Recent discussion on a Harbor Freight group indicated the HF Roadshock and the KCHilite C-Series C3 are very very similar. Both use the same housing, the C3 uses “V2” of the driver board, the HF uses “V3” but the boards look identical. Being only $25 (per) from HF I grabbed one to mess with. Initial results are pretty marginal. I wouldn’t use them as supplementary lighting on anything that goes over 45 mph, the floods may be good for tractor lights.
That said, why not try and make them better…
Claimed output is 1050 lumens
Claimed power is 15W
LED is “Cree” and it looks like it might be the XP-G3
Numbers don’t exactly line up but it is Chinese marketing…
Looking at switching the emitters out and swapping to elliptical TIR lenses.
That said, my electronics theory is rusty and my driver theory is nearly non-existent. Any help available in possibly modifying the board for more output? The inductors look a bit small (two in the corners), not sure how much more power can be pulled out of these. I cannot identify the sense resistor, if someone could point it out for me I would appreciate it.
Looks like a fun project. I can’t help you much with modifying the driver, but I agree with you that it doesn’t look like the components can handle a lot of power. Also the LED pads are prob not DTP which also limits possible power. Personally, I would take all that stuff out and basically use it as a host.
Sadly I think getting more power out of the driver will be key to getting more light. I don’t know their rational for the claimed 1050 lumens but the XP-G3 at highest bin is 205 lumens at 350mA. I need to sit and figure their math to get four LEDs to 1050 while consuming 15w.
I need to get the board out to look at it better but I think it is DTP. The board is flat agains the housing (two outside screw holes) and there appears to be thermal compound behind the board.
I’m still struggling to get the board out. They appear to have poured some sort of sealant on the power wires after assemble. It holds the wires in place and helps seal the whole thing from moisture, it also flowed around the edges of the driver board effectively gluing it to the housing.
Ultimately I will space the driver forward a bit to bring the (shorter) TIR lenses close to the front glass. Unfortunately swapping drivers too would negate much of this project. The added cost of drivers and mcpbs will likely make this cost prohibitive
Did a little digging here into sense resistor mods and located the two for this driver. Since I don’t have any surface mount resistors on hand, and I like to live dangerously, I just shorted the sense resistor to make it effectively direct drive.
Ultimately power draw (at battery) went up from around 1.3A to about 5.5A.
Output did increase, but not significantly so. Looking at the output curves for the XP-G3 this is a bit surprising since I more then tripled drive current. But, to my untrained eye just casually doing this in the garage the output could have been just less then double, which would jive with being a fair bit below quadrupling output.
