Some updates for the week!
To summarize, I finally finished a 'beta' version of the firmware, put it inside the host, and now have a single 18650 XHP50 flashlight producing 1700+ lumens of 4000K CRI90 light!
Firmware Work
I spent about an hour or so yesterday and tidied up the basic functionality of the firmware (currently v0.6). It has all the basic functionality - 4 modes at 60mA, 540mA, 1800mA and 3000mA. Using the G2-bin LED I'm using, this corresponds to around 35 lumens, 310 lumens, 1000 lumens and 1750 lumens from the emitter. Keep in mind that if the most efficient bin was used (J4), a whopping 2500 lumens is possible!
The brightness levels chosen was somewhat arbitrary with no specific reason. Mode change goes from level 1 -> 2 -> 3 -> Brightest, with memory mode tested and working. Low battery cut-off was also tested and working. Thermal cut-off was difficult to test, but I did at least verify that it was reading the right temperatures. Clearly more robust testing is required later, but for my own 'demo' torch, this should do.
Obviously a lot more testing is required before I would consider a firmware stable, hence it's now labeled as v0.6 instead of 1.0
Assembly
With the beta firmware done, I loaded it up to the LED driver, then removed the programming header and prepared it for mounting.
As recommended, I also did a spring bypass with teflon coated stranded wire. Above shows the logic/driver side.
And here's a photo of the 'power' side with all the power electronic components.
As some of you may remember, I was doing testing with a G2-bin XHP50 LED with 90CRI and 5700K temperature. I wanted something a little warmer so I opted for a 90CRI G2-bin 4000K XHP50 instead. This time I had some proper heatsinks (from the recommendation of many members here), so I reflowed the 4000K LED onto it - this will go into my flashlight.
This was then fitted into the housing and thermal paste applied between the LED-sinkpad and the housing.
The wires were trimmed and soldered down.
And finally it was assembled into the host! It looks just like the original... but actually contains a light monster!
Above you can see it sitting beside the older XHP50 (5700k) mounted on heatsink, which I used for testing.
The project is done!
Comparison Shots
So how does it compare? Let's take a look at some beam shots. In order to compare, I set my camera to have a fixed manual exposure of 1/60s, ISO 400, W/B 4500K, f3.2. I compared the new XHP50 flashlight with the following:
1) 3000K 800 lumen Greenlite LED bulb (8.4W measured)
2) 5000K 1700 lumen CREE LED bulb (2016 version) (15W)
3) SK68-3W - cheap AA LED flashlight - 1.28V at 2.00A via Eneloop HR-3UTG (2.56W measured)
4) SK98 stock with LatticeBright 6500k+? (6.74W measured)
5) SK98 replaced with Cree XML2 80CRI 3000K (6.67W measured)
6) SK98 with GXB20 with Cree XHP50 90CRI 4000K (22W measured)
All 18650 batteries used in the SK98 Ultrafire host were the venerable LGDBHE21865 high discharge cells.
The above photo shows the unedited images with (1) on the top left and (6) at the bottom right. The result speaks for itself I think! It's extremely bright! Also, I specifically under-exposed as much as I could to (a) retain luminosity data and not blow highlights and (b) since I expect myself to make more, brighter lights in the future!
And finally, with the lenses zoomed all the way in to give an idea of the 'throw':
From left to right:
- LED AA flashlight (no idea what's inside)
- Lattice-bright XML-copy LED in SK98
- Cree XML2 in SK98
- Cree XHP50.1 in SK98
I think it's pretty clear that the Lattice Bright LED does have a smaller die and different phosphor coating than the XML2, and again from the XHP50 which has 4-dies. Hopefully the XHP50.2 will improve the cross pattern. Regardless, I think it's a pretty interesting pattern (which only really becomes annoying at max zoom), so I don't really mind it at all given how much light it provides!
So overall I think this project is a success! Thanks again for reading and following my little project!
Next step is to refine the firmware, do additional testing and see how it does in the real world, and then perhaps start on the GXB17...
[Edit] - Did a little bit of real world testing of the firmware and it appears that thermal management is working as intended :)