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.