# b3flex



## georges80 (Jan 5, 2010)

Hi Folks,
I know a lot of you have been waiting for more stock of the b2flex to arrive. Anyhow, the reason for the delay is that I have being putting off doing a new run. Over the past two months I've been working on a new design, obviously not full time, since I was also on holidays in Oz.

I get emails every so often asking about modifying the b2flex to run 2A etc, well, it can't be done. The switcher IC on the b2flex is limited to 1.5A output.

So, I've been looking into other options to crank the output higher and have spent quite a bit of time going through various prototypes to see what I could do. Here's Rev 1 and Rev 2 of the b3flex:

On Rev1 I stole the switcher IC to use on Rev 2. Top view










And bottom view:










Same size as the b2flex. Unfortunately no luck. First Rev had a brain glitch on my behalf so it was pretty well a waste of time (other than creating a boost driver...). Rev 2 showed that the switcher IC I had chosen, while having a great internal switch had some pretty awful quiescent current draw. So, even though it worked, for a driver that can be dimmed it just wasn't acceptable.

So, I'm now onto Rev 3. I have the proto board on hand, but am waiting for a few parts to arrive early next week. This new design is based on the h6cc/h6flex core (nearly identical other than sizing down some of the component current capabilities to shrink the size down to 1" diameter and components on both sides). I'm pretty confident that Rev 3 should work given its parental heritage.

As with the b2flex, the b3flex has an area on the PCB that will be the thermal attachment point to a headsink.

Anyhow, I'll keep you updated via this thread and post up pics of Rev 3 soon. Oh, and yes, the target for the b3flex is to provide current tables up to 3A, minimum operating voltage will be 6V.

cheers,
george.


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## cytoe (Jan 20, 2004)

wow. I'm drooling on my keyboard. Nice work George.


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## mattthemuppet (Jul 16, 2004)

woohoo! I was wondering how this was coming along. It's going to be very hard to resist the urge to upgrade my helmet light with one of these, possibly even with a "first time trying a lathe" housing too. Hopefully, it'll take you several months to finish, so I can finish other jobs and start work on persuading the wife of it's merits


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## JezV (Oct 31, 2009)

Nice one George! I really like my old bFlex but 1000mA is _sooo _2009! A 3A buck driver in a smallish package is just the job for 2012.


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## Ofroad'bent (Jul 10, 2010)

Will this thing run 1 XM-L off 7.2v, or is it more for triple XP-Gs and the like?


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## georges80 (Jan 5, 2010)

Ofroad'bent said:


> Will this thing run 1 XM-L off 7.2v, or is it more for triple XP-Gs and the like?


6V min input, max 3A output. So, 1 LED running at 3A from 7.2V isn't an issue. The b3flex, like the b2flex is a buck driver, just with increased output capability (with more current tables).

cheers,
george.


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## Toaster79 (Apr 5, 2010)

Keep 'em coming George!


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## brad72 (Jun 12, 2009)

Lovely George. I am always impressed by your electronic prowess.


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## Ofroad'bent (Jul 10, 2010)

georges80 said:


> 6V min input, max 3A output. So, 1 LED running at 3A from 7.2V isn't an issue. The b3flex, like the b2flex is a buck driver, just with increased output capability (with more current tables).
> 
> cheers,
> george.


Excellent! I note you're hoping to get it around 1" diameter. Any chance of it being a touch smaller, say 22-24mm? Hard to tell in the photos.

Your drivers are always a pleasure to use. Keep up the great work!


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## georges80 (Jan 5, 2010)

Board diameter will be 1". It's not a hope, it must be 1" in diameter since it is meant to supersede the bflex/b2flex and there are customers that have based their designs/housings on that form factor.

Making the board smaller is not viable, considering it will be operating at up to 3A and capable of driving multiple LEDs. There are power losses that needs to be dissipated and there's a lot of connection points on the periphery that all take up valuable room.

I'll post up pictures of the top/bottom of the bare V3 proto later, there's not much free room....

cheers,
george.


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## georges80 (Jan 5, 2010)

Here's top/bottom pics of the b3flex V3 proto - obviously without components yet. I'll post up an assembled pic sometime this coming week when the rest of the parts turn up.










Basically a top (left) and bottom (right) view of the board.

The reason for the largish area on the left side of the bottom of the board is for mounting to a heatsink. The heatsink should be attached to cover the 12 vias that are in a chevron like bunch AND include the isolated island just below them (which is the thermal path for the power FET). Once production boards are complete then I'll document the region properly on my website.

So, you can see that the board is quite busy. Consider that the left side of the top of the board also has a honking big inductor that is square in shape.

Oh, and to bring it home a bit more, here's a screen grab from the cad layout software. The top stuff is the dark grey and the light grey is stuff from the bottom side 'peeking through'.










Just in case it isn't obvious, the production boards will of course have full solder mask and silkscreening. These pictures are of the bare prototypes that I run to test various designs. I can get boards back quicker and for less cost and put several designs on one panel by going with a 'bare' process. These are cut from a larger panel that I run through the PCB house - hence the rough cut/sand edges and the annular ring of copper on the top side - I put that on the layout as a 'cutting/sanding mark' and in this case is exactly at 1" diameter.

Hopefully this 'behind the scenes' stuff is of interest to some of you folk and provides some background of how much work goes into a TaskLED driver before it becomes a production board.

cheers,
george.


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## Ofroad'bent (Jul 10, 2010)

We sure appreciate all the work that goes into them.
I've got at least 20 of your drivers in various lights for myself and friends, both homebuilds and Night Lightning lights.


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## brad72 (Jun 12, 2009)

Fantastic work George. I've just started to make SMT boards and I have to admit it is quite an art/skill going from the schematic to rats nest to a finished populated board so I truly respect the work that goes into your drivers. Writing the code, well that's an even steeper learning curve. 

