GT mini~reflash the latest firmware~

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.

I said the XHP35 blows the other LED’s out of the water, that does not factor the driver into the equation.

The reason the XHP35 single cell lights underpreform up to now is that they all under-drive the XHP35 by a fair amount. The highest output boost driver I have seen was something like 1.25-1.5A output vs the 2.5-3A we want.

There are drivers in the works that will be able to do this but they are not ready yet.

Can anyone explain why Steel is only getting 3.4 amps from a high drain battery? I would expect more. At least 4.5A.

Is it due to the super long LED wires he’s using to test with?

Yes, those wires will cause a massive voltage drop and thus current drop.

Okay, that’s good to hear.

Were you able to do a tail cap amp draw test to see what it does in the light?

With a FET, it could exceed the 1200 lumen and throw specs.

Thanks for the great pictures steel_1024, well done!! (as usual :wink: ) :+1:

Thank you for reviewing… Sharp Pics btw… :sunglasses:

I can get some readings but I swapped the LED in mine to a NW LED so it would not necessarily match what would be seen in the production version since the Vf varies among the LED’s.

If people really want to see I can check though.

I did test the lumen output before I swapped the LED and with the new TA sphere it read a bit over 1200 lumens.

Hmmm, it’s good it does hit the spec’d lumens, not everyone can say that. :wink:

I guess I was hoping for a bit over spec since it’s FET. Maybe 6A and 1400 lumen. :smiley:

IDK, that might be pushing things. I guess spring bypasses can still be done.

PS, I just noticed they raised the lumen spec from 1200 to 1250.

Yeah, I read 1250 lumens on my sample so I guess they are using that number now.

Spring bypasses would net you a bump in performance but ~1300-1400 lumens is about the most an XP-L HI can do in my experience.

Any links to the GTmini sourcecode and hexfile.

Steel, I just noticed you reflashed it to NarsilM v1.2

The manual says it’s supposed to come with v1.3.

Did your early production model have a bug in it or something?

I know where NarsilM v1.2 is, but v1.3 is harder to find. I think Texas_Ace has it. Do you know him?

His prototype had the thermal regulation set to off by default. It could of been changed in the menu as well but re-flashing ensured it was like the production lights will be.