IMRbatteries.com still has the button top LG HE-4 on sale for $3.50 each. They also have a wide selection of cells at or under $4.00 each. With many top cells even at $5.00.
Ok ! I thought as a buck driver it would act differently (than fet drivers) , thanks for explaining .
4S 18650’s yield 16.8V when charged, so meeting the simple needs of a 12V emitter like the XHP-35 at 2.5A is easily met by virtually any 18650. Especially if using 8 instead of 4.
To meet the needs of 2.5A, even up to 3A, I looked briefly through HKJ’s charts and find virtually every cell I looked at exceeds 3.3V until way out at the end of capacity. I’m having some physical issues at the moment so I didn’t delve into it deeply, but picking what I thought to be the worst cells shows a random bunch of the low end cells easily still do 3.3V way out to end of charge.
I said they’d work, I didn’t say they’d work better or equal to top name cells. Any 4 matched cells will run the GT pretty well, for top performance, you gotta pay to play. 
Well, it's actually over 13V according to DEL, and there was resistances with the carrier that add up, so it's not so easy. It wasn't anticipated it was so high. Could it be the specific XHP35 HI DEL had to test with? Yes - could be, we don't know. DEL himself was surprised.
Yes, it does act differently. It does true regulation like any buck driver as long as the voltage you get from the cells after loss's is at or over what you need -- that's the issue.
Playing Devil’s advocate, here’s a look at actual emitter values in a Shooter 2X with Neven’s LD-2 driver to an XHP-35 HI
0.06A at 10.80V for ~89 lumens
0.55A at 12.22V for ~783 lumens
2.87A at 14.75V for ~2346 lumens
So if the GT were to push 2.87A, which it’s not set up to do, a cell that could stay at that amperage to 3.6V would stay in regulation. This will obviously be lower in a light that has a max capped at 2.5A. If using a lesser cell, simply stay within the ramping confinements, as long as you’re not double clicking for Turbo you’d be fine with any cell out there. Double clicking for Turbo will still work, just not as long or efficiently as a top cell could provide.
Ok, but that's theoretical with no voltage loss's, and, forgot to mention: no driver efficiency loss as well.
And Steve's test results pretty much prove it can't get enough voltage out of 4 cells to keep it in regulation, unless we drop the amps from 2.5A to 2.0A, but with the prototype design and carrier of course.
I wish one of us had an 8 cell prototype to test this all out with. Right now I think DEL is on a long biz road trip though - he would be a big help here. I'm not sure if TA did any tests like Steve's, or if anyone determined where the voltage drops come from that add up, etc. The buck driver is supposed to be pretty efficient.
The testing/analysis might have happened and I missed it, dunno.
Sure would be nice to see some actual test data and specs from Lumintop one of these days?
Specially with the batteries they recommend……
Yeah KW, we asked today if they have test results, gonna post when we hear back on it 
I want one please add me
Put me down for one (1) please.
OK, so here’s to hoping this is a ways off still (for budgetary purposes) :money_mouth_face: This thing is a beast!
I wonder if there is a way to put a usb-c charge port into the cell carriers?
It’d be complicated to do a charging port due to the 4 series arrangement.
It would be pretty useful/cool though…
I just read the first post and realized this project has been going on for about a year. If I’m not mistaken, this was before the TN42 was released. So now the TN42 is out and it is the benchmark to beat. If this takes too long, there will be something better coming out. Hopefully this doesn’t become a cat and mouse game trying to catch up. Kind of like waiting for the next phone “because it’ll be better than the one just released”.
Only if you want the longest thrower, if you want that just mod the GT with An XP-G3 and push it to its limits, did someone say light saber
How ever I prefer to be able to see what I am looking at without using a spotting scope
Cheers David
The TN42 was out before this project started.
The GT is getting close to 1.3Mcd in tests, which is significantly more than the TN42’s 700-800kcd.
There is always going to be something better, but the GT probably won’t be passed for a while (as reflector+led type), at least several years, because it’s unlikely that manufacturers will want to build a light this large or larger.
Thanks for correcting me. I wasn’t sure if the TN42 had been released by then.
Hopefully you’re right about the last part. This could be like a Convoy, ready for upgrading in the future when a better LED comes out. This housing’s gotta be reusable because of its size!
It has been designed with upgrading and modding in mind, yes.
There already are people planning to mod this light for 2-3Mcd
I was curious, does the GT have a lighted side switch? I didn’t see it in the video and the switch cover is pretty dark. I’m guessing no, but was wondering since the Q8 had one.
The switch in the prototype looks dark with a chromed ring.
Pommie (David) I could not agree more. This is not only an exceptional thrower by any measure, but the amount of light on target is way more than xpg2 or xpl hi. Nice to know you don’t have to have a snipers spotting scope to see the area illuminated down range. The xhp 35 hi, for me, is the best available emitter option by far, the beautiful tint is just icing on the cake.