L2D Q5 Overheats - How long is normal?

Hey Guys,

So I have a L2D Q5 that I love and use quite frequently...

When I first bought it and used it, the Turbo mode would never cause it to overheat and expand the tail button.

However, in the last 2 months... everytime I use the Turbo it (for over 20 secs ) the tail cap starts expanding and I fear it will overheat.

Could someone tell me if the length of time I can run it on Turbo (safely) should be getting shorter and shorter the longer I own the light? It seems like the problem has gotten worse lately. Any solutions besides just not using the Turbo?

Thanks everyone.

So it gets hot enough to expand the trapped air inside the light... and increase internal pressure enough to push out the rubber switch cap?

Thats very odd. what type of batteries are you using?

Yep, the air inside heats and expands the rubber cap in under 30 seconds.

I'm using Eneloops AAs.

I know this is a commonality amongst the L2D cause of the lack of heatsinking but mine seems to overheat REALLY quickly.

Whoa... that doesn't sound too good. Can you tell us more about the batteries? Are you using something different than when you first got it?

+1, we can't be of much help if we don't know what batteries you are using. Also have you changed the types of batteries you have used? Not sure if it matters with akalines, but could using a partially used cell and a fresh cell cause this to happen?

Hmmm... I use Eneloops in my NiteCore and when on high mode it does get warm, but not so hot that it starts to make it uncomfortable. Let us know what you find out.

I've been using the same batteries since I received the light (Eneloops)

My main concern is that I used to use Turbo for at least 5+ min with no adverse effects and now I can hardly use it at all.

Edit: The batteries are always paired (in use & when charging) and I haven't switched the pairs up at all.

You could always remove an 0-ring.

I'd actually be happy with this because it would indicate that my flashlight would be quite waterproof if even a bit of expanding air cannot escape.

I'm going to check mine tonight when I get home and see if mine does the same thing. I've never noticed it before.

Sounds like the batteries are venting. The air in the light isn't getting hot enough to expand the rubber in the tail cap in 20 seconds.

Mine has never overheated or anything even after using it for a while on turbo, just gets very warm. Try using regular alkalines and see it it does it. Your eneloops might have possibly vented or something.

fleetparadox said:

Could someone tell me if the length of time I can run it on Turbo (safely) should be getting shorter and shorter the longer I own the light? It seems like the problem has gotten worse lately. Any solutions besides just not using the Turbo?

Click to expand...

I have been using my L2D as a bike light, where it runs on turbo for 30 minutes at a time. This has never given any problems.

Like everybody else I would suspect your batteries, do your have another set your can try in the flashlight?

when i got mine i tested to see how long before it overheats and dims..i run mine on E2 lithiums and they dim by by 13 minutes..however if on a bike ride they are cooled but just doing tailstand it builds heat obviously

i think a solution is a needle prick in the tailcap, though you might lose waterproofing BUT my theory is that the pin hole is so small that the rubber will act as a seal but when gas builds from battery the pressure forces it out and for waterproofing if you drop in the puddle chances are there will be not enough depth pressure unless your 10 feet under water for water to force in the tailcap

It's definitely not a problem with the light, you have a battery venting.

Curious.... can you measure the current draw? Eneloops are supposed to be very durable, and able to keep up with some heavy current demands. Hence their popularity.

Fenix states 10 minutes, which I beleive is fairly conservative. I haven't used turbo much, but even after 5 minutes I don't notice any heat buildup. Something's wrong here, but I'm not enough of an expert to say what.

There is NO way that the tailcap is balooning because of thermal expansion of the air inside.

(The amount of free airspace in the carrier is quite minimal. Even more if you consider that there is a temperatuer gradient along the light. A significant change in form of switch suggests that the batteries are the culprit.)

IMSabbel said:

There is NO way that the tailcap is balooning because of thermal expansion of the air inside.

(The amount of free airspace in the carrier is quite minimal. Even more if you consider that there is a temperatuer gradient along the light. A significant change in form of switch suggests that the batteries are the culprit.)

Click to expand...

Agreed. It would have to get extremely hot before you would notice the tailcap balooning out from heat alone.

You obviously have a battery that is venting. I have run my L2D Q5 on turbo for hours on end, without it getting especially hot as long as I hold it. I forgot about it one time and it was tailstanding in turbo for over 1 hour. When i found it, it was very hot, almost too hot to touch, but still, no balooning, and it still works fine. It's just no way it can heat up in a few seconds.

Stereodude said:

Sounds like the batteries are venting. The air in the light isn't getting hot enough to expand the rubber in the tail cap in 20 seconds.

Click to expand...

One solution is to prick the Tail cap rubber boot with a fine pin,
it will allow the gas to escape

TORCH_BOY said:

One solution is to prick the Tail cap rubber boot with a fine pin,
it will allow the gas to escape

Click to expand...

That doesn't solve the issue of having a dud cell. You shouldn't keep using a cell which is venting.