I guess I kind of worded that wrong. I know the interest is there, it has been for a long time.
Maybe like a pre-order thread. “If I produce this driver who would be interested and how many” thread.
Loneoceans was saying once his order hit 1000 that the price would probably decrease per board.
I’m thinking 1000 would probably be gone pretty quick and its possible that 1000 could be sold on a pre-order.
Depends on a few variables with the specs of the driver or if another enters the market at the same time.
I myself would buy 5 to 10 boards depending on specs and price. 200 flashaholics buying 5 boards each equals 1000 boards.
moderator007
You can check demand in Lexel’s thread. 1000pcs groupbuy will take years. Custom driver cant be more popular than Q8, for example (how much time it take to reach 1000pcs for Q8?).
Anyone have experience with ordering cnc-mount pcbs? MOQ can be even more than 1000pcs.
There are a few other options that could possibly see them produced as well depending on how things go. Once loneocens is happy with the design and gives a “final release” we can discuss getting them made. From experience it is best to wait until the driver is done before talking about this type of thing though.
I went back and read through this thread. Looked on loneoceans site. Read the dataSheet for the ic. Well looks like the driver can only be used with a led at or above 6 volts vf or series leds. I had thought this would run a single led (such as a xpl) at a constant current through the entire run time until a single cell was depleted.I know see that the led must have a vf of 6v or more to work. So while there is interest still there for this driver, it is limited from its output voltage.
Loneoceans have you tried to see how low the output voltage can actually go.
A boost driver can only increase voltage above that of the input voltage. So if you input 4V, then then lowest it can possibly go is 4V.
A buck driver would be needed for an XP-L, although it would fall out of regulation fairly quickly with only one cell.
So what is actually needed is a more advanced buck/boost driver. These are hard to come by and would be very challenging to fit on a driver this size.
A 30q cell can only do 4v for seconds at 5 amp load. At 4v a xpl v6 would see 5 amps, nothing crazy. So if a boost driver was set at 5 amps output it would run direct drive for maybe a few minute and hit the vf of the xpl at 5 amps and then switch to boost through almost the entire discharge, at least theoretically speaking.A xpl v6 needs 3.8v to run at 5 amps according to djozz’s graph. Cree XP-L V6 2C led, tested against XM-L2 T6 3C, edit23/7: I repeated the test and measured a dedomed XP-L
Fet and amc7135 drivers would fall out of regulation about 1/3 the way through at this current and reduce current as the battery voltage decreases. Probably to much for a xpl2, but a xpl or xml should be fine.
A 30q cell can only do 4v for seconds at 5 amp load. At 4v a xpl v6 would see 5 amps, nothing crazy. So if a boost driver was set at 5 amps output it would run direct drive for maybe a few minute and hit the vf of the xpl at 5 amps and then switch to boost through almost the entire discharge, at least theoretically speaking.A xpl v6 needs 3.8v to run at 5 amps according to djozz’s graph. Cree XP-L V6 2C led, tested against XM-L2 T6 3C, edit23/7: I repeated the test and measured a dedomed XP-L
Fet and amc7135 drivers would fall out of regulation about 1/3 the way through at this current and reduce current as the battery voltage decreases. Probably to much for a xpl2, but a xpl or xml should be fine.
But I’m with yeah, a buck boost driver would work best and fit more applications.
I believe Lexels upcoming Boost driver will handle the larger sizes. I think his will be 20mm and up IIRC.
What really makes the GXB172 unique is its small size.
I remember reading somewhere that Lexel had Bistro HD OTSM (or some version of Bistro) that could work on both switch types.
Hopefully Lexel can confirm both my statements.
Thanks for your kind words! I’m really not worried about making the driver for mass production. It’s a really a fairly simple process (other than the costs!) and I have a fair bit of experience sending out for assembly from 10 boards to tens of thousands. As it stands I can just send the package I have generated to a fab house, throw money at them, and get a box of assembled drivers with no additional work on my part. What I’m more concerned about is having a product for sale which is buggy or unsafe! Though if people don’t want to wait and prefer something which may have some quirks, don't mind paying for it, update the firmware in the future, or run the risk that the driver may have some issues, that’s OK as well. As a result, right now I’m just focusing on development and testing instead of for production.
It’s one thing to produce a driver that works (it’s working decently well now!), but another thing to make one that covers end cases, and safety (especially for one with such a large power capability). It also takes effort to have most bugs ironed out, and to have one that supports the firmware that people want. Thanks for your understanding everyone! Meanwhile if work still needs to be done on the firmware, I will be releasing all the hardware details so people can make their own first (or do a small batch order of the preliminary hardware) with the basic firmware I have right now. Many possible options!
Yes it’s great that there are lots of other drivers in progress so we’ll see how they go! As mentioned I did not start this project with any intention of making money out of it and anyone will be free to make their own. That said I’m hoping to get it to a state where I can get a batch of them made and have them distributed. More work needs to be done on the firmware (in progress), since stock firmware will have limited efficacy on any driver with similar topology. As a side note, Arduino is great! Helps in portability among different controllers, and it’s really no different from existing BLF firmware (which can be complied in Arduino, and likewise Arduino sketches can be complied with Atmel Studio as well. :) They’re one and the same thing, just with a different cosmetic wrapper.
Thanks for the kind comments! Is it possible, yep definitely. However again I’m not quite sure if it falls within the scope of this particular project, and it will certainly need more parts, and likely a slightly larger board area. :) So perhaps for a subsidiary project! Otherwise, pretty easy to implement.