Keep up the good work


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## BrianMc (Jan 5, 2010)

Nice update. I love the UI flexibility. 3 A max opens up the options. 

BrianMc


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## [jsl] (Sep 20, 2007)

This is excellent news!


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## Praxis (Apr 30, 2007)

It's nice to be able to share my excitement with like-minded individuals (nobody else understands...). I can't wait!

From what I can tell, the components are of course now different to handle the increased current. I understand the diameter will stay the same, but how about the thickness?


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## brad72 (Jun 12, 2009)

Praxis said:


> It's nice to be able to share my excitement with like-minded individuals (nobody else understands...).


I totally agree. The other day I was talking to my wife for 10 minutes about the ashperic light I am building and when I stopped to hear her response she said "oh i'm sorry, did you say something" (she was watching tv). Like a 40 year old man child and sulked off to my shed to talk to my imaginary shed friends.


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## mattthemuppet (Jul 16, 2004)

brad72 said:


> I totally agree. The other day I was talking to my wife for 10 minutes about the ashperic light I am building and when I stopped to hear her response she said "oh i'm sorry, did you say something" (she was watching tv). Like a 40 year old man child and sulked off to my shed to talk to my imaginary shed friends.


I can never quite tell if my wife is humouring me or genuinely interested in situations like that - hopefully the latter most of the time.


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## georges80 (Jan 5, 2010)

Finally received the parts I was waiting for a few days back. Got some time today to solder up the parts on the proto, build a programming jig and download the h6flex version of the firmware just for testing purposes.

A few little tweaks to some components (I had values from the previous revs in a couple of spots on the new schematics - my bad....) and the board appears to be operational and working on the first current table, Albeit at strange current levels since the current tables need to be adjusted for the 3A component values of the b3flex.

So, here's some pictures of the assembled first prototype.










and the other side with the programming jig next to the board










and the other side zoomed in a bit. The red area is where the heatsink path needs to be attached for higher output currents. I'm expecting that the board will behave like the b2flex thermally, so for currents below 1A it shouldn't require a heatsink to be attached.










Of course, the whole purpose of a prototype is to "see" it in real life. As I looked over the layout I realized I should move a few things around. So, I have a new layout that will be used for the production boards (based on further testing of the prototype of course) that will relocate some of the solder pads, specifically the LED- and SWA/SWB. Basically I will flip their positions, which makes more sense that what I have now for a connection and current path perspective.

I'll need to characterize the current profile of the b3flex and then generate new b3flex specific current tables before doing more testing, especially at higher output current to verify the thermal path.

More updates to the thread as I perform more testing and have things to report.

cheers,
george.


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## mattthemuppet (Jul 16, 2004)

woo hoo hoo! Looking good. Always fascinating to see something like this develop too, thanks for bringing us along for the ride


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## manokaiser (Jun 30, 2008)

Great news! Keep it up George! XM-Lers are happy


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## Frede (Dec 7, 2009)

George, how would the new maxflex handle 3 xml's?


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## Rich_SC (Oct 10, 2009)

Frede said:


> George, how would the new maxflex handle 3 xml's?


Maxflex max current is 1300ma. XML's can handle up to 3A.


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## Frede (Dec 7, 2009)

Doh  I ment the new b3flex, not the maxflex


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## georges80 (Jan 5, 2010)

Frede said:


> Doh  I ment the new b3flex, not the maxflex


The b3flex will have various current tables, like all flex drivers.

I'm planning on supporting 6 current tables, 500mA, 1000mA, 1500ma, 2000mA, 2500mA and 3000mA.

So, if you want to drive your XML at 3000mA, choose the 3000mA current table. The design goal of the driver is to handle multiple series LEDs. 3 series XML's from 4 series li-ion cells (or similar voltage) would be no problem. The b3flex should be thought of as a scaled down (3A max output) version of the h6flex.

I just performed some characterization yesterday evening to determine the current versus control voltage profile so I can generate the current tables with their intermediate current levels. As expected the current versus control voltage is essentially half of the h6flex (since I'm using a sense resistor of 0.030 ohms versus the h6flex 0.015 ohms).

So, I will start testing the driver with b3flex specific current tables today. Once I've completed that testing I'll attach the driver to a heatsink via some thermal tape and start the temperature tests.

cheers,
george.


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## zemike (Sep 3, 2007)

Any possibility to include a pre-cut thermal pad for the b3flex? Or an aluminium shim?


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## georges80 (Jan 5, 2010)

I'll likely supply a small piece of the same adhesive thermal pad I ship with the h6flex etc. I've just run some tests this afternoon to load test the driver and check on the thermals. I won't supply an aluminium shim etc., since that means machine shops and whatever they decide to charge. I'll happily allow other folk to design/make/sell them, though I think anyone with a custom housing will just machine a pedestal for the b3flex to sit on.

At 1300mA output (L4 on the 3A range) I ran 1 XML from 14V nominal and then 3 series XML's. Both cases the driver was stable in 'air' with no additional heatsinking required. The driver was about 20C above ambient and ran 15 minutes without getting any warmer.

I then attached the driver to a heatsink via a small piece of thermal pad attached to the Red area outlined in my previous post showing the assembled prototype.

I ran 3024mA (measured) to the 3 series XML's for 15 minutes to achieve thermal steady state. The driver reached 20C above the heatsink temperature and would increase in temp 1C per heatsink increase of 1C. Measured output voltage was 10.00V (amusing) to the 3 series XML. This means 30.24W output power. I measure input voltage/current at the same time and calculated 94.88% efficiency which compares VERY closely with my h6cc measurements at 2.88A. This means that b3flex circuitry is dealing with 3A output correctly.

The thermal measurements with 30W output showed that the provided thermal path for the external heatsink was more than adequate to deal with the ~1.5W loss in the driver, so that's great news.

