Buckpuck 3023 alternate driver ?

[Tony_J_Ross]

G'day all,

I'm making a new Cree XR-E quad light and I need two buckpucks (1000mA).

Is there an alternative to the Luxeon buckpucks from Cutter ? I don't really want to spend $70 on two controllers.

I need to be able to dim the controllers by the way.

Cheers.

Tony

 

[georges80]

What input voltage? How are you planning to dim?

You may find some other options if you check my signature.

cheers,
george.

 

[Tony_J_Ross]

Thanks for the reply George.

I'm using a Li-ion 14.8 Volt battery 4400mAh.

I'm dimming my current triple with a 3 position swith wired into the dimm leads of the Buckpuck 3023 with resistors to go to about 700mA and 150mA.

Cheers.

Tony

 

[georges80]

Well, given you want to run 4 Cree and 4 li-ion you have little choice but to use 2 driver boards since the Vf of the 4 Cree and the voltage of the 4 li-ion crosses over so neither a buck or a boost will work.

cheers,
george.

 

[mr ben]

the voltage of the 4 li-ion crosses over so neither a buck or a boost will work

I have been trying to figure this one out for a while. Hope you can help --

Say we want to light up one series-wired (4s) MC-E via a driver. The driver + LEDs will need about 14V ~ 15V in total.

I heard that voltage into a driver (from battery) should be as close as possible to voltage out (to LED), to increase efficiency and reduce overheating. So say we use a battery pack of 4 * 18650 Li-Ion cells in series.

It should give:
4.2V * 4 = 16.8V freshly charged
3.7V * 4 = 14.8V on average
3V * 4 = 12V at tripping protection point

Doing quite well so far then.

But the 16.8V is too much but the 12V is too little. So should the driver be buck or boost????? If not, how should it be done?