# 1st LED light, lots of questions



## mattthemuppet (Jul 16, 2004)

right, where do I start?! I've been lurking on these forums for a while after my 1st night ride in a couple of years - my 7yr old DIY halogen has gone from being half decent to being utter pants in comparison to what's around now. Plus, as a helmet light it's heavy (150-170g I seem to remember) and too high up which seriously messes around with my helmet.

So, I'm planning a 2up helmet light, Achesalot style with 1in square aluminium tubing, mimicking Scar's Amoeba light (imitation is the sincerest form of flattery and all that ). I have a rough design and a bunch of info swirling round my head, but now I need to start nailing down the details.

Aim - light (100g or less) helmet light with decent throw AND some spill. It will be my only light. Needs to be dim-able/ switchable for climbing and endurance races. Will be designed to work with my existing 11x NiMH AA packs (13.2V, supposedly 3000mAh). Needs to be sealed as much as possible, it's not blazingly green in central PA without reason.

Housing - seems straight forward, copy the pros  Will use Lexan or equivalent as a lens cover if using reflectors. I have a bunch of old northbridge and UPS heatsinks to stick on as necessary.

LEDs - now here's the issue. I was initially planning an XP-G/ MC-E hybrid light a la Achesalot (XP-G and MC-E in series with 2s2p for the 4 MC-E dies) using 1A driver to give ~500mA per LED. However, the lack of decent (as far as I'm aware) 20mm optics for the MC-E, plus the beamshot pics of Scar's 2xXP-G light are making me reconsider. Would 2x XP-G in parallel (so max 1A per LED) be a better, simpler and cheaper choice?

Optics - Reginas seem to be the bees knees for XP-G. What are the best options for spot and for flood? If I'm going the hybrid route, the XP-G will have a spot. What about MC-E, has anything improved on that front? I'd really rather not have to step up to a larger optic.

Driver - I was originally set on a simple 3023 dim-able BuckPuck, but the b2flex looks pretty cool. It's ~$10 more, but I'm not interested in chopping and changing stuff once it works so $10 over 2-3yrs (or 7, going by the last one) is chump change. By only issue with the b2flex is the abundance of modes - I really only want low-high-turbo. Also, what current can I safely drive XP-Gs and MC-Es up to? I know they're rated 1000mA and 700mA, respectively, but the b2flex goes up to 1.5A (IIRC) - would this be too much?

Switch - I'm open to good suggestions for either dimmer pots or push to make switches (and waterproof domes). There are a lot of different ones in use on here and I have had time to check them all out (sorry, being lazy)

Cable and connectors - I'll have a sealed wire coming out of the back of the housing to a connector at the back of my helmet. I've been using simple 2 strand appliance cord and latching RC style connector (you know, the ones with a D and O shaped holes with a little latch). Any suggestions on doing a better job would be welcome!

I'll most likely be getting most of this from Ledsupply, taskLED and DX (though postage times and QC seem somewhat variable from there). Optics/ reflectors I'm not sure - perhaps off a CPF groupbuy, though I'd prefer to buy in the US for simplicities sake.

Any thoughts and suggestions would be very welcome, then I will no longer have to hang my head in lumen shame!


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## Bobblehat (Dec 1, 2007)

Welcome mat :thumbsup:

Seems you are thinking along the right lines ..... so have you looked at .....

http://forums.mtbr.com/showthread.php?t=654464

and this

http://www.singletrackworld.com/forum/topic/diy-700-lumen-batteries-inside-light

.... to see how they developed once the batteries came outside the case?

Also there is some similarity to what you want except I'm going for bar lights here ....

http://forums.mtbr.com/showthread.php?t=657480

The battery pack you have sounds reasonably suitable for those builds and the teapot driver used allows a few levels of brightness if you use an on/off/on toggle switch (just one example).

Other ideas can be found in Citizen Kane's Easy DIY thread .... do a search in this forum.


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## mattthemuppet (Jul 16, 2004)

thanks Bobblehat!

I'd seen the Hammond light-in-a-box, but completely forgot it that it had XPGs and Reginas. I'll have to go back and check out Ledil's site for reflector specs (is there more than 1 type of Regina?).

I'm liking the Teapot driver, good price too and no more frills than I need (I'm always getting my light levels mixed up with the Lightbrain in my halogen).

I'll go back and check out the Citizen Kane's thread - most of the information I've stuffed in my head from this forum has since fallen out again..


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## Vancbiker (May 25, 2005)

I'll throw in my $.02. Go with the bFlex driver. The ability to monitor your battery and dim the light if it overheats is very useful.


