Cree Lighting

[Stevens 47]

Originally Posted by Pblais

TaylorBrite is the name of the company but it may not be the only one. You can see them at Discount Marine and Boat Supplies - Inflatable Sales - Defender I found they had the best price at the time a few years ago. We used the two bulb unit and it is exceptionally bright. You can add a dimmer to them so you can economize on the power even more when you don't need it. They are not that cheap but they do use half the power of the fluorescent so that gets it down pretty low. The color is a little warmer as well. Ours is in the galley under the deck walk way above the counter. If you open the fridge hatch it lights it up quite well and lights the entire galley and dinning table too. You might also want a red light to use on night passages as this would blow your night vision completely.

They do make a reading light is you want to get rid of the really power hungry bulbs. I do think for the reading lights the LED's are starting to package up pretty well.

Thanks for that.

[SoonerSailor]

Doghouse -

How many Luxeons do you want to light up? Which convertor are you planning to use? Is there an online spec sheet?

If you are going to string 3 LEDs in series, a 12v input to the buck convertor should be plenty. Maybe the convertor is rated to take a maxiumum of 32 volts input? That would give you nice headroom.

Keep in mind that Luxeons (a Philips brand of high power LED) provide only about half the lumens/watt that Cree and Seoul Semiconductor power LEDs are providing these days.

[SoonerSailor]

Doghouse -
I now see the link to the BuckPucks you are thinking of. I have used a couple of these in the past myself. The ideal would be to drive three LEDs in series while supplying the Buckpuck with the 12v from your house batteries. The 700 mA version will deliver 700 mA through the three LEDs as long as the input voltage to the Buckpuck is at least 2 volts higher than the sum of the Vfs of the LEDs at 700 ma (Vf varies according to how much current is passed through them). If you drive your LEDs at 700 mA, you need to make sure that they are mounted to a decent size heat sink or you will sacrifice light output and lifetime. If you drive them at 350 mA, the heat sinking is not so critical, but for light output efficiency, the more the better in any case. You can just epoxy (JB Weld works well here) the Luxeon (or Cree, or Seoul) stars to a strip of aluminum stock. Keep in mind that at 700 mA, each LED is generating about 2 watts of heat that it needs to get rid of.

You could use a 700 mA Buckpuck to drive two strings of three series LED, with the two strings in parallel. If the total Vf of each string is the same, each string will get half of the total current, or 350 mA. This is fine, but if the two strings are mismatched one string will get more than 350 mA and the other less. Its safest not to parallel LEDs unless closely matched, however.

I see the Rebel Endor Star on the website you refer to, with three Lumileds Rebel LEDs mounted to one star. This might be a good choice, the Rebel LEDs have efficiencies comparable to Cree and Seoul. You would really need to fix these stars closely to a nice heatsink to drive them at 350 or 700 mA. If using flat aluminum stock for a heatsink, figure on at least 1 square inch of heat sink for each watt to the LED, or about 8 sq inches for each Rebel Endor Star driven at 700 mA.

[bstreep]

I have Luxeon Stars and Buck Pucks extensively in our boat. Replaced ALL of the fluorescent lighting...

Yes, you can run 2 sets (in parallel) of 3 Stars that are wired in series. Just make sure the Buck Puck is close to the stars (3 feet?) and that the stars are heat sinked.

Yes, I think you have a misprint. Try www.ledsupply.com.

Paul, I believe that with most "dimmers", they are just a resistor/rheostat, which doesn't save electricity...