So, at this point all is looking very good for the design and other than tweaking some of the current tables to reflect new characterization data collected today, I'm very close to calling it done and ready to take to production.

I have some more tests to perform to verify efficiency at a few other points for documentation purposes. I'll take some pictures of the test setup running the 3 XML's at 3A for those that like visual stuff 

I've measured 'off' quiescent current at 70uA which unsurprisingly matches the h6flex typical values, so that part is working correctly as well. Since this is a baby version of the h6flex I wasn't expecting any nasty surprises, but it's always nice to have things work correctly.

cheers,
george.


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## georges80 (Jan 5, 2010)

So here's some pictures of the test setup. The b3flex proto is stuck down to the aluminium heatsink with some of the same Bergquist bondply 100 adhesive thermal pad material that I ship with some of my other drivers.

This test still has the initial 'rough' current tables, L1 will be closer to 50mA and L5 (on the 3A) will be closer to 3000mA, though both are pretty close already 

First picture shows the driver running at L1 with 3s2p P7's on my LED test jig.










Next we crank the output to L5 and the camera does its autoexposure thing...










Shot of voltage/current feeding into the b3flex prototype










After running for a while this is an IR scan of the b3flex with max temperature displayed on the bottom line:










And the heatsink temperature near where the driver is attached:










Next step is to clean up the pcb layout with any little tweaks I think would make the production boards closer to perfection and then start the process of generating gerber files and complete BOM for handoff to the assembly house to get things really moving forward.

cheers,
george.


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## georges80 (Jan 5, 2010)

The updated b3flex gerbers and BOM have been sent to the assembly house to start the process of getting production boards. My expectations are to have the first batch available around the end of February.

Current tables... I have 500mA/1000mA/1500mA/2000mA/2500mA and 3000mA tables in the firmware at present.

Do you folk thing that covers enough options for the LEDs of choice as well as undriven options for folk that need less light/extended runtimes etc?

This is the time to speak up about what you think is needed. I'll then decide if any additional tables should be added to the ones above. TIA for any input.

cheers,
george.


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## jbflyfshr (Jul 24, 2006)

an enclosure box option

 that way you could just soldier on connectors and you are all set...kind of kills the DIY part though 

SERIOUSLY, can't imagine you missed anything. That seems like the best of all worlds Driver to me, nube that I am.

JB


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## mattthemuppet (Jul 16, 2004)

that's the same table as the Lflex, right? That's worked fine for me in the past and any smaller jumps are unlikely to be particularly noticeable (or can be dealt with using the mode settings, L3, L4 etc).


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## yetibetty (Dec 24, 2007)

All sounds good to me George, not that I have ever heard of gerbers or BOMs before. I do think it would be nice to have a 750ma in there. Is it in a different current table?


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## georges80 (Jan 5, 2010)

Gerbers files are used by the PCB house to manufacture the bare boards. There is one file per layer of the PCB and that includes the copper layers, soldermask layers, silkscreen layers etc. There is also an NC file that specifies the coordinates and drill diameters for all the holes.

BOM = Bill of Materials, i.e. the parts list (full part numbers, reference designator etc etc) so that the assembly house knows exactly what parts need to be ordered and where they go on the PCB.

No 750mA table since I figure with modern LEDs there's no longer a need to support relics like the MC-E or Luxeons etc 

The tentative current tables ARE the same as for the lFlex. That's why I'm asking if any changes are needed, since no one has complained about the choice in the lFlex.

cheers,
george.


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## BrianMc (Jan 5, 2010)

500 mA table would drive XP-E Ambers at max current, Red and Red Orange XP-Es can do 700, 770 on flash, but that could be handled by running two in parallel from 1500 mA. So looks OK to me. Two old Luxeons, or MCEs could be handled in parallel on 1.5 A to get at max rated current or underdriven at 500 mA. FWIW: Looks OK to me.

BrianMc


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## emu26 (Jun 23, 2008)

Funny George, I thought BOM was the place we got our weather forecasts from 

As for the progress, in the words of Big Kev, "I'm excited"


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## mrradlos (Sep 3, 2010)

Is the new b3flex going to replace the h6flex? Some people might miss the higher current settings for SST50 or similar LEDs.

I'm using a h6flex with three XM-Ls as a mountainbike light for two years now. I ended up using it most of the time on L1 (50mA) as this gives enough light for slow uphills and "fireroads" while driving in a group. As people tend to use three and more LEDs in their lights, I think it would be nice to have a lower L1. I used the new simple KD 7135 3040mA-driver for a single XM-L helmet light and the low (7mA ??) is just fine to read a map or check your bicycle in the pitch dark - others find that a bit low for a single XM-L.


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## georges80 (Jan 5, 2010)

No, the h6flex won't be discontinued since it fills in where the b3flex leaves off.

Going lower than ~50mA is feasible since the ability is within the driver hardware of the b3flex to utilise PWM dimming to reach lower levels. The firmware currently performs all dimming including the 50mA L1 without the PWM control.

I'd consider providing a menu option to switch between L1 at 50mA and L1 at a much lower level. I'll see what is involved in the firmware and whether there are other folk that are interested in such a feature.

cheers,
george.


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## [jsl] (Sep 20, 2007)

I vote for lower L1 current as an option! The XML in my modified Petzl Micro is too bright at 50mA for reading, for example. Well, it's OK at 50mA, but the current could easily be much lower and it would still provide enough light for reading.

And while I'm at it, I think 750mA (or 800mA) table would still be useful, especially for headlight use. If it's possible to fit it into the firmware I don't see why it shouldn't be included.

In any case, I can already envision a couple of builds for which b3flex will be perfect! :thumbsup:


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## Ofroad'bent (Jul 10, 2010)

Can't you use Multi-mode on lowest setting within the lowest current table? That should be low enough for anyone, no?


