Powering all Tri-Cree LEDs at once? Requirements?

[Richei Blasto]

PS - can anyone explain what the CTL and REF wires are for and how they're used in the 6 wire version of this BuckPuck? Thanks!

[Silver Serpent]

...Option 1 - 1x 3.7 volt li-ion 3400 mAh battery (the higher mAh the better as each die will want to draw 1000ma for 3A total...

mAh is a measure of battery capacity. A 3400mAh battery can provide 3400mA for 1 hour, or 1700mA for 2 hours, etc. It does not tell you what the maximum current draw you can use. The higher mAh batteries just let you go longer before you need to recharge. Higher capacity batteries typically handle higher discharge rates as well, but most any 18650 cell will handle a 3A discharge rate without trouble.

So, the question becomes how best to get 12v-15v into the BuckPuch to get them to full brightness. 4 x 3.7v Li = 14.8v would seem perfect, except that fully charged you've got 16.8v - I don't know how much of a problem this would be given the 15v max rating, but you could always use a voltage regulator (or a resistor!) for insurance. 3 x 3.7v Li is 12.6v fully charged, so that's good, but at their average voltage you're only looking at 11.1v, so you might not be getting every little bit of brightness out. Of course you might get better numbers using Ni-mh or vanilla alkalines etc.

Not sure where you're getting the 12v-15v range that you're talking about. So long as you've exceeded the combined Vf of your LEDs and not gone over the 32v max input for your Buckpuck, you're perfectly safe. If you're driving 12v of LEDs, it doesn't matter if your battery pack gives the Buckpuck 15v or 25v. It'll work exactly the same.

The CTL and REF wires useful for adjusting the output current of the Buckpuck. You can put a potentiometer on those wires and it'll act as a dimmer switch.

[blur]

Lets say we wire the 7.4 pack with buckpuck to the tri cree all blue in series. I understand that this setup would only really power 2 dice fully. but if we did add the third die in series as well, would the first 2 be fully bright and the 3rd be a little dim or would all 3 be the same brightness but on the dim side?

[Forgetful Jedi Knight]

All 3 might light up, just barely. "More" is not always "better", just wire your 2 in series and call it a day.

[Silver Serpent]

Agreed. 2 properly lit LED dice will look a lot better than 3 poorly lit dice, which is what you'd get if you wired up 3 in series with a 7.4v pack.

[Richei Blasto]

Thanks for your reply, Silver Serpent - my mistake re the reference to max 15v on the BuckBuck - my only excuse is that my brain is full!