lux V advise

Hey all
I've been learning a lot through the process of trial and error. However when playing with luxV's and driver boards errors cost a lot of money. So i've made enough magic smoke to know whats good to try and bad to try. However i'd like a second opinion on something. I'm working on a little project that i'll unviel at the bay area get together. My choices for the luxV(i believe U forward voltage) are as follows. Badboy 750 with 6 volts input voltage. Or I could direct drive it with an input voltage of 8.4volts to start and leveling off with 7.2volts. This light is basically going to be for fun and really not practical so a couple minutes of good run time will do. I want bright over practical. Any advice on which way to go.
jimmy

BB750 will work. If you DD, you should use alkalines. From the numbers above, it sounds likeyou are using rechargables. I'd put a 0.5R resistor in series or use a driver such as the nFlex, CC5WB, etc... from Georges80 or something equiv from the Shoppe

It will only work with lithiums. Not enough power from alkalines in this project. very limited space here. So i'll asume the lithium will be brighter than the bb750 but i guess it'll also smoke very fast.
jimmy

If you use Lithiums, eg L91-AA's, or Li-ions, I'd suggest a driver like the BB750 or the ones I suggested. Use the BB750 if your battery voltage is < ~7V or the ones I suggested if your supply voltage is >> 7V.

Having said that, I have sucessfully DD using 6 x L91-AAs to to a VWAV in a Hotlips heatsink within a OA2D host /ubbthreads/images/graemlins/grin.gif

Just MHO, but with so little voltage headroom, I would just use a resistor. A 1 volt or less drop, 1 ohm or less resistance, 1 amp nominal - 6 watts coming into the Lux V, less than 1 watt going to a resistor - actually fairly efficient. Then there is the minor point that many of the driver boards really need about 1 v of headroom just to run.

I sold a WXOT (the two I had are gone) to a fellow cpf r who did a direct drive routine with good heat sinking. It ran around 1.6 amps for a very short time - then he sent a PM telling me he had killed it. More than 7 watts is a real push for a Lux V cooling package.

As you noted, these can get expensive, and nice bins are not only expensive, they are hard to find. Even a U bin Lux V is really bright, just don t kill it the first day.

JimH, from the Voltage and my talk with JimH, you're probably trying to get 2x 14500 Li-Ion to pump your LuxV right? For the little AA "contest"?

From my limited experience with 14500 it won't provide enough current to fully drive your LuxV. From my D-Pill the most current I ever got of them is 700mA after charging overnight. Most of the time it's more like 600-500mA /ubbthreads/images/graemlins/frown.gif

Remember the rule is just use 2AA form factor that doesn't mean you're stuck to a MiniMag /ubbthreads/images/graemlins/grin.gif

ya johnathan you got me. I'm going to either use 2x14500 in a direct possilby resitored drive, or use 2x3volt lithium primary cells pulled from a crv3 with a badboy 750. Now of course i'm completely thrown for a loop as to your comment on "Remember the rule is just use 2AA form factor that doesn't mean you're stuck to a MiniMag ". I'm sure i'll sleep very well tonight with that stuck in my head
jimmy