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## georges80 (Jan 5, 2010)

Since in all current tables have the same L1 = 50mA, it would require providing a menu option to select a lower L1 for applications where the user desires a much lower output (reading light etc). i.e. L1 on the 500mA table is the same as L1 on the 3000mA table (presently 50mA).

I can see a lower L1 making sense for certain applications (reading, long runtime in case of being stuck/stranded etc) so I'll look into providing that capability. For my own lights I use to have a hidden menu for selecting what was called Super-Low... Anyhow, I'll look into where in the menu system it would make sense to have a selection option of a lower L1.

A 750mA table doesn't seem too useful at this stage, since the visible light difference between 1000mA and 500mA is really just an incremental step versus a factor of 2. i.e. if you want to conserve battery then choosing the 500mA table would double your runtime (on L5) while only reducing perceived brightness by maybe 20% over the 1000mA L5.

cheers,
george.


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## emu26 (Jun 23, 2008)

George, any idea when we can expect Cutter to have stock of these, I'm thinking of placing an order for some bits and pieces but will hold off if these are only a couple of weeks away?

Cheers


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## georges80 (Jan 5, 2010)

emu26 said:


> George, any idea when we can expect Cutter to have stock of these, I'm thinking of placing an order for some bits and pieces but will hold off if these are only a couple of weeks away?
> 
> Cheers


The assembly house started the run beginning of Feb and in "theory" I should receive blank boards to build up one test unit on a production PCB early next week. They will be getting the stencils made in parallel (for the solder paste process) and ordering parts.

So, I'm hoping I'd get production boards in hand by the end of Feb. Add a few days for programming/testing and then I'll be shipping boards to Cutter (they have a pending order waiting on me to deliver).

That means by the end of the first week of March they should have some stock on hand - IF all goes to plan 

cheers,
george.


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## georges80 (Jan 5, 2010)

Well, things got dragged out. I only yesterday received a panel of blank boards to assemble up a test unit to run through its paces prior to giving the assy house the go ahead. I finished assembling a board this morning and later today I'll see about loading firmware into it to test it. This means more like mid March before production boards are ready.

In the meantime, here's a couple of pictures (top/bottom) of the first assembled b3flex:



















The silkscreen polygon on the left side of the 2nd picture is the area to attach a heatsink path for the driver (to cool U1/Q2 of the 1st picture).

cheers,
george.


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## Goldigger (Nov 6, 2009)

This will hopefully be when my cutter order turns up.. some items on back order..
B3flex will be for a quad XT-E


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## kwarwick (Jun 12, 2004)

Me too :sad:

I'm building up a Spidereyes and decided to wait for the b3flex based on the better current table selection (2000, 2500, 3000mA) and smaller size vs. h6flex.

Very tidy looking board though... definitely looks like it will be worth the impatient wait!


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## georges80 (Jan 5, 2010)

Yeah, it's taken longer than I was expecting. Took about 2 weeks longer to get blank boards from the assy house so that pushed everything back.

Good news is I've built up a programming and test jig. I've loaded the firmware into the board and have connected a LED load and applied power and the board is running. STAT LED is doing its thing, SWA input is working, I can run the LED through UIP levels at the default 500mA drive and all is within spec.

Bunch more testing today/tomorrow to verify operating on the 3A table since that is the worst case for dissipation/electrical issues.

Will keep you all updated.

cheers,
george.


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## georges80 (Jan 5, 2010)

Everything seems to be working great. I've tested all current tables including 3A and all good to go.

I have added a 15th Menu to configure alternate L1 levels and that appears to be working great as well.

Nominal L1 is 50mA (all current tables) and menu 15 provides 5 alternate levels:

50mA constant current
37mA 75% PWM (400Hz)
25mA 50% PWM (400Hz)
12mA 25% PWM (400Hz)
5mA 10% PWM (400Hz).

Once you've selected your L1 current (50mA is the shipping default), then all operating modes that require L1 will use the new setting.

Presumably this will make the low power folk happy.

cheers,
george.


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## mattthemuppet (Jul 16, 2004)

nice addition there George. I love the constant improvements and updates that you add to the boards, even the little stuff.


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## rschultz101 (Oct 5, 2009)

Hi George, website is down,.... taskled.com
thought you might want to know ,...


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## georges80 (Jan 5, 2010)

rschultz101 said:


> Hi George, website is down,.... taskled.com
> thought you might want to know ,...


Yep, the server that hosts my website bit the big one last night and they are rebuilding/restoring the sites hosted on it. Hopefully it'll all be up again later today, but they stated it could take 48 hours - eek....

First big issue in a few years, so I can't complain about their service too much. My email is of course also down right now.

Thanks for the heads up though.

On the positive front, the assembly house was given the go ahead to assemble the boards on Monday, so they should be cranking through the process. Waiting to get an update (once my email is functioning again) on eta for boards in my hands.

As soon as taskled comes back online I'll be uploading preliminary manuals and tech specs of the b3flex driver, updated the docs on my laptop yesterday, just need to ftp them to my site.

cheers,
george.


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## Ofroad'bent (Jul 10, 2010)

*Thermal adhesive*



georges80 said:


> I'll likely supply a small piece of the same adhesive thermal pad I ship with the h6flex etc. I've just run some tests this afternoon to load test the driver and check on the thermals.
> 
> SNIP
> 
> cheers, george.


George (or others) a friend was asking me if the thermal tape you supply allows sufficient thermal transfer to attach an XM-L on a 16mm board to the housing?

I didn't know- I have used a different, thinner thermal tape in the past, or have used thermal grease if the housing presses the LED in place.


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## Goldigger (Nov 6, 2009)

Ofroad'bent said:


> George (or others) a friend was asking me if the thermal tape you supply allows sufficient thermal transfer to attach an XM-L on a 16mm board to the housing?
> 
> I didn't know- I have used a different, thinner thermal tape in the past, or have used thermal grease if the housing presses the LED in place.