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## brad72 (Jun 12, 2009)

Regarding the drivers, the bflex is programmable so you can set the low, med & high current levels to what ever you want ( I run 350, 700, 1000mA), plus many other parameters like low voltage warning and cutoff, heat sensing etc. Another advantage over the buckpuck is you don't need an inline switch from the battery. The bflex uses the momentary switch, 1 click switches the light on, further clicks cycle through the power levels, the a long press turns the light off. Neat and easy. No need for pots, nice and small, just works well. I used buckpucks in my 1st few builds but now only use bflex or maxflex's.

Please tell me if I'm wrong but wouldn't 2 xpg's in parallel driven at 1A only give 500mA to each led?


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## Bobblehat (Dec 1, 2007)

brad72 said:


> ........... Please tell me if I'm wrong but wouldn't 2 xpg's in parallel driven at 1A only give 500mA to each led?


Yep! With an 11 AA NiMH pack, you might as well put the xp-g's in series with either teapot or bFlex drivers.

Teapots (or equivalents) vs bFlex (or equivalents) ..... guess it all depends on budget and functionality needed ...they are both highly recommended and reliable drivers.

edit: just one type of regina ...but many types of Ledil lenses and reflectors ....... see here for a company with a good range of optics/reflectors .... other suppliers and optic companies are available!


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## buddhak (Jan 26, 2006)

Why not drive 3 XPGs in series with a buck driver and a 13.2V battery? I don't know whether or not the Hammond box design has that kind of flexibility, but the Achesalot certainly does.


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## mattthemuppet (Jul 16, 2004)

you're right everybody, the 2 XP-Gs would be in series. That would give 500mA per LED from a 1000mA driver, right? As you may have guessed, maths isn't my strong point so don't be afraid to patronise me 

thanks Vancbiker and Brad on the b2flex advice. At the moment, it's more an issue of complexity - more features can be both a good thing and a bad thing at times. I'll have to have a think and get in contact with the guy that makes the b2flex. Any recommendations on a waterproof/able momentary switch that would work with the b2flex?

buddhak - the main reason over 2 LEDs vs. 3 is weight/ thermal management/ runtime vs. having enough light. On the helmet 2 LEDs should be more than enough (I've been coping with 30ish W of halogen, so this'll definitely be an improvement), while remaining lighter and lower profile than the light I have at the mo'. Nearly yanked my head off last night with my current light. I'm not averse to having 3x XP-G, I'd just rather see if 2 LEDs is enough 1st.

Any views on 2x XP-G vs. 1x XP-G (spot, with Regina) + 1x MC-E (flood, Ledil square optic or Boom SS?). If I go 2x XP-G, would it work with both spot (Regina) or would it be worth mixing spot (Regina) and flood (?).

My battery died 1/2 through last nights ride (the peril of charging AAs individually) and I borrowed another rider's spare Niterider Trinewt (a 3up of some sort) - wow! Even on the bars it was awesome, so I absolutely have to get moving on this ASAP  All the help is much appreciated! Hopefully, the shipping time on the parts will give me time to service my forks, build a set of shelves for the wife and change the cambelt on my car


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## Homebrew (Jan 2, 2004)

mattthemuppet said:


> you're right everybody, the 2 XP-Gs would be in series. That would give 500mA per LED from a 1000mA driver, right? As you may have guessed, maths isn't my strong point so don't be afraid to patronise me
> 
> Any views on 2x XP-G vs. 1x XP-G (spot, with Regina) + 1x MC-E (flood, Ledil square optic or Boom SS?). If I go 2x XP-G, would it work with both spot (Regina) or would it be worth mixing spot (Regina) and flood (?).


Kirchhoff says in series both LEDs get the same current but you need twice the drive voltage.

I would just do the 2 x XP-G with Regina and forget the MC-E. XP-G are naturally floody enough and Regina gives good spill. Even at 750mA (half of maximum drive current) it's still 550+ lumens of well placed light.


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## Bobblehat (Dec 1, 2007)

If you have 2 in series, both have 1000mA going through them, and as HB says you need a higher battery voltage to do that ....which you have more than enough in 11 * AA's for 2 or 3 LEDs in series.

Aren't these drivers more efficient as the total Vf of the LEDs gets nearer the battery voltage (allowing for the driver overhead needed)? So 3 in series makes best use of the 11 * AA pack the OP intends to use? Also the LEDs are slightly more efficient at converting watts to lumens at lower currents, so 3 LEDs run at a lower current producing the same amount of lumens as 2 LEDs at a higher current gives a longer run time. 

But as you say, it's all a balance of weight and run-time .... and cost even!


