XML L2 T6 Driver Help

Just about to take my first venture into upgrading what is already a "reasonable" light.

The unit - TrustFire TR-D014 runs at 7.4v but I would like to drive thge unit better and be able to program the UI myself.. so being based in the UK, I am struggling to find a supplier with a choice of drivers so, can I ask you guys, where from and what driver would be a good upgrade for this light.

It has 7x Cree XML2 T6. I wish to keep the 7.4v configuration so your help is appreciated. The driver board on this unit is 45mm diameter and there is plenty of metal for getting rid of heat. This light is quite a bit under-powered at the moment and I would like to get the most out of it. I am running an 8cell 2S/4P 12Ah battery pack. TIA.. cheers.

I've not seen a driver that can boost 6V to 24V at anywhere near 3 amps. Also, I've never seen a driver documented well enough for you to write your own UI, though some are simple enough that you could look at the board and figure out what you need to know. Or get a driver with a PWM input and build a controller board. That should be simple enough for anyone who can write a UI.

If you could wire the battery as 4S2P, the HBflex and HyperBoost from Taskled have the hardware you need, and you might get enough info from George or from looking at the board to be able to write your UI. Or you might find his flexible enough to suit your needs. Actually, the HBflex operates down to 7V, so if you could sacrifice some battery life, you could operate it off a 2S pack.

Thanks for your reply. Battery packs I can wire to any configuration as I have loads of 3.7v 3000mAh decent cells laying around from previous ideas. I do have 7.4v & 11.2 & 14.8v chargers but the two first ones are the best chargers and are very good smart units, one from Lupine and one from Trail Tech whereas the other is just some random brand.

I am guessing that the typical 14.8v configuration is popular because it has the options to do so much more.

By "programming" I meant - to be able to configure the driver output so for example I could choose how many modes the light had and what each mode did and how much output it had or even go stepless; to that end, I would probably find most UI's already have that option.

I also guessing that on the board the light came with, it is a very basic board with limited configuration options hence why the LEDs are not being driven to a 100% - one guy over on MTB has writen a review on the light but has not as yet gone into any details about upgrades - http://forums.mtbr.com/lights-night...t6-4-mode-3000lm-bicycle-light-lc-907810.html

As always, I appreciate the feedback from those who know more about this stuff than me.. cheers.

You say you're keen to stick to the existing 7.4V configuration, but what about completely bypassing the existing driver circuitry and driving the 7 LEDs direct with your own board? If you can be flexible with the drive, then finding an option to suit your preferred battery voltage (due to the chargers, as you say) should be no big deal... I think. It would be a bit Heath Robinson, but how about getting a high power driver from eBay and putting together a control board yourself as DIWdiver suggests? There are lots of cheap drivers that can manage lots of power in fairly small packages that would probably be a good basis for this.

The Taskled drivers would run fine on a 3S pack, but you would be limited by the input current. That's the problem with running high boost ratios - the input current is really high.

IIRC, those have a max input current of 6A or so. On a 3S pack running down to 3.0V/cell, you'd have 9V, so a max input power of 54W. Running the pack at 4S, or 12V when running low, you have 72W. After the losses in the driver you'd have an output power in the mid 60's, which is almost to the rated power of the LEDs.