different ways to use a nexgen sandwich

So my nexgen sandwich is on the way here and I'm trying to figure out numerous ways in which to use it...

So far I know I'm going with a 2xAA minimag, the classic option , but I figure I'd try some other hosts for it as well. Basically, I'm unsure what batteries/voltages would work with it.

A mini-mini-mag with a 14500 would be a really neat option, would that work? 3.7v-4.2v is a bit higher then the ~3V from 2xAA or 123. I'd also like to try 2xlithium AA's, this would be ok, correct?

How much voltage/mA could a nexgen 500 w/lux3T take before I'm in the danger zone? I know it says 6V input on the specs page but in actual usage would driving it directly at 6V really be a smart idea? I want to be sure I'm not risking my nexgen's life during my adventures...

The primary limiter to allowable Vin is the Vf of your Luxeon, not the rating of the NexGen board. You can stay completely safe under the Vf of the Luxeon emitter, which is probably somewhere 3.7V-4V. There's a small margin for the losses in the NG, but I don't know a way of finding the threshold besides 1) using a bench supply and some meters or 2) trying a given battery setup and seeing if it blows.

I know that more than a few people here run LuxIII on boost converters with LiOn batteries. It's possible to burn the Lux, but doesn't generally happen in practice.

Do the lithium AA have a nominal voltage of 3V? You don't want to run your Lux on 6V, because it will definitely blow. The NG converter should be okay, though.

The lithium AA have a nominal voltage of about 1.7V, so running 2 of them should be fine.

how about a 14500 battery? Would this be cutting it a bit too close at 3.7 to 4.2v? I could always just let em drain down a bit before using it I'm not running at the just-charged voltage of 4.2v. Again this is all speculation as I don't actually own any of these. Would R123 be ok?

I say go for it, but expect that you may burn out one or more components. I've been running a BB650 Lux3 on a R123 successfully for quite a while now, but a NexGen might fare differently. Also, the Vf of the Lux3 has a ton to do with it. One solution would be to get a high Vf.

J = 3.27 - 3.51
K = 3.51 - 3.75
L = 3.75 - 3.99
M = 3.99 - 4.23
N = 4.23 - 4.47

I would try to find at least M to do this. Of course the downside is the loss of efficiency.

the luxeon I got my sandwich with is one of these:

http://secure3.dnsaction.com/~anlighte/shop/product_info.php?cPath=48_52_29_33&products_id=276

which letter of the part number do those letters refer to? I'm guessing the last letter of the bin code, which would make it an L. Is this correct?

"L" is correct.

Running a K-bin LuxIII on a BB or NG and a single LiOn (14500, R123, Pila) is pretty common practice. I don't remember any posts from anyone complaining that they had burned their Lux doing this. Of course, most people who do this are well aware of the risks involved.

If you want to be 100% safe with a boost converter, you need to keep Vin < Vf. There is a small margin based on losses in the converter. That has been my practice thus far, as I don't have LiOn rechargeables. However, a NG1000 TV1K LE + LiOn is pretty enticing.

The major reason why LiOns work in this grey overdrive area is because they cannot sustain the power (voltage * current) required to burn out the Lux. A fresh LiOn typically starts at 4.2V. At this point, Vin > Vf, the converter runs in direct-drive, and the Lux sucks as much current as it wants (and that the battery can provide) at Vin. I think the starting current is somewhere around 1.2A for K bin, which is higher than rated, but not insanely so. However, this current drain quickly lowers the Vin that the battery is able to provide, dropping the current demanded by the Lux.

Great explanation, for a while I thought that somehow, the NexGen converters had managed to bend the rules. Looks like they haven't.

TY0L Lux3s should be interesting in that case, because L is high enough that even in DD mode it should be more or less OK.

Is there a big difference between using the NG and the BB at 500mA with a TY0L?

So the NG is a straight boost board? It has no buck feature in it? I was kind of hoping it was a buck/boost board. Replacing the Wizards. I'm gathering this is not the case.???

I'm hoping that someone who actually runs one of these setups stops in to comment. I'm nearly positive that my explanation is correct, but it would be nice to get more precise insights.

KevinL, both the BB and NG can be run in this manner (LuxIII + LiOn). I think that the NG's losses are smaller than the BB, reducing the margin: Vin > Vf + Vconvertor. It appears that the NG is clearly better than the BB for LuxIII applications, posting extended runtimes.

ZuluWhiskeyFox, the Wiz2 is the Wizard successor, while the NG is more of a BadBoy successor. The NG doesn't operate above 6V, so it's not a complete replacement for the BB.

err, deleted, already mentioned above...

I'm curious as well if anyone's actually tried the mentioned setups with a nexgen. I do not want to burn out my components...

Yup, that's what I was looking for - trying to justify the price of the NG BB in my mind. $16.50 or even $13 (when they're routinely stocked) for a BB500 vs a $28 NG500 is a little hard to swallow. Is it a LOT more runtime?

It is just like the computer CPU.
The difference in specs may not justify the difference of price.
However, many of us will jump for the newer and better, including me /ubbthreads/images/graemlins/icon15.gif
FYI, the following thread has a graph showing runtimes of BB and Nextgen.
web page
Regards Takifugu

My sandwich arrived here today, I'm impressed, my eyes hurt, I couldn't resist...I ordered 3 optics for it (mcflood, nx05, and fraen) so far the mcflood is my favorite. I'm going to have to find some more hosts now try it out with the rechargables....

btw how do you tell the difference between an nx05 and fraen? I kind of rushed to open them and now I don't know which is which...

Flat top : NX05
Curved top (concave) : Fraen
Hope this will help you identify.
Regards

[ QUOTE ]
Takifugu said:
Flat top : NX05
Curved top (concave) : Fraen
Hope this will help you identify.
Regards

[/ QUOTE ]

thanks, I had a feeling that was the case...

So far I prefer them in this order, mcflood, nx05, fraen. I thought I'd like the fraen the most from what I've read but I guess some people just like a spots more than floods...

[ QUOTE ]
Xero said:
err, deleted, already mentioned above...

I'm curious as well if anyone's actually tried the mentioned setups with a nexgen. I do not want to burn out my components...

[/ QUOTE ]

I use a NG-750 and a NG-1000 with the Pila 150S the Pila 168S and some Sony-17670 Li-ion rech. without problems .

The NG are used in Alephs flashlight and has been tested for 2 weeks .

hello everyone
the nexgen650 sandwich in the shop is TX1J .. will J-bin too low for li-ion ?

I want to cut the AA-minimag to 1AA lenght to run with 14500

[ QUOTE ]
snake said:
hello everyone
the nexgen650 sandwich in the shop is TX1J .. will J-bin too low for li-ion ?

I want to cut the AA-minimag to 1AA lenght to run with 14500

[/ QUOTE ]

Anybody tried J-bin ?