GT mini~reflash the latest firmware~

well done my friend!

Very nice! Thank you for the glimpse at the driver. :+1:

Nice!
Is it hard to get the driver out? How much glue?

My GT mini has no glue.

The driver must be pressed with the barrel.

Replace the battery from the rear.

Sorry but FET+1 driver ?! I thought Lumintop went for a regulated 4,5A buck driver ?

Yeah, came here to ask this question. The manual that was published indicated a regulated buck driver. I know at least one person who was interested in the light in part because they wanted to swap in a de-domed Nichia 219D. The low V_f of the 219D would play very nicely with a buck driver, but not with a FET+1. Not only that, but a FET+1 kinda seems boring at this point, making it too similar to the Emisar D1S and Astrolux C8. A well-designed buck driver would have been a nice differentiating feature in a rather crowded category.

Also wondering about the driver change from the manual…

you can read the latest documents here:
GTmini user manual & NarsilM CheatSheet GTmini

i try to find out why a "buck driver" is mentioned in the manual

So which is it?

Is yours a special preproduction unit? You always get things before everyone else. I’m hoping there’s no glue for the shipping version too.

Thanks for the great photos as usual!

Because its an error in the manual.

nice to see the actual flash process, thanks for the steps/pictures.

The driver is a FET+1 design. A buck driver was considered but it would limit the output greatly with the XP-L HI LED.

I have yet to see a China buck driver for a single cell light that was in regulation for more then a few minutes. Usually they drop out of regulation almost instantly. Rendering the entire point of a buck drive moot except for low modes.

The manual was copied from the normal GT and the buck part just slipped through and was not put in there intensionally.

Yeah; a buck would really limit it with the high vf of the xpl hi, but it was the only real reason for me to get this light: the potential to soon put something with a Vf too low for a fet+1. If it’s going to be so similar to the d1s, I’d rather go with that. Besides, I have a thing about when, after lots of people’s money has already changed hands, things turn out to not be as they were described. (In the manual, in this case.)

Of course almost all buck drivers fail to regulate using only an 18650 at turbo outputs for more than a few minutes, especially with an XPL HI.

To maximize runtime with buck drivers, you need to either bypass the spring/use a copper alloy spring, use a high drain high capacity battery such as a 30Q, minimize voltage drops in the buck driver itself, and etc.

An XPL2 HI would also help. Or maybe a E21A.

TLDR: Unless you go with a 2S setup, maximizing buck driver efficiency and voltage delta is crucial.

If performance on turbo was all that mattered, almost no one would care at all about regulated drivers in 1s lights.

And yet, some guy, goes by the username Texas_Ace, created a really nice family of drivers with two channels of (linear)regulation and turbo.

Is this the first time this has been shared publicly?

Thanks for the review and update steel. :beer:

lol, very true.

I was not involved in the mini-GT project until it was basically finished. All I had a say in was the firmware basically. I gave a few suggestions early on but most of them were not used.

I honestly have not followed this light almost at all, been too focused on the Giggle Monster and some other lights to think about this one since I did not have much say in it to start. So I am not sure what has been posted before.

I was asked in a message what driver it had and confirmed it was an FET driver.

All of that said, I do feel that an FET driver makes the most sense all things considered for this light. A buck is nice and if it was going to come from the factory with a low Vf emitter then I would say a buck could make sense (although regulated runtime at turbo would still be quite short) but with the XP-L HI I see no use for a buck driver in this light.

Also I have learned a lot the last few years about driver efficiency and things are not nearly as bad as we once thought with a PWM FET + N driver.

Throwers are not generally used at low modes so the only advantage a buck driver would have (slightly longer battery life at lower outputs) is rendered almost moot.

The real future of flashlight drivers are boost drivers IMHO. The XHP series of LED’s blow basically any 3V LED away in performance.

Naturally it is up to each person if they still want the light with an FET driver. Be aware though that with the stock setup (which is all that really matters to lumintop understandably) it would reduce the peak output by a significant amount.

Ehh… not so much for compact throwers, I think. The XHP35 HI does well with multiple 18650s and a huge reflector, but lights with only one Li-ion cell and a boost driver rarely make their advertised numbers with the XHP35. I don’t know of anything using the XHP35 HI that’s the size of a C8 and throws farther than a FET+XP-L HI C8, for example. Do you?

Note that advertising more throw is insufficient to satisfy my query; someone whose incentives align with the community more than the manufacturer must supply the numbers.