new details at fasttech about 7 led FandyFire

fasttech has just posted new details about this light….
they say 3500 mA at tailcap…

so i am asking : for 7 leds, does this mean .50 amps per led ???
and then how many amps can you give 7 leds , generally, a ballpark figure
before it gets too hot too quickly….

Whoa! SIX 18650s???

That's 3.5A with two cells, so 3.5A x 2 = 7.0A. Now divide 7.0A by 7 LED's and get roughly 1A per LED.


you can’t really ball park, some hosts will take 3a/emitter, some wont, I guess the linked light will give awesome run times but wont be so bright, considering the number of emitters in the array.

Personally, i’d see the numbers as pretty low, but given how cheap the light is, I could possibly live with it, I just dont see the need for so many emitters, I’ve got a build on at the moment ( thanks chi x), it has 3 xm-l u2’s, is about the diameter and length of a 1d maglite tube and should give about 3000 lumens on turbo, I find this more interesting tbh.

i take it those 18650s are 3s 2p?

this could potentially be a runtime HOG if the driver is efficient enough

I think there is a limit on the size you can go down to, ie you need plenty of mass to deal with all the heat, but it is possible to have a wow light, there are 3a/emitter 7 led drivers, but I would see them as low hi turbo rather than low mid hi because they will over heat.

The same solarstorm labeled light has already been tested by a forum member here:

Until youve played with one, you might want to think again. The darth is a very well crafted, trimmed down compact little flood monster. Doesnt feel at all like 3 x 18650’s, thanks to no battery carrier and rectangular rounded shape tube. Its driven just hard enough to start getting quite warm in your hands. Not HOT like an SRK.

Play with the darth outside and not indoors and I think you’ll be quite impressed with it in its stock form. IMO, there’s to many people trying to impress their lumen meters with mods rather than what is useful in actual use. But then, my lights are nearly always on continuously for more then 15 minutes at a time; where heat becomes a major concern.

ok, fasttech’s is fandyfire, not solarstorm, so I’ve been wondering about the driver, and hoping for this information.

here are my drunken calculations

3s2p battery is ~11.4V under load when fully charged

3.5A at tail is ~40Watts into driver

80% efficiency

32 watts - divided by 7 emitters - 4.6W/emitter

with those guesses/assumptions, plus another for reflector and lens losses, we’re a bit under 3k lumen

but the REAL question is if the driver is the same as in the solarstorm, since there is a resistor mod that was well tested on another forum (and linked in the solarstorm L3 thread here)

It's because the cells are running 2S3P (pretty sure). That's 8.4v and the LED's run on +/- 3.7v. General rule of thumb is to double the amp reading (when your tailcap reading is on 2 cells in series) then for a multi-LED light divide that by the number of LEDs.


this, +lots, its one of the reasons I love my mtg-2 torchlite, comfortably around 2000 lumen from a single emitter and a nice floody beam in a 2d maglite sized host with no heat sinking issues. Some may not be impressed with it but I love it to bits.

I own all 3, the L3, Darth and SRK (xml u2 SRK). The L3 has the most flood and the SRK a slightly more defined hotspot but they are close beam patterns. The Darth also has a similar beam pattern that is closer to the L3. The only thing the Darth has going for it is that I can fit it in most pockets. If you have tight jeans or a small pocket it wont fit but I’ve had success with medium and bigger pockets whereas the L3 and SRK are to fat to pocket them. The Darth is the brightest light I own that I can put in a pocket and I like the ring switch and secondary tail switch master on/off ensuring it does not turn on accidentally in my pocket! The L3 and SRK are very close beam and brightness wise. I’ve only been out with these 2 at the same time once but I remember beams shots seemed to go the same distance in my tests. The ceiling bounce tests showed the L3 to be brighter according to the lux meter. The SRK scored 62 lux and the L3 83 lux. The lights were 8 feet from the meter pointing to a white ceiling from the floor. Both tail stand and light a room well. The other advantage of the L3 versus the SRK is the ability to be variable dimmed. I was able to calibrate the L3 to approx 1000 lumen output and since each of the LEDs are not working very hard the heat was only warm and it will run for 11 hours straight with that output and you can handle the light without buring. That’s rather useful. I have not tried a long run test with the SRK on low mode but in comparing to the Nitecore ea4 860lm and a a few other 1000lm lights I would think the output of the SRK is only around 600lm on low mode. Another thing to note is the L3 will run on high mode for 20 minutes before the heat is becoming uncomfortable to touch where as the SRK is the same hot heat after only 6 minutes or so. I guess this is due to the L3 having 7 under driven LEDs whereas the SRK is driving the 3 LED’s much harder making more heat maybe. I much prefer the SRK button and modes over all 3 of these lights. Its easy and practical when out in the field. the SRK will cycle through the modes as fast as I can press the button where as the L3 has a delay of a second or more and the damn 3000lm of SOS flash every time I cycle through the modes! My favorite is still the SRK out of this group. Small and bright with easy UI and cheaper than the L3. However the L3 has cool features and I am glad I own it, loving the battery indicators as you can see the batteries were low in this pic below! I uses the variable light to take this picture! lol