ok so battery
and driver
http://www.kaidomain.com/ProductDetails.aspx?ProductId=10653
yay /nay
Looking good. The only thing that may be a problem is that the KD driver wants 5-12V so you'd want to use 5 cells - those cells are the ones I have and they do work well. Apparently they perform well up to 15A - the Varapower takes 13 or thereabouts. You'll need a 4D host as you aren't going to get 5 Cs into a 3D Mag. 4Ds are 248mm long and 5 Cs are 250mm so there should be no problems in a 4D. It might be possible to get 5 sub Cs into a 3D but I doubt it as they'd come to 220mm long but if the spring is completely removed they are narrow enough 22.5mm to fit right into the tailcap and there might be enough length.
B&Q ought to be able to supply you with some appropriately sized plastic plumbing pipe to make an adaptor. See my pictures of the Varapower for an example.
The alternative is 6AAs in a 2D or 9AAs in a 3D but the adaptors to use these are expensive - the 9AA-3D is $45 plus postage from the US. The Fivmega ones cost more. Runtime would be short with this approach though.
thanks for the heads up Don, how about running it on 2 18650 would this work if i get some decent AW IMR ones? what sort of run time do you think i would get with that set up 20mins
2 18650s should work fine. It is roughly a 15W device so:
We need 15W + driver losses from the cells. We have let's say 7.2V on average so we are asking the cells for 2 and a bit amps. This means ordinary 18650s, even protected ones ought to work. Say the 2400mAh Trustfires which ought to give you around an hour depending on the efficiency of the driver which is probably around the 80% mark. You probably won't need a metal reflector at that wattage, just cut down the Mag one a bit. If you are getting a new Mag for this, go for one of the new Rebel ones which have a much deeper reflector so should throw better. But check that the heatsink will fit first. Just make sure the back of the reflector can't touch the LED contacts and short the driver. That would not be good...
If you kill a Mag reflector trimming it, I have more somewhere.
Cool thanks Don so now were moving somewhere i was going to use the mag i already have it's one of the old incan bulb ones so that should be ok ?
I'll start getting some parts together :-)
Of course i have totally forgotten the most important component here.. THE LED !! dohh
Where can i get a DECENT sst-50 led from?
But they appear to be out of stock and they appear to want a minimum 500 euro order...
Probably not helpful.
Thanks Don what do you make of this one from the bay of E worth risking ?
Looks OK to me - AFAIK WJ is the brightest bin actually available at the moment.
You need to make sure the form factor matches your platform. For example, there's some dude on CPF who sells pills for sst's, but they expect a module with a simple round mount.
edit: actually, my bad, that was for p7/mce.
Back on topic of indecently long flashlights with standard batteries and high output, tada ... I present the "Solarfarce Extreme 4xAA R5 3-Mode". It's not the final version, but I'm already quiet happy with it.
Solarfarce Extreme, Superfire WF-501C, Solarforce L2R, Hugsby P32, Maratac AAA SS
Solarfarce Extreme consisting of: L2 Flashlight Body Tube with Extension Tube + Solarforce L2 Flashlight Extension Tube , 18 mm O-ring - to avoid shortening the backside of the driver, DX XP-G R5 on 14mm base, 3-mode high voltage driver with memory, an empty orange peel XR-E dropin (similar to this), thermal grease, a spacer/washer out of laser printer overhead transparencies to keep the contacts of the driver from touching the brass pill, a second spacer/washer (looking like this) to keep the contacts of the emitter from touching the reflector, a third spacer - aluminium tube (203 mm long, 18 mm outer diameter, 15 mm inner diameter, with a sheet of paper surrounding the whole.. for a pressing fit ) - to keep the 4 AA Eneloops rattling to a minimum and some aluminium foil to keep a cool head 
.
close up of the XP-G R5 dropin in the head
The tint is extremely nice, I wonder if I won the tint lottery, because it looks almost neutral/warm to my eyes.
Brightness with 4 x AA, 1 x 18650, 2x 18650 seems the same to my eyes, I would say similar to the SKYRAY S-R5 (on 1x18650) or even brighter.
The beam is the complete opposite of the Skyray S-R5, due to the "wide" OP reflector of the XR-E dropin in contrast to the "narrow" SMO reflector of the Skyray. (Does anyone know, if they are available somewhere separately? DX SMO reflectors have a different shape.)
DX sent me the wrong driver I wanted 5 modes without memory and got 3 modes with memory, lol ... anyways... 3*SB 1400 mA driver are en-route.
Maybe I will do beamshots, when I am able to find a white wall.
That is one long light!
That looks like a lot of work...
On the other hand it's essentially just an extension, a dropin and a spacer extra to an already existing light. I'm just listing everthing so anyone can rebuild it, if they like. (Could you remove the full-quote Don?... I wanna edit a few things, thanks.)
The result is worth the effort.
Want any more deleting? No problem..
The problem with a in-line design is that it's quite long and large for 4AA. 4AA in a holder is just barely larger than would fit in a D size tube.
It might be good if there's the flexibility of 2-4AA, but that would require a buck/boost driver. The smallsun 4AA video above shows at least that light is poorly regulated. It is direct drive or something? Hardly any light at 2AA, and probably burns the emitter at 4?
That was exactly why I made the Solarfarce Extreme (18P) - so that I'm always in the buck voltage range, even with NiMh (4 x 1.2V = 4.8V full, 4 x 0.9 V = 3.6 V empty) and can use standard high voltage drivers (designed for 2 cells LI-ION) and XP-G R5's driven hard. Low voltage drop-ins or drivers with such high output are very rare.. to none existent. This light is still tiny compared to a MAG 3D, but it has multiple times the output. When the parts for it arrived and I put them together for the first time... I thought - OMG that's way too big... now after 2 days it is my absolute favourite in my collection. Actually ... just holding it is nice... this is what I meant in the first post... D-cell Maglites are big, but the proportions are right. My L2R feels "wrong" ... the Solarfarce Extreme feels "right", I can't explain it better.
If anyone knows such a driver you mentioned, I need the link. The fitting spacer is already there for a 2xAA setup (9P).
The Superfire above on the pictures is made this way. I have got the whole idea from old's Superfire mod on jayki.com .
I have received 2 meters (6.56 feet) of that inner spacing tube... I could now play a nice game of "my flashlight is longer than yours" but my 14 * AA Eneloops wouldn't be enough.
Add 2 more AA's and it'll look like a mini baton... I like it. Heck, might as well add 4 more to get the total effect. Its hard to beat the power potential, usefulness and form factor of 18650's, especially 2 of them in series. Still, you succeeded in creating a fairly versatile medium sized light that will prove useful under a wide range of situations.
I wonder if midget policemen would appreciate something like this? -just kidding!
A picture with a new perspective... it doesn't seem this big any more.
MAG 3D (not mine), Solarfarce Extreme, Ultrafire WF-501B (not mine)
You could always store it in the 3D :D
How did you get a photo that makes the 3D appear to have a bend in it? Or is it just my eyes?