Led projector modification

[ericg]

Hi!

I have recently purchased a set of 2 led projectors each made of 4 Cree XML T6 driven up to 3000 lumen.
Projectors are similar to this model but in black:

From the forum reading, I understood it is a generic model pushed far above the cooling limit of the case, but ok, it is done!
In fact they are working very well and stay cool as long as there is a good airflow. The temperature limitation is working well and the projector go from 2 A to 0.5A when overheating.

I need to have two mode on this projectors: a low mode (estimated at 300 mA) and full power, control by an outside switch.

I have tried to dim then with such device:

It is working but the led's are flickering a little bit at low power, I think it is due to the PWM placed before the led driver.
So I'm trying to find various solution to get a correct dimming.
The 4 led's are connected 2 serial then 2 parrallels. The driver has the circuit reference erased:


I'm trying to limit the current to 250 mA-300 mA per projector (tested with my adjustable power supply), which give roughly 6.5 V to the projectors.
First option is to use an LM317 as a current limiter, but it will become hot...
second option is to use such kind of driver in line with the projectors http://www.dealextreme.com/p/mr16-1...urrent-regulated-led-driver-8-40v-input-13557 but I don't know if it will work to have two driver in line...
third option is to replace or modify the current driver to have a two mode selectable by a switch, maybe I could reuse the PWM dimmer to control a dimmable driver.

As I don't know the chip onboard of the fitted driver, the modification maybe complicated, and maybe the replacement is the best option!

By the way, if someone knows where to find such housing without any electronic inside, I would appreciate!

Any idea is welcome!

Eric

 

[-Virgil-]

Re: Motorbike mod

Please tread very thoughtfully here; you are edging very close to advocating/discussing illegal lights on an on-road vehicle, which is not allowed on this forum. For safe and legal use of lights like this in traffic at night, you will need to dim them down to no more than 125 candela peak intensity -- less than that if you've got them mounted anywhere near the bike's turn signals, which are required to produce only at least 100 candela. If you are using them as daytime running lights, you will need to dim them to no more than 1500 candela peak intensity -- again, less than that if close to the turn signal, or, better, disable the running light on the signal side during signal operation.

If you aren't able to accurately measure and precisely adjust intensity, then you really must not use these in traffic, day or night.

 

[ericg]

Re: Motorbike mod

Please do not forget I'm located in France, not US, and the law is not the same.
For the sake of the discussion, please consider my request as an off-road option and if needed I may re-write my technical question without even dealing with automotive...
Anyway, if my subject is outside forum rules, please discard the thread, no trouble!

 

[Alaric Darconville]

Re: Motorbike mod

Please do not forget I'm located in France, not US, and the law is not the same.

Indeed, ECE regulations (for example, R87 and R48) may be more stringent than US law.

 

[ericg]

Re: Motorbike mod

I have edited initial post to cancel any reference to automotive use.
Is it possible to move the initial post in appropriate section for technical matter?
My concern is purely technical and I don't want to create problem to the forum by posting innapropriate content.

Thanks in advance,

Eric

 

[-Virgil-]

Re: Motorbike mod

My caution to you, and the candela values I cited, were in accordance with French law, not American. The French vehicle lighting regulations are quite a bit more strict than those in force in North America.

 

[ericg]

Re: Motorbike mod

Ok, I got the message I think.
Once again, I didn't want to initiate a discussion against the rules of the forum, so please close this thread, I will ask only technical question in the appropriate section.