hi all, as title said, i looking for a driver to drive 4x xhp70 from a single 21700, that can be fit to a suitable convoy host with head diameter no bigger than 40mm and able to output at least 13000 lumen same as the Imalent MS03
Any idea/suggestion is appreciated, many thanks
Have you done the current calculations? Thought about the heat they will generate in such a small head/ body?
There are 3V XHP70.3 made now- so that simplifies the driver a bit.
yeah ofc it will be hot, so driver need to have temp control, with anduril even better
btw do you know if 3v or 6v led driver will be more efficient fr 3.7v source?
I don’t think you’ll find much in the way of drivers. You’re looking at 15 Amps per XHP70 LED- so up to 60 Amps total!? I doubt you’ll find anything smaller than the drivers made to suit the soda can sized multiple emitter flashlights.
You want a single 21700 doing that?
yeah imalent ms03 and nightwatch a54u doing that so why not
the ampace jp40 can handle more than 60 A IIRC
MS03 only has 3 x XHP70.
yeah but if can then 4 is better than 3 if you want the brightest right?
Cree lists the 3V 70.3 with 14,4A. So 3 would come out to ~45A. Given that the JP40 seems to settle at 3,5V under load and 50% charge. You can have a maximum resistance of 0,5V/45A = ~ 0,1 ohm. I’d guess a fet switched diret drive with a 2nd channel consisting of i.e. one PAM2804 per led to have an efficiant low power mode for up to ~1300lm would be the way to go. An attiny with anduril for the control. Only issue, you’d have to build it yourself, since I don’t know a ready made one, but with kicad and i.e. jlcpcb it should be possible.
Do you think using the 3V or 6V XHP 70 would be more efficient?
Last I checked, 360W (60A) 6v boost driver small enough to fit in a 40mm head doesn’t exist.
It may even be physically impossible from a component standpoint.
so do you mean that the Imalent ms-03 is using 3V XHP 70?
Yes, for the above reason that no boost driver exists.
3V is the way to go, since going 3 or 6 won’t make a difference on the power needed to drive the leds. So with 3v, you get the losses in thae battery, the battery contacts and the fet. While at 6V you’ll get additionally the losses of the bost converter (the coil, second fet or diode).
There are boost converters that use an external fet, whith which you can build one with the needed power (the 360w that gravelmonkey said), but it will just be less efficiant, since since the main losses will be battery + contacs which either way will run at the cell voltage.
Boost /-Buck converter shine here in the lower power modes, but at full current, a fet and 3v will be better.
Another question here is what constitutes a suitable convoy host? Stuffing 4x7070 emitters in a light and finding a proper PCB and optics isn’t trivial. 
You could try to stuff 4 x 16mm 7070 PCB’s in a light but that’s going to take quite a bit of space.
Plus the whole heat management thing.
The useable runtime at anything approaching maximum output is going to be ridiculously short. Due to the small host, heat generated and the single battery.
Throw a cooling fan in there as well. A couple of manufacturers are doing that in off the shelf designs.
The MS03 came out before the 3V xhp70.2 existed (as far as I know) and would have been run off a high powered boost driver. You’re talking about 4.5 to 5 amps per LED output (or thereabouts). Imalent runs the leds at the higher voltage to avoid the huge input current demands which would have overwhelmed the (rewrapped) 40T they used. I tested the RC30 (which had 3 sst70) and it pulled 30+ amps at the tail at startup. I believe it used the same driver as the MS03.
It is possible to run four parallel connected xhp70.3 leds at 3 volts off 1S and get 15,000 lumens or more in a small host is a very tall order and would make the light pretty much just a fun toy in anything but lower modes. You’d need a custom mcpcb, a custom reflector, a 1S fet driver (check out mountain electronics for that) and a stout battery like P50B or JP40.
Wuben X1
tks for the info, do you know any convoy host that is small, accept 21700 and already hv reflector for 3 or 4 led?
yeah this one not so thick so can pocket but i would do 2p instead of 2s to avoid any mismatch → peace of mind