Today I built up a Jaxman E2L host, using a BLF-A6 (FET+7135) driver and 4000K Luxeon V leds on the new led4power 4040 triple board. In fact, I did this build to check some real world performance of this new board type.
Special about the new boards that he sells now is that they are not DTP, so none of the solder pads are electrically connected to the core, but the dielectric layer is so thin (it is just an anodisation layer on the aluminium core) that the board should perform just as well as a DTP board.
I won a number of these boards in a small quiz that l4p held to promote them, and I happened to be online () just as he posted it so I was the first with a correct answer. And I even received some bonus boards, thanks!
The 4040 triple board is exactly 20mm diameter, as it should be, but the E2L host annoyingssely just allows 19.5mm, so it needed some slight shaving and that can only by just be done while still clearing the circuitry on top. But I do not know how I would have done that without my disc sander. The shaved board:
Reflowing the leds was no problem, and since I'm not using the FET-option on the ledboard, the ledminus wire was soldered on the FET-drain pad.
The leds fit tight but nicely under the Carclo optic.
Both springs were bypassed with 20AWG wire, the rather long tail spring replaced with a shorter one to make a 18350 cell fit less tight in shorty form. I replaced the switch because I melted the stock one during the spring soldering. The BLF-A6 driver received the 'voltage spike-fix' (not really needed for this driver, an OCD-thingy), a 680 Ohm bleeder resistor and 20AWG ledwires. A lighted tail is planned at a later moment.
The only real problem was soldering the ledwires on the ledboard. It was immediately clear that this dielectric layer is something special because even though the pads and wires were pre-tinned, even my super-hot 80W solder iron (admittedly with old rotten tip) struggled to get the solder hot enough to join, the heat was just sucked away to the core: I had multiple cold solder joints (the wires just sprung loose when the light was on max for a few seconds) before I finally got good connections. I ordered a new tip for the solder iron to get better work done next time.
So the low thermal resistance dielectric layer which is the key quality of these boards, has a nasty side-effect: not just under the led but also under the solder pads the heat is sucked away to the core with record speed.
So I got the light done and did some measurements. I also measured my modded Emisar D4 with Luxeon V leds again for comparison, even though it is a bit different light, and it has 4 Luxeon V leds compared to 3 for the E2L. Ignoring other differences, having 3 leds the E2L could theoretically put out 75% of the D4. But probably a bit less because the E2L uses a clicky switch and a bit lower quality FET, both adding some extra resistance. I measured output on a fully charged 30Q battery, at 3 seconds (first stable reading of my luxmeter after an output change), 12 seconds (first stepdown of the D4) and 30 seconds for the E2L.
D4:
3 seconds: 5200 lumen
12 seconds: 4850 lumen
E2L:
3 seconds: 3650 lumen
12 seconds: 3450 lumen
30 seconds: 3170 lumen
The D4 even performs better than when I measured it first a few weeks ago. It looses 7% output in 12 seconds. The E2L looses just 5.5% in 12 seconds, already a good sign for the ledboard. 3170 lumen at 30 seconds is also very good for this very small triple. Only the output (at 12 seconds) is not 75% of the D4 but 71%, a small difference that can easily be attributed to FET and switch, I do not blame the ledboard. The longest runtime that I checked on turbo was 40 seconds, which is the fixed stepdown time for the BLF-A6 driver. No angry blue light and no damage could be observed.
I give this board a very good rating for performance, when doing this mod I did not not see any worse performance compared to a DTP board (better??). The only challenge is getting the ledwires soldered, a problem inherent to the good thermal properties of these boards.