of fire demon in these things recently.

I have also had this happen with a tube. I just let the light go until the battery died, recharged it and everything works fine. Haven’t had a problem since.

ohaya, if you plan to dump it, no harm in opening it up and taking a look inside. Is it possible that it got wet from wet hands and an open charging port?


Ok, this is an older thread, but this same problem (tube light turned on high and won’t turn off) happened again, with a 2nd one. It wasn’t wet, I had just taken the keychain off of the hook in the house and put the key into the car and noticed the light was on high. Pressing the button wouldn’t turn it off.

As I said, this is the 2nd/different unit. I took the one that had the first problem off of the keychain and it’s been sitting on my desk since way back when.

This other one was on another keychain and the switch/button was definitely clicking. I was on my way to work otherwise I might’ve tried to open it up at the time but couldn’t because of time.

My wife left it until it turned off by itself and it’s working again now, but off of the chain.


Same thing happened to one of mine yesterday. Once it had run itself down I recharged it and its now working normally again.

it could be that the tube got so warm and the circuitry gone haywire but when cooled down it’ll go back to normal.

i do not own a nitecore tube but I’ve ran too many lights hot and usually things go weird when it gets hot (like modes don’t change or stay high, etc…)

give your tube a chance and it might go back to normal