just been doing some maths on the length of batteries....

yes but i can feel that when the tailcap gets srewed on its that pertruding plunger thats wanting to stop it going all the way home… if i slightly unscrew the extension tube the tail cap goes on all the way so surely if i take a bit off the plunger its going to give me a couple more mm to play with??

Yes, it will that is what I did with my stl-v2.

thats the copy of the m3x right?? does my tailcap look similar to yours??

Yep, here a picture of mine is.

thats exactly what i was going to do… so was yours acting in a similar way and has this 100% fixed the problem??

ady, it could be a comibination of things. First of all if the battery you're using is too long, nothing else is going to help, and if your measurements are correct, they are. Try to get ahold of an 18650 that is actually close to 65mm long. I just ran down to the office and checked the length of a few:

Callie's, Hi-Max, Solarforce: 68.5mm
Trustfire, Xtar: 69mm
Ultrafire: 66mm

In my N-Light ST50, the Trustfire and Xtar will not work - the .5mm makes a difference. All other cells I have work in it. You might find that the battery length and/or removing the tailcap plunger is all you need to fix it. As JMac mentioned, too long and the unanodized portion of the body tube is not seating properly, or the spring is getting crushed.

Yep, it totally fixed the problem. Here the insides of the switch are.

Forgot to mention it but it also works without the brass plunger.

i think im going to take the plunger out first…. if this doesnt work ill have to buy MORE BATTERIES!!! i dont know anyone with any so ill have to get them…. the aw at 67.3mm are the shortest i can find. im really hoping its that plunger as its been bugging me for ages with this thing now!!!

Couldn't you just use unprotected batteries?

yes thats my first move before i start messing with it too much, im hoping this will solve it as its getting silly now lol

Have you tried taking apart the switch yet?

no as the light is up at my girlfriends but im off work friday so ill have all day to mess about with it then…. im actually tempted on going round just to take that plunger out and put my mind at rest!!!

Oh ok. Good luck!

thanks…. if this doesnt solve it ill be gutted, im confident its going to though.

She’ll love that, “oh hi hun, just need to grab my light, have you got any tweezers?……” 8)

I’ve been getting home late, and had to let slip I’m waiting on another light…… I didn’t mention the other two that may show up in the next couple of weeks lol, ignorance is bliss.

It’s too bad we’re not closer, you could have helped yourself to any of my cells to see if they fit. You could also pm torchy the battery boy on here, he’s Glasgow based and has an eBay shop with a fair stock of decent cells. I’m sure he could fix you up with something, I’ve had a few bits off him now and they’ve always come really quick with excellent communication. Worth a try. :bigsmile:

Just to add a couple of data points…
My M3X works well with TrustFire flames (68.5mm each), and Trustfire 3000mAh (68.8mm each)

It does Not work with Intl-Outdoor NCR18650A 3100mAh (68.9mm each).

I really would not have imagined that one tenth of a mm would make any difference, but I think it does. If you’re going to get new batteries, I would keep them under 68.8.

(Not my measurements, but from: http://lygte-info.dk/review/batteries2012/Common18650Summary%20UK.html )

FIXED!!! Thanks for everybodys input on this…… simple fix…… took the plunger out and it works perfect now…… not even going to shave it down…… im now happy!!! :bigsmile:

Nice investigative work Andy. Hopefully I’ll remember this if I ever encounter it too. Good to know you got it all sorted out. I usually have the opposite problem (loose rattle cells and intermittent cell contact) since I only use unprotected cells.

I just realized the easy way to check for this. The tailcap threads are anodized, so the current cuts off if you back it off by unscrewing it a bit.

However, if you unscrew the extension tube from the side closest to the emitter, the light will turn on when the tube has enough room to accommodate the batteries you have used. Those threads are not anodized.

I should have thought of that before. But, if anyone else is having problems with this, it will help you troubleshoot your issue.