Jason, I’m really grateful that you check up on these things real quick and get back to us. I like LEDs so I get into this more than other things; so that’s why I question this more than usual.

“"Burn time is the total time that the headlamp produces a minimum of 0.25 lux at 2 meters. 0.25 lux is about the equivalent of a full moon on a clear night. Regulated burn time is less than overall burn time."”

I think this is a useless spec. In PT’s lingo, ‘regulated burn time’ is much more useful as it gives you a feel how the light will perform. So when it posted a 1 hour burn time on their EOS II website (as of yesterday), that might be more believable. However, other users have noticed a 2+ hour run time to 50% light (I call it ‘run’ instead of ‘burn’).

“Personally, I would like to see an unbiased test on the Fenix…”

There are. It appears Fenix may be brighter than they claim.
An old Fenix L0D is found here: https://www.fenix-store.com/product_info.php?cPath=48&products_id=405
A lumen and runtime measurement OF THAT LIGHT is found here: http://www.candlepowerforums.com/vb/showthread.php?t=152223

Since then, Fenix replaced their LED with the ‘Cree 7090 XR-E’ (Q4 grouping) which is 25% brighter. ( http://www.cree.com/products/pdf/XLamp7090XR-E.pdf )

“I also find it hard to believe that this light, using 1AAA battery, is putting out 75 lumens, especially for an hour! If you were to ask the Princeton Tec guys, they would definitely call your bluff!”

But it’s true as explained above. That LED only needs 350mA for 107 lumens (and less for the 75 lumens). After a step up converter, the battery probably draws ~760mA (assuming 75% efficiency).

“They are also using much more wattage than the 1.5W that a single AAA battery can produce.”

I assume ‘They’ is Fenix. Let’s see. A lithium AAA is rated at 1300mA. So 1.5x1.3= 1.95W (a battery can deliver). I believe a lithium AAA can keep that up for an hour. But it’s not really that bad. The LED is drawing 262mA (for 75 lumens) x 3.3V (across LED) = 860mW. Assume a 75% efficient Fenix step up converter and we’re drainig 866/0.75= 1.15W from the battery. Even a 900mA NiMh should keep up with this for an hour.


It’s hard to beat a Fenix <img src="/forums/images/graemlins/cool.gif" alt="" />.


-Barry