I bought a sheet of this tape, just found out it doesnt bond to a painted surface very well..
I stuck a XML on a ali heat sink on the under side of the mill, behind the spindle.
Once it warmed up it starts to come away from the painted surface..stays on the ali no probs..


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## georges80 (Jan 5, 2010)

The adhesive that is used on the Bergquist material I supply is acrylic based. It is a very strong adhesive once allowed to cure/set for a few hours (24 hours for max strength). It needs a good deal of pressure (press hard) for a few seconds to make it stick. All this info is in the datasheet.

It obviously will not stick well to dirty/greasy/contaminated surfaces. It does work very well on clean bare metal or solder masked boards (like my drivers) or bare fiberglass.

Within the set-up time for the adhesive to set, it will not 'stick' very well, so it really does need to have the pressure applied and held. i.e. if you mount a LED and the wires pull on the LED then you won't get a good set to occur.

cheers,
george.


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## emu26 (Jun 23, 2008)

Ofroad'bent said:


> George (or others) a friend was asking me if the thermal tape you supply allows sufficient thermal transfer to attach an XM-L on a 16mm board to the housing?
> 
> I didn't know- I have used a different, thinner thermal tape in the past, or have used thermal grease if the housing presses the LED in place.


I've used the Cutter thermal tape for fixing boards to my light housings. So far no probs but I don't pull the lights apart to check that often.


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## georges80 (Jan 5, 2010)

Now that the taskled website it back up (hosting server crashed), I've updated it with the latest b3flex information. The product and technical b3flex literature is live on the website. The updated manual is also available in the b3flex technical section.

I've spent the last day running a bunch of tests and the results are the 3 efficiency graphs in the tech section - real measured efficiency, not "marketing" numbers 

cheers,
george.


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## Ofroad'bent (Jul 10, 2010)

georges80 said:


> The adhesive that is used on the Bergquist material I supply is acrylic based. It is a very strong adhesive once allowed to cure/set for a few hours (24 hours for max strength). It needs a good deal of pressure (press hard) for a few seconds to make it stick. All this info is in the datasheet.
> 
> It obviously will not stick well to dirty/greasy/contaminated surfaces. It does work very well on clean bare metal or solder masked boards (like my drivers) or bare fiberglass.
> 
> ...


George, I'm more concerned about thermal transfer properties. The adhesive will be well compressed in place by the lens cover and optic.

I've heard that Quazzle doesn't recommend tape for his units, but they run hotter than XM-L boards.


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## georges80 (Jan 5, 2010)

Ofroad'bent said:


> George, I'm more concerned about thermal transfer properties. The adhesive will be well compressed in place by the lens cover and optic.
> 
> I've heard that Quazzle doesn't recommend tape for his units, but they run hotter than XM-L boards.


I've had good success with thermal tape and it certainly "sticks" well with proper surface prep.

There are many thermal tape types on the market and of varying thickness. I went to the Strategies & Light show here in San Jose a month or so ago and it seemed there were dozens of companies (many new to me) with various thermal tape products.

The thermal performance for the same "product" will of course be better with the thinner materials. So, just choosing a thinner product will improve the performance. Assuming nice flat surfaces that don't require gap filling, a very thin material will work well.

The thermal tape products continue to be improved as more companies get into that growing market and compete for the top of the pile.

Many of the thermal tape advantages are for manufacturing purposes - i.e. ease of assembly etc etc.

I still feel that where the ultimate thermal transfer is needed for a particular product, that it would be hard to beat a VERY thin layer of thermal paste/epoxy that has been CORRECTLY applied (see below).

During my thermal tests with the maxflex5/6 driver, I found that applying arctic alumina epoxy CORRECTLY is critical for thermal transfer. Starting with 2 CLEAN and FLAT surfaces you need to apply the paste to one surface with a spatula (preferably as wide as the area that is being treated) and then you want to drag the paste so it is uniformly applied, no gaps, no high spots, no low spots. Preferably you want to do the same to the mating surface. Then when you bring down the driver/led you need to move it around to properly seat it and spread the paste for even coverage.

Ensuring the even coverage of the thermal paste/epoxy AND keeping it as THIN as possible is where you can a) lose a lot of thermal transfer performance and b) why thermal tape is much preferred since it ensures even coverage, even attachment and consistent thickness etc etc.

So, from the above, you can see that industry would prefer the tape since it is easier to use in a mass production environment with much more consistent results. Over engineering the thermal path (area of contact) and type of tape in use, would provide designed-in margins to ensure good/reliable/consistent performance across a mass assembled product line.

The correctly applied thermal grease/epoxy/paste may provide better performance, but applying it properly for consistent results would be difficult in a fast moving assembly line.

Finally, my preference, is to use thermal tape where possible. I use a thermocouple and IR gun to measure driver temperature in worst case combinations on LED/Current/Input voltage for each driver that needs a thermal path. I then decide if thermal tape is sufficient to deal with a particular driver's worst case results.

For ALL my drivers EXCEPT maxFlex I recommend thermal tape since it is adequate and ensures good performance and ease of assembly for my customer. maxflex on the other hand can be pushed very hard by some of you more adventurous types and it needs the best possible heat path once power dissipation levels reach >1.5W, especially given the small size of the board and the small available area for mounting to a heatsink.

cheers,
george.


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## brad72 (Jun 12, 2009)

Excellent write up George. I agree that the thermal tape is much easier but do also prefer epoxy on the maxflex. I also had a copper heat pipe on the top IC of the maxflex to get rid of more heat form the driver.


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## georges80 (Jan 5, 2010)

This morning my assembly house updated me with new status. I should be receiving production b3flex drivers later this week... Yippee 

cheers,
george.


