I built my first custom light, an S2+ with 3 Cree XPL emitters and a 17mm Dr.Jones board. However, it seems like the light can not do its full output. I am measuring 3A across the tailcap at maximum brightness. I bought the board because it has DD output, but it does not seem to be working. Theoretically this should be a 3000lm light at 9A, which the board and battery should be able to handle. I am using a Sony VTC6 for testing. This is the board 17mm DrJones H17Fx Driver w/ lucidrv2 - 7135 + FET
Anyone got ideas for how to troubleshoot this issue? Thanks.
Gratz on the first mod! Bummer that it is not working out as planned
Hmmmm… I do not see a FET on that driver. Looks like to me to be a straight 8x 7135 to me…
Personally, I would have gone for THIS driver for a triple and I’m a huge fan of MTNElectronics’ drivers.
I measured using a multimeter, with one contact on the negative terminal of the battery and the other on the non-anodized rim of the tube with the tailcap off. I can tap the contacts that way and cycle through modes as though I had a switch.
man, maybe I’ll pick up one of those next time. The driver I linked to does advertise that it has a FET direct drive channel, but it could be mislabeled or something.
Exactly what I was thinking, hopefully MTN could clear that up.
For single LED builds, a FET driver on most LEDs (like the Samsung and the Luminus SST20 for example) would kill them… In fact, for my upcoming single SST20 and Osram builds in an S2 (no plus) I’m using THIS to drive them with limited current
@KnHawke Nice. So I actually built two lights today, a red S2+ with 3x photo red Cree XPE and the qlite board you linked. That light works perfectly, the only issue was the retaining ring wont fit over that driver so I had to solder it in place. Totally good driver if you want max 3A.
That is a FET direct drive driver. In order to get accurate current measurements, you cannot measure with a digital multimeter (DMM). You will need to use an amp meter.
For the QLITE driver, you could also rim out the inside of the retainer ring to fit over the 7135 chips rather than soldering. I’ve done that numerous times for drivers since trying to remove a soldered in driver is much harder.
The needed meter is a “clamp meter” like this one.
This type uses a sensor. The jaws are clamped around a single conductor to measure current flow in the circuit. This requires a jumper wire of heavy gauge to be used in place of the tailcap of the flashlight. The meter jaws are clamped aroung that heavy wire.
The DrJones driver does definitely have a FET DD mode. I have used this driver in several lights, including one in a C8 with a single Samsung LH351D. I’ve also used LH351D in a D80v2 with the factory driver (which has a FET DD mode). The Samsung LEDs handle direct drive just fine.
Thin wires to the LED, regular springs (with no bypassing), other stray resistances can kill maximum output.
Plus, as was already said, DMMs directly measuring current will insert their own resistance, and the leads are like 4’ total (2’ red and 2’ black) of fine Cu hair inside thick flexible insulation. Gotta use short fat wire to bridge the cell to the case, and a clampmeter around that wire.
And 9A in a S2+ will heat up like a curling-iron in no time, so keep that in mind.
Thanks, I had not bypassed the springs yet, and that may be the issue. Yea, I was not planning on using it at full power for more than a few seconds at a time and this is not a light I would hand to someone without warning them. I will look into the meter I need to measure current more accurately, I was kinda wondering about the resistance in the multimeter when I tested it but didn’t know what else to use.
