I'm looking for a 3A driver for a custom bike light project

[BobBarker]

I'm working on a bike light for the Mrs and I. The lights are going to have 3 XM-L2s and have about 70+ sq inches of heatsink surface (mounted to the bike head tube). The LEDs will be driven by two drivers (1 on one, and 2 on the other)
I have been looking at the Taskled drivers, but they are expensive. I don't need (or want) any "modes". I just need the ability to set the brightness (just in case 3 XM-L2s are too bright , and the ability to turn it "off" without having to disconnect power. Basicly I will have a single switch to tell the 3 leds to either be full on or turn one off and dim the other two (and then back again when it's pushed again).
This will be part of a full light set (with tail light that is running 3 triple XP-E stars (running at about 10-15% at night and on full w/2.5hz flash during the day).

I've got everything but the two main drivers worked out.
If you guys have any suggestions, I would be quite thankful.
-PBB

 

[torukmakto4]

A low cost option would be to use some AMC7135 based flashlight drivers. One per LED. They are available with output currents close to 3A and cost pocket change. You would need a 1s battery setup for these (presumably with a lot of capacity, so a big lipo pack or a bunch of 18650 in parallel) and low voltage protection would be accomplished by the drivers without any need for protection circuit nonsense in the batteries/packs. The control can be a switch - try DPDT, center off. One driver goes to common pole 1, two others go to common pole 2, power goes to position 1 on pole 1 only and position 2 on both poles. Position 1 powers one driver and position 2 powers all 3.

 

[BobBarker]

I guess I did forget to mention that part... The pack will be a 4-5S/2-3P pack. Still looking at what will work best. Total power draw is going to be around 48w (figuring around 85% driver efficiency). I will need a pack that will run for a minimum of 2 hours, but looking more at about 3 hour run time.

I've got all the electricals worked out, I just need to find the drivers (and I'm not really wanting to spend $30 each on them (for the TaskLED drivers). Basicly I just need drivers that are rated for 3A (and an input of 17-21V) that has external dimming, that don't cost a small fortune. As it stands, using 4 of the Taskled drivers would end up costing $60 each light. So basicly about 20% of the entire cost of the project (that is quite elaborate)