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## mattthemuppet (Jul 16, 2004)

Homebrew said:


> Kirchhoff says in series both LEDs get the same current but you need twice the drive voltage.


who's Kirchhoff? Oh right, kinda important guy  Thanks for that Homebrew, penny has finally dropped!

Can XP-Gs be safely driven above 1000mA (IIRC, the new b2flex can run up to 1500mA), given enough heatsinking and thermal management? Or best to keep things reasonable?



Homebrew said:


> I would just do the 2 x XP-G with Regina and forget the MC-E. XP-G are naturally floody enough and Regina gives good spill. Even at 750mA (half of maximum drive current) it's still 550+ lumens of well placed light.


doh, I see you've already answered my question above  Sounds like 2x XP-G with Reginas are the way to go, especially for a helmet light. Saves me some cash (MC-Es aren't cheap) and hassle with optics too.


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## mattthemuppet (Jul 16, 2004)

Bobblehat said:


> If you have 2 in series, both have 1000mA going through them, and as HB says you need a higher battery voltage to do that ....which you have more than enough in 11 * AA's for 2 or 3 LEDs in series.
> 
> Aren't these drivers more efficient as the total Vf of the LEDs gets nearer the battery voltage (allowing for the driver overhead needed)? So 3 in series makes best use of the 11 * AA pack the OP intends to use? Also the LEDs are slightly more efficient at converting watts to lumens at lower currents, so 3 LEDs run at a lower current producing the same amount of lumens as 2 LEDs at a higher current gives a longer run time.
> 
> But as you say, it's all a balance of weight and run-time .... and cost even!


I'm thinking I may get the 3rd LED and reflector when I place my order. I've have an excess of alloy square tubing and I'm planning on assembling the housing with bolts and silicon so I can disassemble things if I need to. That way, if 2x LEDs aren't enough or are so lightweight I have room to spare, I can always make a 3x LED housing and strip the parts out of the original.

I think that would be the only way I will be able to find out the right balance between weight/runtime/light output (cost isn't so much of an issue, it should only be an extra $10-15).


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## Vancbiker (May 25, 2005)

mattthemuppet said:


> Can XP-Gs be safely driven above 1000mA (IIRC, the new b2flex can run up to 1500mA), given enough heatsinking and thermal management? Or best to keep things reasonable?
> 
> doh, I see you've already answered my question above  Sounds like 2x XP-G with Reginas are the way to go, especially for a helmet light. Saves me some cash (MC-Es aren't cheap) and hassle with optics too.


XP-Gs can be run at 1500mA. You will need good heat management! Minimum 2 sq inches surface area per watt would be my advice.

Skip the MC-Es unless you can use a Fraen 35mm reflector or Ledil Iris optic (38mm) in your housing.


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## mattthemuppet (Jul 16, 2004)

Vancbiker said:


> XP-Gs can be run at 1500mA. You will need good heat management! Minimum 2 sq inches surface area per watt would be my advice.
> 
> Skip the MC-Es unless you can use a Fraen 35mm reflector or Ledil Iris optic (38mm) in your housing.


cool, thanks! I'm pricing up XP-Gs and Regina reflectors now. I'm also 99% sold on a b2flex, just have to get in touch with the maker to ask a few questions (mostly what combinations of power I can have - be nice to have 350mA, 750mA and 1200-1500mA).

How many whats would 2x XP-G at 1500mA consume? I'm guessing ~9W at 1000mA (7W for the LEDs + 2W for the driver), so ~14W at 1500mA? Off the top of my head the housing should provide ~14sq.in. area bare, so I'd need to double that at least with heatsinks. I'll have to go measure the ones I have and see what I can do. On the plus side, night riding season is reasonably cool/ cold here 

off to research connectors and switches..


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## slcpunk (Feb 4, 2004)

mattthemuppet said:


> cool, thanks! I'm pricing up XP-Gs and Regina reflectors now. I'm also 99% sold on a b2flex, just have to get in touch with the maker to ask a few questions (mostly what combinations of power I can have - be nice to have 350mA, 750mA and 1200-1500mA).
> 
> How many whats would 2x XP-G at 1500mA consume? I'm guessing ~9W at 1000mA (7W for the LEDs + 2W for the driver), so ~14W at 1500mA? Off the top of my head the housing should provide ~14sq.in. area bare, so I'd need to double that at least with heatsinks. I'll have to go measure the ones I have and see what I can do. On the plus side, night riding season is reasonably cool/ cold here
> 
> off to research connectors and switches..


not sure if this will be of any help, found this switch mentioned in another thread about bflex's ... http://www.radioshack.com/product/index.jsp?productId=2062508