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## Goldigger (Nov 6, 2009)

Hi George,
Just noticed on your website the description says boost driver..its also a buck driver further down.
If this can do both that would be amazing..

b3Flex Boost Driver

Perfect solution for driving series strings of power LEDs such as:

- XM-L - P7 - MC-E (parallel die)


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## georges80 (Jan 5, 2010)

Fixed the typo, thanks. I'm sure there's more typos hiding in the b3flex & tech descriptions since I was updating a LOT of sections of the website.

So, if anyone finds errors, feel free to bring them to my attention.

cheers,
george.


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## georges80 (Jan 5, 2010)

Latest update from my assy house is that I should get boards this week. There was an error in the solder paste stencils they had had made and that prevented the boards being run Friday. They are aiming to ship to me Tues/Weds. We'll see... won't be the first time that schedules have slipped a few days or more.

The trials and tribulations of a completely new design/PCB layout/Bill of Materials. They have to program new pick & place instructions for the components, do new stencils for the solder paste and order/inventory a new range of parts. Lots of new steps for Murphy to interject....

Anyhow, fingers crossed 

cheers,
george.


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## kwarwick (Jun 12, 2004)

Just remember, Murphy was an optimist. *waiting*


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## brad72 (Jun 12, 2009)

Yep good old Murphy......a $1000 electrical part will always fail 1st, protecting the 50c fuse.


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## georges80 (Jan 5, 2010)

Well, Murphy popped in to mess things up....

Latest update from the assembly house this morning is that one of the parts that Digikey shipped was the wrong footprint. The correct part was ordered, the wrong part was shipped. So, today the assembly house hopefully scrambled to get Digikey to ship the right part overnight. The boards are mostly assembled with at least one side complete. So, I'm assuming Monday or Tuesday before I receive them. They have 300 boards waiting on the correct IC.

Oh well, at least they're on the machines ready to finish up. The correct part is in stock, so it's just a matter of waiting a few more days (at least that's what I tell myself to feel better)....

cheers,
george.


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## kwarwick (Jun 12, 2004)

Hopefully with no further updates this doesn't mean Murphy has been busy again, but rather that George is very busy testing and loading firmware to begin fulfilling the massive pent up demand.


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## georges80 (Jan 5, 2010)

Part was reordered from the distributor (that messed up) and it arrived yesterday morning. Boards were in final assembly yesterday and I was hoping they would be shipped late yesterday, but apparently not. So, hopefully they shipped today (still waiting for an update).

Anyhow, I "should" receive them this week...

cheers,
george.


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## Rekkie (May 26, 2011)

Hi George

I know this is prob too late, but any chance of the addition of the configurable strobe menu like with the new H6flex UNI3 firmware? 

Keep up the good work!!


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## georges80 (Jan 5, 2010)

Rekkie said:


> Hi George
> 
> I know this is prob too late, but any chance of the addition of the configurable strobe menu like with the new H6flex UNI3 firmware?
> 
> Keep up the good work!!


Yes, of course **ALL** Flex drivers now have the UI-UNI3 firmware.... All the Flex drivers share the same source code (with conditional switches for specific hardware differences), so whatever one driver gets, all the others get it to...

AND.... Murphy is still hard at work, bastard! Tracking shows Express Mail was shipped from the assembly house and departed from the east coast of the US to me yesterday, with guaranteed delivery by 12pm local time. It is now 4pm local time here and nothing has shown up yet and tracking doesn't even show it having arrived on the west coast.... So, unless they deliver in the next hour or so, it looks like tomorrow or even worse news which I don't want to consider at this point ........

cheers,
george.


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## kwarwick (Jun 12, 2004)

Grrrrr that Murphy! The sad thing is even after you ship them I'm still looking at typically 10 business days for USPS and Canada Post to deliver them to me. 

serenity now... serenity now...


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## Rekkie (May 26, 2011)

georges80 said:


> Yes, of course **ALL** Flex drivers now have the UI-UNI3 firmware.... All the Flex drivers share the same source code (with conditional switches for specific hardware differences), so whatever one driver gets, all the others get it to...


Awesome!! Had a look at the PDF from the Taskled site of the b3flex and it still shows UNI2-firmware, hence asking.

Can't wait for them to be available!!! Murphy should get kicked in the plums


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## mrradlos (Sep 3, 2010)

kwarwick said:


> serenity now... serenity now...


serenity .... serenity...... serenity.............

had to look that up in the dictionary .... have to learn that

serenity ..... serenity


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## georges80 (Jan 5, 2010)

Ok, have to head out, but the Postman just delivered the Express package.

B3flex have arrived, I programmed/tested 2 and all is good. Lots to program and then test. I'll have to see how many were shipped (suppose to be 200). Most of these are spoken for, but I'll be emailing folk on my contact list (in order) if there are more left over. Another 300 should be arriving next week.

I'll be updating the b3flex online documentation/manual later today/tonight.

cheers,
george.


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## deesta (Sep 7, 2008)

georges80 said:


> Ok, have to head out, but the Postman just delivered the Express package.
> 
> B3flex have arrived, I programmed/tested 2 and all is good. Lots to program and then test. I'll have to see how many were shipped (suppose to be 200). Most of these are spoken for, but I'll be emailing folk on my contact list (in order) if there are more left over. Another 300 should be arriving next week
> 
> ...


:thumbsup:

Woo hoo!


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## kwarwick (Jun 12, 2004)

georges80 said:


> Ok, have to head out, but the Postman just delivered the Express package.
> 
> B3flex have arrived, I programmed/tested 2 and all is good. Lots to program and then test. I'll have to see how many were shipped (suppose to be 200). Most of these are spoken for, but I'll be emailing folk on my contact list (in order) if there are more left over. Another 300 should be arriving next week.
> 
> ...


