Surefire e2e head on LX2 body... with pics

[EspionageStudio.Com]

I was playing around last night swapping parts just for fun. I found that for me, the e2e head is awesome on the LX2 body. Low is ultra low, the filament barely lights up at all. Then on high it acts as a normal e2e. My question is, is it hard on the filament, or the batteries to run at such a low voltage? And I'm assuming the LX2 head in direct drive on the E2E body (if that is what it is doing) will be ok too? I have a good time swapping parts now and then, but I don't want to mess anything up

 

[bstrickler]

http://lmgtfy.com/?q=underdriving+incandescent

 

[EspionageStudio.Com]

haha! bstrickler, you zinged me. Love your link 🙂 I'm a hard core googler, I have Google on my phone, my tablet and on 3 monitors in front of me. Heck I can even have my gf google stuff on her phone from across the room, I just didn't think of the correct terminology "under driving" Thanks for the help boss.

 

[archimedes]

Not only is it not good to underdrive the lamp, I think I saw a similar thread recently where someone didn't realize that the light had been left on (ultralow through the resistor) ... then mismatched cells plus lots of current resulted in reversal (boom)

Unless you really know what you are doing with voltage, current, and so forth, best not to "mix-n-match" and wonder what will happen .... Lithium batteries pack a whole lotta energy into a small space.

Important safety tip - just because something "fits" does not mean it is safe.

EDIT - found the thread, here ...

http://www.candlepowerforums.com/vb/showthread.php?t=140598

 

[Illum]

LED drivers probably was never designed to drive something with such high impedance... I wonder what the chip is thinking when the feedback pin is sending this erratic information. Battery hazards aside, I think the driver is going to be short lived

 

[bstrickler]

haha! bstrickler, you zinged me. Love your link 🙂 I'm a hard core googler, I have Google on my phone, my tablet and on 3 monitors in front of me. Heck I can even have my gf google stuff on her phone from across the room, I just didn't think of the correct terminology "under driving" Thanks for the help boss.

"underdriving" is what came to mind, when people like to talk about overdriving bulbs (pushing them beyond their technical limit, to get more power out of them).

LMGTFY is such a useful website, because it's helped me teach people to search for things before they ask, although in your case, it was a helpful question.

I'm just surprised nobody has done any long term tests for underdriving bulbs, since that's a very common question people ask about the P60 and 17670/18650. I think I may have to do that test myself, and see what happens. Worst case, it goes *poof* after a few hours, or best case, does nothing. I have a battery charger that lets me set the voltage, so I think I'll try that tonight or tomorrow.

LED drivers probably was never designed to drive something with such high impedance... I wonder what the chip is thinking when the feedback pin is sending this erratic information. Battery hazards aside, I think the driver is going to be short lived

At least it's a Surefire, so if it craps, he just sends it in to them, and tells them it wouldn't turn on.

 

[Chrontius]

I like this build, and while I understand it may strain the driver, this is the sort of regulated incandescent we really need more of these days.

And really low low settings. Those too.

 

[It01Firefox]

I don't have my LX2 with me right now so I can't check, but afaik the driver is in the head and not the battery tube like on the L2. So the config the OP is running just uses the resistor in the tailcap to get the lower output and it's not regulated in any way.

 

[bstrickler]

Found more info on underdriving for you:

http://www.candlepowerforums.com/vb...61-bulb-blow&p=3181057&viewfull=1#post3181057

A good description of what underdriving does, and how it's bad for the filament. I'd been searching for good info like that for a while now, and stumbled on it by accident.

 

[EspionageStudio.Com]

Thanks for all the help. I have since taken it apart and put it back to normal configurations on both... and in true CPF fashion have ordered an old school L4 and an old 30 lumen single mode e1L to do some lego action on those.