I’m in for one piece of this great flashlight!
+1,000,000 
Good news, DEL made the first driver prototype
It works at 2,24A with good 90+% efficiency
Parasitic drain is acceptable at 156uA and possibly a bit lower.
Wow this is pretty freak’n awesomely excellent !!! 
Great work DEL!!! :+1:
Man , i can’t wait to get one 
As The Miller mentioned, the prototype driver is built and mostly tested. It is running a tweaked version of Tom’s NarsilM and it has been performing pretty well.
Some numbers:
- Switching frequency is at 800 kHz with the selected components and at 16.8 V input.
- 100% output is 2.25 A, but this easily adjusted by changing Rsense. Aim is to have >= 2.5 A stock.
- Everything is running cool. ‘Hottest’ components are the buck chip and 100 mohm sense resistor, and both have a Trise of barely 20 C.
- Efficiency is 91% at 16.8 V, peaking at around 93% as the battery voltage approaches the output voltage.
- With my ‘LED load’ (4 x 3 V emitters on a beefy heat sink), it stays in regulation down to about 13.8 V (3.45 V per cell). An actual XHP35 should do better.
- As the battery drains further the LED current fades gracefully. About 2 A left at 13 V, 0.8 A at 12 V.
- Parasitic drain is 156 uA. The bulk of this is the buck chip, unfortunately. Will bring it down to about 125 uA by upping the LVP resistors.
- The firmware has been set to get pure analog dimming between 100% and 20. From there it is further dimmed using 15.6 kHz PWM. Butter-smooth Narsil ramping! (The 20 analog dimming limit is not set in stone, but some efficiency is sacrificed if trying to go much lower.)
- Getting a moon mode of 0.44 mA, using a combination of analog and PWM dimming.
Beautiful, DEL. Do you think a lot of efficiency will be lost by pushing the components to 2.5A? What about longevity?
Is it just me, or did the project get a much faster pace in the last few weeks?
Orsm work DEL. :+1:
That is one nice looking driver
That’s a beauty DEL, remarkable work! 
The heat form this driver should be a non issue in the massive light! :+1:
hey im interested, can you put me down for one.
dont want to sound impatient but how long before its going to be available. Or even see a working prototype to be able to get real world figures and outputs from?
I wish there was a buck driver like this that could do 12A+ 
NICE DEL!
beautifull driver for sure!
And awesome how you write stuff like: “but this easily adjusted by changing Rsense” and “Will bring it down to about 125 uA by upping the LVP resistors.” it’s like magic and you’re a grand wizard for sure!
Will update list later
Thanks for the kind words everyone!
Regarding capacity, the design is very conservative and it should be able to run 5 A with minor modifications. Doing that will have some components run pretty hot though.
2.5 A is only a 10% bump from where we are now and is not an issue. Only reason I am at 2.25 A is the availability of good current sense resistors. Would have been nice to stick with 0.1 ohm.
Very nice driver setup there. Only thing I could see to improve it would be a 1617 mcu.
+1
I will start a NarsilM thread soon. Might not have DEL's buck driver mods in it for the first release but that's the plan. Hoping it will be just another compiler switch in the setups header to choose between 1, 2 or 3 channels or buck.
Please put me down for 4 more for a total of 5. Saw there was a limit of 555 but put me in line for the spaces opened up by those that drop out. Thanks
Don’t think it’s fair that Lumintop is limiting the number we can purchase. They are getting tons of free R&D, design, and testing for nothing and then want to limit the amount we can buy before the price increases by a significant amount. It might bite them in the butt like what happened with the Kronos lights. They ended up selling for less after the group buy than they did during the group buy. Labeled Astrolux of course.
It is fair for this is not shaping up to be a light costing only half of the groupbuy price to make thus leaving such a big margin that after groupbuy prices can be lower.
I really don’t want to go into how and what Kronos did, just know we do everything possible to get a really low price on the projects I am involved in.
Maybe maybe if the reflector costs are good and the overall costs of making a GT and shipping it are lower then expected we can lift the limited amount for the groupbuy or make the number for the groupbuy higher. IF this is the case, it will be communicated and changes to the lists will be made accordingly.
I’m in for one piece, I hope it’s not to late
…and how much is the blinking frequency of the strobe mode?