That's good news, George! Hopefully at this point Murphy has gotten bored and moved on to introduce some one new to his always enjoyable law.


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## emu26 (Jun 23, 2008)

kwarwick said:


> That's good news, George! Hopefully at this point Murphy has gotten bored and moved on to introduce some one new to his always enjoyable law.


Be careful what you wish for, it might be the postie that does your run waiting for an introduction


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## georges80 (Jan 5, 2010)

I've programmed up a bunch of panels and tested one so far and all is good to go. Assembly house actually shipped 300 units, so I have plenty to go around beyond the initial wait list. More will be delivered within a week.

Boards look great, assembly house did an excellent job (US based). I've updated the manual and website to reflect the latest info on the b3flex so at this point all is good to go.

Edit: One other thing. I just remembered that I've added a 0.1uF capacitor across the SWA/SWB input connections, so that should help make the b3flex more tolerant to longer leads used for remote switches.

cheers,
george.


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## jbflyfshr (Jul 24, 2006)

That would make it perfect to sub for my H6Flex...I wonder where I could get my hands on one??


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## kwarwick (Jun 12, 2004)

jbflyfshr said:


> That would make it perfect to sub for my H6Flex...I wonder where I could get my hands on one??


taskled.com


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## emu26 (Jun 23, 2008)

Mr warwick, have you got yours yet or has the postie been hit by Murphy?


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## kwarwick (Jun 12, 2004)

emu26 said:


> Mr warwick, have you got yours yet or has the postie been hit by Murphy?


Mine were shipped on Monday, so I hope to receive them sometime next week.


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## Goldigger (Nov 6, 2009)

I'm just milling another one of my tripple cute housings.. (3 x XM-L ledil cute ss lens)
I've got some h6flex's here and also some b3flex on their way to me..
Is there any advantage to using a b3flex over a h6flex? 

With the b3flex, as its double sided can I still stick the IC side down to the rear of the leds..like I would with a h6flex?


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## kwarwick (Jun 12, 2004)

Goldigger said:


> I'm just milling another one of my tripple cute housings.. (3 x XM-L ledil cute ss lens)
> I've got some h6flex's here and also some b3flex on their way to me..
> Is there any advantage to using a b3flex over a h6flex?
> 
> With the b3flex, as its double sided can I still stick the IC side down to the rear of the leds..like I would with a h6flex?


I guess the big advantage of the b3flex is the smaller diameter... 1" vs. 1.3". You'll need to make a little pedestal to attach the bottom of the b3flex though.

If your application is driving XMLs with 3A max the b3flex gives you a few more current tables below that max.

And of course the new UNI-3 code is nice with the programmable strobes.


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## Goldigger (Nov 6, 2009)

I personally don't use the strobes..riding round the woods at night with a strobe going is like blinking like a maniac with a light on constant 
I just wondered if maybe one was a bit more efficient than the other..probably not..


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## kwarwick (Jun 12, 2004)

Goldigger said:


> I personally don't use the strobes..riding round the woods at night with a strobe going is like blinking like a maniac with a light on constant
> I just wondered if maybe one was a bit more efficient than the other..probably not..


Yeah, I never use strobe on a front light... but if I ever get around to making that 3 xpe red tail light it would be a good driver for that.

I'd say if you've got the space might as well use the h6flex you already have as is easier to mount with the flat back and the supplied thermal tape.


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## georges80 (Jan 5, 2010)

H6flex and b3flex are the SAME driver design. The only differences are some of the components (inductor etc) are sized down on the b3flex for 3A maximum and to make the board smaller. Efficiency will be very similar since they share the same design/architecture etc.

So, if all you need is 3A max, then choice comes down to size and cost.

Since folk always want smaller, the only way that can happen is components on both sides, so yes, b3flex is only 1" in diameter versus 1.3" but now you need to deal with components on both sides.

Running b3flex at 3A requires attaching to a heatsink. That can be as simple as a small cut rod (cylinder) of aluminium/copper faced flat on opposite ends and then thermally attached (epoxy/adhesive thermal pad) to the polygon area of the b3flex and then to the housing, or as fancy as a CNC machined pedestal in the housing. Basically it has a similar mounting requirement as the maxflex and also the old b2flex.

If running the b3flex at say 1.5A with 3 XPG and 4 li-ion, then the driver runs efficiently enough that it doesn't require a heastsink attachment, unlike the older b2flex that did.

So, if you have the room and already have the h6flex and don't need fancy new strobe modes, then you may as well use what you have since it really is just the big brother of the b3flex.

cheers,
george.


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## Goldigger (Nov 6, 2009)

Thanks for the explanation George..
I'll keep the B3flex for some smaller builds..


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## kwarwick (Jun 12, 2004)

Murphy gave me a break and my B3flex arrived in the mail yesterday and is now installed in my Troutie Spidereyes. Glad I waited for this driver as it would have been challenging to fit a H6flex in the tight driver compartment of this host. 

Preliminary testing was all good and I will take her out for a shakedown run this evening.


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## ThinkBike (Jun 16, 2010)

Would it be possible to put the driver in a separate housing? Has anyone ever tried this?

Battery----------Driver-----------LED Housing 

What would be the advantages? 

What would be the disadvantages?


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## emu26 (Jun 23, 2008)

I think you loose the temp monitoring of the leds if you remote house the driver, assuming the b3flex has it to start with


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## Vancbiker (May 25, 2005)

ThinkBike said:


> Would it be possible to put the driver in a separate housing? Has anyone ever tried this?
> 
> Battery----------Driver-----------LED Housing
> 
> ...


It has been done by a few DIYers. It lets you build a smaller lighthead but that may not really be good for heat dissipation. You also lose the temp sensing of the LED housing with the flex family of drivers.