Yes this is meant to be primarily a single cell boost driver, specifically for 6V LEDs or 12V LEDs, or for some people, 9V for 3S LEDs. As mentioned it can also work with 2S with 12V LEDs, but it is not a buck boost, and cannot do any sort of buck functionality, and was never designed to do so. If there is interest in a general purpose high power buck boost, that’s a separate (and fun!) topic! Not too hard to make a decent 5A driver too. Unfortunately I have limited time and I can't do so many things at once!
How’s Lexel’s driver doing? I originally though Schoki’s and Lexel’s driver were the same but turns out that they both have separate drivers. If Lexel can get a working driver out in production first, that's great and everyone should buy his driver! Like I said I'm not in this to make money, just working on this because I thought it would be an interesting EE project, and since there's interest, I'm working to try to make it better so more people can use it. Answering Agro’s questions, for 17mm, it’s easy to swap out the inductor for the smaller 3mm tall one, just with a little cost in efficiency and thermals, but will work just fine. Obviously the larger inductor will be better 
. I have basically no experience with other flashlights though so I'll be very happy to learn more about other popular 17mm and 20mm driver hosts and their physical constraints.
For sizes, I’m also working on a 20mm version because I need some for my SK98 hosts! Also 20mm allows me to make some significant layout improvements, instead of just naively expanding the ring size. However I have no current plans to make larger versions yet. The reason is because any larger board will allow me to move to an external-switching-fet(s) architecture, allowing for even better performance and cost compared to the GXB172 architecture. As a result, there’s really no reason nor difficulty in making a larger one. For example, if I had to make a 30mm driver board, I could go all the way to a 100W driver. So it’s outside the scope of this project series. Sure I could just expand the ring, or move components around keeping the schematic the same, but it's really not the ethos of the project, and since the source is available, anyone could build different version of their own.
For firmware, I’m working to incorporate Bistro and Narsil into the driver. Porting code across appropriate controllers is easy. Porting it to work with this particular architecture will take a little more time since there are particularities which need to be handled. Full feature testing will also need a little more work, and some features may not be applicable with a driver of this power density. Likewise some new features will also be added. But once the hardware is ironed out, the firmware follows separately but in parallel.
Want single cell MT-G2 flood monster!
Lexels boost driver will be available for purchase soon. Keep in mind that it will be 20mm and up in size (I think).
Looking forward to see Lexel's driver in action soon :) The GBX172 will also have a 20mm variant with even more features (under testing now). For >>20mm variants, as mentioned in my previous post there is no plan for any driver with the same topology, since a large board space will allow the use of discrete components, and should be pretty easy to make a 100W or higher driver, though again thermals will be interesting to deal with ^_^.
Just replied to your email and then saw this. Definitely interested in the 20mm. The GXB202?
- Clemence
20mm is too large to fit inside the S2 but upon more thinking I’m not sure what kind of reflector or optic could be used with S2 and MT-G2 combo.
Keep in mind the loneoceans is not going to offer his 17mm for sale. He shows the plans then you have to build it yourself. That’s why I mentioned Lexel. He will be building and selling them, but not a boost driver in 17mm.
I wonder if the Convoy M1 or M2 might fit a 20mm driver. It’s head is a little bigger plus it has a bigger reflector which might work better with the big MTG2. Research would need to be done.
Hm that's not what I said :). I said I didn't design the driver with the goal of selling and making money off them. If the driver turns out successful, probably will find a way to get a batch fabricated and assembled. ^_^. But if lexel or anyone else gets a working driver for sale, that's fantastic! Always better to have more drivers :)
My bad.
I hope Lexel or someone is able to offer it.
Hello all,
Alright more updates..
TL;DR: GXB172 works great for XHP35 (HI), driving it at 2.5A 14.7V. Power source was a single LG HG2 18650.
I finally got my hands on an XHP35 LED on a MCPCB (from Kaidomain), so I could do some real life testing of the GXB172 driver on 12V (4S die) LEDs. The candidate of choice for this test was a XHP35 HI, 3000K, C2 30G 80CRI LED. The light was mounted on a medium sized heatsink for testing and connected to my GXB172 in 12V mode.
For this test, the goal was to run the XHP35 HI at it's maximum output (before output starts to suffer).
I referred to Texas_Ace's excellent experiment here: https://budgetlightforum.com/t/-/43473. From this, I determined that 2.5A was the maximum one would want to drive an XHP35, after which you get no additional lumens and run the risk of damaging the LED.
Soldered up an XHP35 and connected it to my GXB172 dev platform... and turned it on.
... and... it works!
Note that based on my previous work with putting together an actual 17mm driver, the 17mm PCB performs at least as well as, if not a little better than my 'dev board'!
So I fully expect the GXB172 to work just as well, in the form-factor PCB.
Test was conducted at a variety of power levels all the way from the lowest setting (about 2-3mA @10.2V) to the LED, all the way up to 2.50A at 14.70V (36.75W to the LED). Battery input was measured at just over 40W, so about 90% total efficiency (including wires etc, probably a little better in a well-put-together flashlight), with higher efficiency (>95%) at more realistic power levels.
I plan to have this LED put into one of my old SK98 hosts since that has a zoomy lens. This should make for a pretty nice 'budget' throwy light, and pair nicely with my 144 Convoy S2 'floody' light!
So stay tuned for a 20mm version (since that needs a 20mm driver).
Thanks for following this project and as always, more to come soon !
Very nice! I have wanted an xhp35 HI in an EDC for a long time.
Hmm, now I start wondering how much power it can put out for a triple xhp35……
I know, I know. Never satisfied.
What. You want to put it in a Sofirn C8F? Lol