MN01 is 20Lm at 3V and draws 1.06A (<-- my educated guess at current based on runtime and capacity of CR123A, but may have as little as 0.9A draw). CR123A voltage, however, will sag to about 2.55V under a load of 1A, so it's really only a 3V lamp
nominally. Because of that, it drives nicely on two NiMH 1.2V, but two fresh alkaline may flash it, and two Energizer Lithium definitely will. MN01 will immediately flash on one 3.7V liion or 3.2V LiFePO4.
MN03 is 60Lm at 6V and draws 1.08A, but, again, CR123A voltage sag means it's really about a 5V lamp, which means it will safely drive quite nicely, though be slightly under-driven, on one liion for maybe 50Lm.
MN03 is 25Lm at 6V and draws 0.51A, though CR123A voltage sag means it's a little over a 5V lamp, 5.2V, 5.4V, somewhere in there. It will also safely under-drive nicely on one liion for about 18Lm, and on one 3.2V LiFePO4 for maybe about half that brightness or a little more, and amazingly, MN02 will also fire on two NiMH 1.2V for about a lumen, and with 2000mAh cells has a very long runtime of about 4–5 hours. As yet, I have been unable to flash an MN02, but two liion should destroy it.
I remember the threads here about under-driving lamps in 2014—2016, and the explanation is that giving a lamp less voltage will foul or slow the halogen cycle, leaving more soot on the glass, and darkening over time, and shortening the life the lamp.
But I have been under-driving lamps quite a lot, especially MN02 and Tad Customs lamps, but also MN03, and I have not seen this occur, lamp darkening, not in 8 years of doing quite a lot of under-driving, and I have seen no evidence of it whatsoever in any of Surefire's E lamps. In my experience, under-driving lamps merely gives less lumens and lower color temperature, but also
extends the life of the lamp, not shortens it, with no perceivable darkening. Current draw is unaffected, i.e, it doesn't change with lower voltage, practically speaking. Safely overdriven lamps should draw more current as per LuxLuthor's Destructive Incan Bulb Tests, but I haven't been able to detect any reduction in current under-driving E lamps at these relatively low voltages and current.
The only lamps I have seen get dark are some Lamptronix bipin avionics lamps (Maglite Mini and Solitaire sized lamps) I found on eBay years ago, and they got dark when fully driven and overdriven.
Mark at Lumens Factory (closed until 24 April for site upgrade) still sells
E Series lamps designed for liion voltages, apparently now built to order (he told me he does not keep inventory of incan lamps anymore, makes them as the orders come in).
Tad at Tad Customs once sold a handful of lamps for liion voltages (1.2A 3.7V, 1.8A 3.7V, 1.0A 6V and 1.2A 7.4V, among others), but he closed his web shop a couple years ago. With Tad's assistance and blessing, I am working on sourcing those lamps from the manufacturer, but they'll require a socket to be used, as they are bipin lamps. (And if/when successful I'll contact Mister Ed to figure out a way to make them available to other CPF members that want them).
According to fivemega, Streamlight bipin lamps also can be used in E with liion, but they'll also require a socket, but I don't have voltage or current specs on them. fivemega also used to sell a socket for E, as well as a G2 halogen bipin lamp custom made for him by Carley, the 1794, that is 6V (7.4V) and 3A for 1000Lm of lovely halogen. I sure wish we could get more of those. They require a socket and were too long to fit in an Elite head without modification (unscrewing the bezel a little and adding a small ring to move the lens further away), but the modification is non-destructive and fully reversible.
www.lumensfactory.com