Both my current microlight designs have the driver in the battery. The "mk3" version (on the drawing board in my head) will have an lflex in the lighthead. I feel better knowing that the light will dim down if the user leaves it on high while stopped or moving slowly on a warm night.


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## brad72 (Jun 12, 2009)

I agree with Vancbiker. If you are not running the leds to there full capacity or your have a housing that can thermally handle the leds on full then a remote driver is fine. If you have any risk of cooking the leds because of poor thermal performance then the driver mounted on the light housing is best.


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## troutie-mtb (Sep 20, 2007)

kwarwick said:


> Murphy gave me a break and my B3flex arrived in the mail yesterday and is now installed in my Troutie Spidereyes. Glad I waited for this driver as it would have been challenging to fit a H6flex in the tight driver compartment of this host.
> 
> Preliminary testing was all good and I will take her out for a shakedown run this evening.


Nice and neat sat in there Karl certainly more room than with a H6flex .
be interested to hear your thoughts when you have tried it out 
looking at your wiring I am assuming there is no resistor needed for the stat led in the switch 
( not yet read the manual )


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## kwarwick (Jun 12, 2004)

troutie-mtb said:


> Nice and neat sat in there Karl certainly more room than with a H6flex .
> be interested to hear your thoughts when you have tried it out
> looking at your wiring I am assuming there is no resistor needed for the stat led in the switch
> ( not yet read the manual )


The b3Flex provides 3V via a built-in 100 ohm resistor to the status LED which is convenient.

I'll give you my thoughts on the Spidereyes probably later today... short story, I love it!

Karl


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## mattthemuppet (Jul 16, 2004)

how's the switch kept in, epoxy? V. neat wiring job and great to see the b3flex out in the wild.


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## kwarwick (Jun 12, 2004)

The housing is threaded and there is a gasket between the switch body and the housing so it tightens down very snug. 

Internal wiring is all done with 24awg Teflon insulated wire which keeps the wire size down while being extremely heat resistant. I find it much nicer to work with as the insulation doesn't melt back from the heat of soldering. Downside of this type of insulation is it is harder to cut (I use an exacto knife) and not very flexible so you have to be careful not to move the wire back and forth a lot as this will tend to break the wires near the solder joints.


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## mattthemuppet (Jul 16, 2004)

ah, that's a neat solution. Saves dealing with those fiddly nuts, which has to be a plus.


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## zemike (Sep 3, 2007)

kwarwick said:


> Murphy gave me a break and my B3flex arrived in the mail yesterday and is now installed in my Troutie Spidereyes.


Nice build. How did you deal with the thermal pad?


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## kwarwick (Jun 12, 2004)

zemike said:


> Nice build. How did you deal with the thermal pad?


I fashioned a shim from a thin piece of aluminum (in keeping with the mtb theme I cut it out from an old chain ring) and bonded it between the driver and housing with Arctic Alumina thermal adhesive.


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## zemike (Sep 3, 2007)

kwarwick said:


> I fashioned a shim from a thin piece aluminum


I have suggested this to George - to offer in option a thin shim. It can be made cheaply in moderate quantities by laser cutting.


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## kwarwick (Jun 12, 2004)

zemike said:


> I have suggested this to George - to offer in option a thin shim. It can be made cheaply in moderate quantities by laser cutting.


I certainly would have appreciated that... took me well over an hour of cutting and filing with crude tools to get fashion it to the correct shape and size.


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## georges80 (Jan 5, 2010)

Well, I just received a quote to run 500 pieces of 0.09" thick and 0.32" diameter aluminium "shims". Not particular cheap and realistically I'd need to sell them at $1 each which seems insane to me for a small piece of Al.

I picked the size so it would work for the maxflex6 as well.

What do you folk think?

I'll be getting quotes from a few other places over the next few days.

cheers,
george.


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## troutie-mtb (Sep 20, 2007)

Have a look for aluminium washers I got some 2 mm thick from evilbay a while ago and not expensive .

surely every diy light builder has a dead led on a star so could reuse the star for a shim material .only need a bit of cutting and sanding 

Re the Spidereyes that Karl has the first batch was going to have a pillar for the B3flex but due to Georges Gremlins in the supply chain I had to go with the H6flexs and a very snug fit.

my next batch will have the b3flex mount built in


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## kwarwick (Jun 12, 2004)

georges80 said:


> Well, I just received a quote to run 500 pieces of 0.09" thick and 0.32" diameter aluminium "shims". Not particular cheap and realistically I'd need to sell them at $1 each which seems insane to me for a small piece of Al.
> 
> I picked the size so it would work for the maxflex6 as well.
> 
> ...


$1 does seem like a lot from a pure materials point of view, but I'd gladly pay that to avoid all the cutting and sanding needed to make my own.


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## ThinkBike (Jun 16, 2010)

To me, $1.00 seems insanely cheap.

I get a laser cut, perfectly sized shim and it comes directly from the manufacturer of the driver. I don't have to source it from somewhere else, and it will come in the same shipment, along with my driver? It's a no brainer for $1.00. At least for me.


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## zemike (Sep 3, 2007)

georges80 said:


> Well, I just received a quote to run 500 pieces of 0.09" thick and 0.32" diameter aluminium "shims".


The idea regarding Al stars was a good one. Maybe you should ask your PCB manufacturer if they can make the shims from leftover Al substrate.


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## Toaster79 (Apr 5, 2010)

b3flex and maxflex shims:


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## wquiles (Aug 22, 2010)

ThinkBike said:


> To me, $1.00 seems insanely cheap.
> 
> I get a laser cut, perfectly sized shim and it comes directly from the manufacturer of the driver. I don't have to source it from somewhere else, and it will come in the same shipment, along with my driver? It's a no brainer for $1.00. At least for me.


That is how I would like it as well. Simple and to the point - you know it "will work", with no second guessing :thumbsup:

Will


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