That switch is lame ... digikey seems to have better ones... here's a link to their catalog ... they show switches and boots:

http://onlinecatalog.digikey.com/We...PageLabel=2218&cshift_ck=null&client_id=5042#

( not 100% exactly what is needed .. the bflex docs say:
The switch needs to be a momentary action, push to close type, i.e. normally open contacts. )

also, curious where you will source the reginas and xp-gs ... i can't find one place with good pricing/shipping for US delivery. ( digikey for regina, ledsupply for xp-gs ... i wasn't sure, but i don't think digikey has the nice R5 xp-g in single units on a star ... ) if you find both at the same place, please share?

i've been following your thread ( stalking even ) as I'm in the same boat. Also originally thought buckpuck, but after reading about the different drivers, the bflex sure does seem good. ( actually less complex, because its all built in ) only downside i could see is size. also couldn't be sure about efficiency ... so many variables there.

keep it coming..can't wait to see it take shape

I keep editing this ... remember the bflex comes with a switch too .. vancbiker used it I think as well as others. just have to cover to make water proof.


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## MtbMacgyver (Jan 23, 2007)

mattthemuppet said:


> How many whats would 2x XP-G at 1500mA consume? I'm guessing ~9W at 1000mA (7W for the LEDs + 2W for the driver), so ~14W at 1500mA? Off the top of my head the housing should provide ~14sq.in. area bare, so I'd need to double that at least with heatsinks. I'll have to go measure the ones I have and see what I can do. On the plus side, night riding season is reasonably cool/ cold here


Your numbers are a little high. Using the Vf from the datasheet, 2 XPGs at 1 amp will consume 6.6 watts. The blex efficiency is typically 90% or better, so taking that into account total power consumption would be around 7.3 watts. In actual practice, the real world Vf is usually lower than the datasheet, so power consumption will actually tend to be a little bit lower.

At 1.5 amp, the leds will consume 10.5 watts, and total power include driver loss will be around 11.7 watts.


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## Homebrew (Jan 2, 2004)

mattthemuppet said:


> cool, thanks! I'm pricing up XP-Gs and Regina reflectors now. I'm also 99% sold on a b2flex, just have to get in touch with the maker to ask a few questions (mostly what combinations of power I can have - be nice to have 350mA, 750mA and 1200-1500mA).
> 
> How many whats would 2x XP-G at 1500mA consume? I'm guessing ~9W at 1000mA (7W for the LEDs + 2W for the driver), so ~14W at 1500mA? Off the top of my head the housing should provide ~14sq.in. area bare, so I'd need to double that at least with heatsinks. I'll have to go measure the ones I have and see what I can do. On the plus side, night riding season is reasonably cool/ cold here
> 
> off to research connectors and switches..


bFlex is fully programmable so those settings won't be a problem. I have the 1A version in my MtbMacgyver light and use 100% and 50% settings to keep it simple. At 50% there is hardly any heat but 100% gets quite hot rather quickly. 1.5A would be even hotter and wouldn't really recommend this unless you absolutely need to. Adding an additional LED would be much more efficient if more light is desired. I would highly recommend the bFlex driver though. I wish he would make it a bit smaller though, <20mm would be fine.

Here is some good test data on the XP-G R5 (just remember to double the voltage and Wattage for two LEDs):









https://www.candlepowerforums.com/vb/showpost.php?p=3115908&postcount=354


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## mattthemuppet (Jul 16, 2004)

thanks for the help and corrections everyone, they're very much appreciated.

Sadly I couldn't find a single place in the US that had both Reginas and XP-G R5s (the Reginas being the limiting factor), so I ended up ordering the Reginas from Digikey (thanks for the headsup slcpunk!) and XP-Gs from LED Supply. I ordered 3 of each, which should come to ~$40 total, at least $10 cheaper than Cutter. Reginas are on back order, so I won't see them for a couple of weeks, but at least that'll give me time to start on the housing.

Waiting to hear back from taskled on a few noob questions about the driver before ordering, then it's off to Home Depot at the weekend to get some square alloy tubing (amongst other things).

I've figured a relatively simple way of adding a 3rd XP-G if I need one (given the advice above about running 2 at more than 1A) - leave the wires to the driver a little long, then all I have to do is cut a C section of tubing as long as my housing is deep, bolt a mount to the side of the original housing and JB-Weld the C section over that with a end piece to seal the back. If I drill a couple of holes in the original housing to wire the 2nd LED to the 3rd, then loop the wire back to the driver, I'll be golden  It'll be a bit of a hack job, but it's not like I'll be going to the DIY lighting equivalent of SEMA with it..

