Surefire L2 1.5 amps on High

cmacclel

Flashlight Enthusiast
Joined
Jul 15, 2003
Messages
5,018
Location
Sweden
I was telling a friend that owns a L2 that the light was made to run on low with only a couple minutes of high at a time. We checked the amperage draw and with a used set of battery's was 1.5+ amps! WOW I guess thats why it gets hot after even 1-2 minutes on High. If this light was left with a fresh set of batteries there's a good change damage would occur!


Mac
 

JasonC8301

Flashlight Enthusiast
Joined
Nov 13, 2001
Messages
1,218
Location
NYC
I get 1.4-1.5 amps on high for the L2.

Serious damage will not happen because after a certain point, the light drops down and goes up and down like a roller coaster (thermal management.)

The LED life will be reduced in life if left on high all the time though (contiuous on high running through multiple sets of batteries at a time.) Surefire has improved upon the L2 by making it have a bigger heatsink.

Yep Mac, it can get REALLY hot if left on high for 30+ minutes.
 

cy

Flashaholic
Joined
Dec 20, 2003
Messages
8,186
Location
USA
1.5amps draw at cell doesnot always mean 1.5amp across luxeon.
 

cmacclel

Flashlight Enthusiast
Joined
Jul 15, 2003
Messages
5,018
Location
Sweden
cy said:
1.5amps draw at cell doesnot always mean 1.5amp across luxeon.

It should be pretty darn close or the driver board would be super inefficient and would make the light even hotter.


Thanks Jason I had no idea the L2 has thermal management.


Mac
 

Ray_of_Light

Flashlight Enthusiast
Joined
May 11, 2003
Messages
1,147
Location
West Midlands, U.K.
My L2s draws 1.4 Amps from two new SF cells.

On high, the L2 gets even hotter than the L4. The L4 draws 1.0 Amp at 6 V.

I don't think the L2 LED will get damaged by this temperature increase, since as said, there is a thermal limiter as you can verify leaving the light on in a sink full of water, while pointing the beam to the luxmeter.

Anthony
 

TORCH_BOY

Flashlight Enthusiast
Joined
Jan 25, 2004
Messages
4,242
Location
Australia, Vic
Re: Surefire L2 1.5 amps on High
Thats 9 watts of power being dissipated
5 watts to the Led and 4 watts in losses
 

wasBlinded

Flashlight Enthusiast
Joined
Dec 14, 2004
Messages
1,222
Location
Oklahoma
Under a 1.5 amp load, the lithium cells will not be delivering 6 volts. I don't know what they would measure at, a SWAG would be 5.4 - maybe more maybe less.


Perhaps too they are driving that LuxV at something over 700 mA - has anyone actually measured?
 

photo2000a

Newly Enlightened
Joined
Jan 25, 2005
Messages
138
Location
ny
so if the l2 is ment for mostly low power use, which sf @5w is ok for always on 'high' w/o issues??

i have a l2 and use mostly high don't wanna fry it, hey what an excuse for another sf hmmm but which??
 

wasBlinded

Flashlight Enthusiast
Joined
Dec 14, 2004
Messages
1,222
Location
Oklahoma
The larger lights, like the U2, L5, and L6 all have greater thermal mass and radiative surface area, so will handle waste heat during prolonged runs better than the L2. It largely boils down to size. Thats a pun I think.
 

Luna

Enlightened
Joined
Dec 27, 2004
Messages
874
Re 1.5Amps

Remember you can measure the current and the voltage directly on this light since the electronics are in the body. I cannot recall the exact measure ments but a while back I measured some pretty stout numbers going to the head.


photo2000a said:
so if the l2 is ment for mostly low power use, which sf @5w is ok for always on 'high' w/o issues??

i have a l2 and use mostly high don't wanna fry it, hey what an excuse for another sf hmmm but which??


I finally picked up a E1L Outdoorsman yesterday. It holds the RCR123 that my L2 will not (plus it is probably closer to the E2L spec with the ~4.2v). I think I'm really gonna like this light.
 

Latest posts

Top