[PART 1] Official BLF GT Group Buy thread. Group buy officially closed! Lights shipping.

welcome and your are on it :wink:

Ah, gotcha. I thought they could be wired 6v or 12v like the rest of the XHP line but had forgotten that they’re different. Then the discussion happened about modding for 12v XHP70 and I lost track of what was being modded. My fault.

Gah, thanks. I shoulda thought to check the first post before asking. Great design, basically with a “filler” piece built in.

Thank you sir! I’m excited about this one!!

and thanks to you, hahoo, for looking out for me :slight_smile:

emarkd, not everyone thinks of everything. BTDT myself.

I’d be curious to know what the throw on a modded GT would be like with the other LED and goosed amps. I remember reading somewhere here that basically the light output has to be hugely more to gain a bit of throw. At least that’s what I got from it. It would be nice for giggles, but I’m thinking not so efficient. (Since when did we care about efficiency though?) But Narsil would allow for less amperage to the LED to regain efficiency, correct?

it is my understanding that for a driver like this amps are kind of hard.
So besides 2.5A being the sweet spot for max output more amps at 12V reliable would mean different components, higher costs
It is interesting, for what I understood from TAs many post about series is that high amps are harder then higher voltage, would this be why so many single cell XPH35hi lights have made it to market at a relative low cost?

Correct, buck drivers (and electrical components in general) have a much harder time dealing with amps then voltage.

Voltage can be scaled up with virtually no change in component tolerances or loses. The only real limit with voltage is keeping it from arcing or sparking. So the components needs to be rated for the voltage but it is a fairly simple task, you just add space between the traces or insulation to keep the voltage from arcing across and shorting something out.

Current on the other hand you can not escape, the only way to deal with more current is with larger, beefier, better components. This means more raw materials to make the components, more shipping costs ect.

The end result is that as current goes up, so does price, weight and size.

5A @ 12V is 60W of power, which is plenty for any LED on the market right now, sure an xhp70 might gain a little pushing it harder but not enough to really matter. People can get custom drivers for more extreme setups then that.

Regarding an XHP70.2 in this light: people are reporting ~180Kcd in the smooth L6 reflector. If the L6 reflector has an active diameter of ~66mm, then the 120mm diameter GT reflector has ~3.3x more area, leading to around 594Kcd. That is driven at a very high current though.

OK
TN42 on highest
28°C outside no wind
After 6m22s the part with switch and driver is hot
I still can touch it but not comfortable.

The tube gets warmer and the head too but slower then the tube

10m49s
Switch driver part is hot
Uncomfortable hot
Head lags behind
Battery tube hot but less then the hottest parts at 6.22

13m40s
I stop for the hottest parts are not nice to hold and I don’t want to heat it up too much
Ah what the heck ok after a minute cool down back to highest
Two minutes in, again driver and switch area not burning hot but too hot to comfortable touch
Placed it on a bench so no heat can escape via my hand

4m30s head is hot, tube is hot. Only driver/switch area feels burning hit but I can keep my hands on it without actually burning so it is between 50°C and 55°C

5m58s
Driver/switch area seems stable, head and tube still rising. (So we are ~20 minutes in on freshly charged Panasonic protected 3400 cells.

8m40s
The tube and head feel like when I stopped the first time.
After a couple of seconds I can’t hold the driver/switch area, it still rises in temp.

10m42s
Tube can be held without tendency to grip with one finger and switch fingers to give the heat no chance of giving a burning sensation.
Head, no more then 4 seconds in firm grip, gotta let go then, max 2 seconds for driver/switch parts

14m30s
Tube is getting too hot to firmly grip
No equilibrium
Almost half an hour in
Was I walking a little breeze would have cooled it, was it cooler or was there a little wind, that would have helped
Would I have held it, my hand could have taken away heat.

Turning off at 16m30s
Cells feel warm, lol tricky to unscrew the tube
Carrier is warmer

So half an hour in not ideal situation for cooling
Yes the GT should do better but we can up the default thermal stepdown for it for sure :wink:

Five minutes later, all can be touched normally but is still warm to hot
Wow I am happy with the deep fins at the hottest parts of the GT!

EDIT voltage cells 3.81
walked with it on med for a few minutes too
starting voltage 4.19
pretty decent I think

Now you understand why I was so keen on max cooling for the GT with it’s “low output”. There is no such thing as too much cooling. lol

Also around here the outside temps can easily be 90-95f at night (last night it was around 93 till midnight). So it would heat up even more.

that hahoo sounds like a nice guy :wink:

Yeah no doubt. I wonder who he is?

in for 1

Must be Tom Hanks ! :sunglasses:

haha! would be nice…my bank account would have a few more zeros in it for sure :+1:

Is that your name here buddy? Really appreciate you looking out for me like you did… you’re a true gentleman! That goes for everyone else who tried to help too. nobones, eek… y’all know who you are! :slight_smile:

Btw I did finally receive a few texts from saabluster this week. He didn’t offer any timetable for my Deft-X mega upgrade though…. we just talked about life and stuff. :person_facepalming:

anytime my friend… :+1:
this light should be epic, would of hated to see you miss out :wink:

If it’s possible I like to have one, too.

Even if its not that useful I really want this flashlight. Its big, ugly, heavy and everyone will ask about it and thats perfect :smiley: .

I don’t know about ugly, but I’m definitely chuckling!

It’ll look like a normal size light in the hands of a really massive person. Slung on me it’ll look like exactly what it is, a huge light. Yes, it will definitely get comments.

I’d like to see an extended Q8ish 8 cell light for massively extended runtime if it could be done. It would be the power outage light to beat! Of course it would need to be easily slung.

Just registered for this, you can put me down for one GT too.