DEAL ENDED - DX XM-LT6 900-Lumen 5-Mode White LED Flashlight - Titanium Color (2x18650) - $29.99 (Normally $41.30)

I don't think you'll be able to screw the handle in if the pill gets more than about 2mm longer. Not sure how you'd make battery contact.

If you hacksaw the pill ~10mm below the threads, you could use a piece of 1" copper pipe connector that fits around what is left to replace the part cut off. There's a gap between the two of about 0.02" to be filled w/ copper sheet - they'd fit so tight you'd have to pound the fitting onto the pill/sheet with a hammer.

It would look like less material, but would actually be heavier. The dx sst-50 driver battery board would be almost an exact fit (to U.S. pipe size anyway). The height might be an issue (~1-2mm?) but I think the driver could be squashed enough to be fine.

The copper would cost ~2x the price of the manafont driver, but you'd have some left over...for the next hack job LOL

I did some new measurments on my modified driver, and now I used newer, better cells with lower internal resistance than earlier, and calibrated my DMM resistance to the tailcap resistance. Now I got "only" 1.69A with almost full cells. Earlier I measured 3.2A led current, and calculated from this, the efficiency of the modified driver is around 80%. Not too good, not too bad.

calculation:

voltage of the cells under load = 2x 3.95V = 7.9V

1.69A x 7.9V= 13.35W this is the input wattage

estimated output wattage on the led:

3.2A x 3.35V = 10.72W

efficiency: 10.72W/13.35W= 80.3%

Okay, I will try the driver with higher output current.

I'd say why bother, but I'd rather you go ahead and then maybe you'll discover some improvement to the manafont driver for us

I'd love a 5 mode driver with 4.2, 3, 2.5, 1, .25A and temp controlled step down

whiskey taste - beer budget

I don't want to spend more money ... :)

Overall brightness was 8% less than BC40 with stock driver, now 15% more. The led current is around 3.6A now, and the consumption is acceptable. This is a good compromise solution.

earlier I made a runtime graph: https://budgetlightforum.com/t/-/5736#node-6739

only for 1 minutes at 4.3A, this is a good boost mode and you will get -I don't know exactly- 15% more brightness than at 3.6A, but after some minutes, because of the increased led temperature, the brightness will be as low as mine at 3.6A, so this is enough for me. ;)



and a new graph, UF D1 with modded driver VS Jetbeam BC40 (relative) overall brightness


after 7 mins, the UF head reached 35°C, BC40 43°C


great post!

how about those head temps - awesome cheap host!

it doesn't look like you need to spend any more money...actually, if you use more than 1 minute then the 4.3A is NOT the way to go

are you taking manual readings and plotting or do you have a meter with light output?

I'd like to get set up to do that. I'm sure a USB thermometer is cheap. I think I saw one on DX. I could check it's accuracy w/ my multimeter.

I want to test temperature before and after stripping anodizing.

I think ~3.5A is best for the way most people would use this, but for me....BOOST!

manual reading, not a big work

no, with the modified stock driver

stock driver - manafont driver

on the manafont driver, I've shaved the board the coil sits on, squished the coil to the center and as close to the board as I could. I also shaved the base until just a hair line of the metal ring on the top side is left.

On the battery contact side, I soldered to stock spring on and soldered on a copper ring, to make better contact with pill, but also as a retainer, since boring the pill removed the stock shoulder for keeping the driver in place.

stock driver sitting in modified pill next to manafont driver

manafont driver after plastidip, which was done to insulate it from the pill. you can also see that I've added 'circuit writer' (silver in adhesive) around the edge of the driver to restore the connection between the tiny bit of brass left on the top side of the bottom board with the negative contact on the bottom.

Here's the shim I made for heat sinking the pill to the collar/body. It is a copper pipe fitting with 30 gauge sheet between it and the collar. I fit it to the pill by wrapping the pill with desoldering wick, putting the shim over it, heating the whole thing with a torch then flowing plumbing solder into the desoldering wick. The solder won't stick to aluminum, so I could just pull the pill out of the shim afterwards. I sanded it just a bit because there was too much friction between pill and collar...eventually I would have stripped the threads. I had to pound it into the collar with a hammer - it isn't coming out unless it gets cut out.

The second pic is to show there's still a lot of contact after sanding...

and here is Foxy, watching 'Call of the Wild' on hulu while I ignore her to work in the shop she kept looking behind the center speaker, as if she'd find a husky there

very similar drivers, would be good to know what kind of mosfet sits on the manafont board

All major components are sanded down to deter identification.

dthrckt - great mod !

thanks!

oh wow, I didn't notice that, glad I didn't peel the plastidip, only to find that out lol

I used a 0.33ohm resistor, so you should use a lower one, maybe a 0.22ohm.

I tried with a 1Ω resistor (soldered with low temp) and now it doesn’t work. Y also changed the cables, and I inserted very thick ones so there must be the problem. With a Manafont driver it should be fixed.

Where did you solder the resistor? I hope you soldered paralel to the "sandwich" resistors wich is beside the coil. And 1ohm is too high, it has almost no effect.

I use a solder-station with regulated temperature, I call low temp to ~350°C

Yes, I did it right, in parallel to the sandwich (mmmhhh sandwichs), may be I screwed it up trying to connect the batteries without completely assembly, and could do some short-circuit… maybe, but don’t really know. I chose 1Ω because I only have 1Ω and 0.1Ω, and I red that with 0.56Ω it wasn’t stable… so I wanted a little bit more current until new driver arrives.

got some stuff from DX today including sst-50 driver. It fits in my modified pill (I did have to squash the coil a bit), well...it sort of fits...the battery board sits on the bottom lip. see below. kind of hard to see because the color of the board.

But, I didn't even test w/ it because I think it will have higher current and heat. I'll save it for something else...

If you do try to use it, be careful that you don't crush it with the battery tube. Mine won't do that but if I could get another 1/2 turn on the tube it would.

In theory... you can short-circuit the driver with an ammeter (instead of the LED, you put the ammeter) to know the output current.

I didn't do it yet because I can't use my power supply for now, and with batteries isn't comfortable to do the connections...

Higher the resistor lower the current. If you want more current you have to use lower resistor. The goal is reduce the resistance of the sandwich resistors, wich is 80milliohm in my case.

It was stable with 0.56ohm, but my measurment wasn't so accurate, the current very depends on the cells, multimeters, leads etc, and that was the problem in my case only.

not afraid. I would estimate I removed about 20% of the mass from the pill, but it screws into the reflector, which screws into the head, and the threads are fairly tight (lots of contact) so I think it will be fine. I have a U2 emitter on the way, and once that is in there I'll use arctic silver ceramique on the threads in the head.

I also added that copper shim, but I don't think you need to.

It really depends on how you'll use it though. I used it on high for 10 minutes last night and it was so cold outside that the head hardly warmed up at all...

I used a mill bit in my drill press to bore it but a spade bit would work. it is pretty soft (probably not alloyed) aluminum.

OK, I couldn't resist and I used my computer's PSU to do the trick. I short-circuited the SST-50 driver with an ammeter, and the result is: 4.30Amps (standard driver).

Very nice for this flashlight, and for every XM-L with good heatsink.

May be one driver can vary a little bit from another, but I bet they all are near 4.3A.