As soon as I get all the bits together I do a wiring diagram to make sure I'm not making any stupid mistakes


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## slcpunk (Feb 4, 2004)

nevermind...delete....


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## mattthemuppet (Jul 16, 2004)

small update:

3x XP-G R5 arrived from Ledsupply ($30)
3x Regina reflectors arrived from Digikey ($6)
Bought some JB-Weld ($5?), Lexan sheet ($3 or 4), odor free silicon ($3?) and 1in square alloy tubing ($?) from Home Depot.
Ordered a Magicshine extension cable (to cut in 1/2 for the male and female plugs), from DX ($3) plus a 18650 charger ($7) to try out the 18650 recycling method described here. Already have 2 laptop batteries, waiting on another 2 

Just have to wait for the b2flex to become available (a week or 2), figure out what gland size I need and get a switch.

Speaking of which, anyone know what the OD of the Magicshine cables are?


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## mattthemuppet (Jul 16, 2004)

another Q before I forget. The Reginas have a couple of prongs at the end - do people cut them off and stick the reflectors on with a dab of silicone OR do they drill holes for the prongs?


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## mattthemuppet (Jul 16, 2004)

*to heatsink or not to heatsink, that is the question*

so, just finishing up making the housing (pics to come) and I have a small quandary.

With everything bar the cable/ connector + lexan cover sheet, it currently weighs 72g without any extra heatsinking (so say ~82g finished). However, if I add the 2 heatsinks (1 either side, cut from an old CPU HS) I gain ~30g and ~3000mm2 (4.65sq,in) of surface area.

I'd like to run the XP-Gs at 1200mA max (with 350 and 750mA as the other modes) through the b2flex, with the option of running at 1500mA if battery life allows, so the heatsinking would come in useful. However, I'm not sure if the weight gain is worth the extra lumens. By point of reference, my current light is 140g all up and definitely noticeable.

I have another HS (old northbridge one by the looks of it) which weighs ~9g and adds ~955mm2 (~1.48sq.in).

Currently, mounting bracket not included, the light housing has an area of 8115mm2 (~12.5sq.in). So I could have either 8115mm2/12.5sq.in (82g) OR 9700mm2/ 14sq.in (91g) OR 11115mm2/ 17.15sq.in (111g) to dissipate ~9W (1200mA) or ~11W (1500mA).

what do you think?


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## mattthemuppet (Jul 16, 2004)

*nearly finished*

first, I have to start with my lovely new alu vice guards










then, the front housing pieces










with a recess ground for the lexan cover










3 sides of the each front piece are cut off










and the finished parts JB welded together










a piece of lexan is cut and carefully sanded to provide a press fit (the recess needed recessing a bit more). The recess in the recess was initially cut to JB weld a nut so I could bolt the lexan cover in, but in the end it fit so tightly that it barely came out even when I wanted it to.


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## mattthemuppet (Jul 16, 2004)

driver housing and helmet bracket made - the bit on the housing is JB welded there. The idea for the bracket is to stick a bit of velcro to the bottom of it and a complementary bit on the helmet, then thread a velcro cinch strap through the side to make sure it's tight. I don't know if the bracket will end up being too flimsy, time will tell..










the main bits assembled, before Harry the Hairy Heatsink was added (see  here )










I was told bluetac wouldn't be very permanent, so don't worry about that 

wire holes and star mounting bolt holes tapped










and Harry the Hairy Heatsink JB welded on. Don't know how good the heat path is, but it warmed up while I was cutting the channels in the housing just not as much as the housing itself.










nuts being JB welded into the housing. The first time I only used 1 nut and the torque of the bolts unstuck them. Second time round I used 2 nuts each side and more JB weld, fingers crossed they'll hold ok. I'm hoping that just 2 bolts will be enough as it all fits together pretty tightly, time will tell..










stars mounted a la Troutie's  Hammond light 










lexan cover siliconed in place - can't remember the name of the silicone, but it's one of those acetate free ones (and boy is it nice to use in comparison)


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## mattthemuppet (Jul 16, 2004)

*now the electronics - eek!*

now I'm onto shakier and more screwupable ground

here's the b2flex driver with all the gubbins soldered on (some embarrassingly badly). The bit of bent alu is JB welded onto the potting pad and will be JB welded to the inside of the housing. I couldn't think of a better way of doing it as the driver doesn't sit flat










as you can see. It was also a royal sod to get in there - adding the nuts afterwards would have been an exceedingly good idea










here's a rather nice illuminated waterproof(ish) switch. Note how my soldering is much neater. Part of that is because I soldered and heatshrinked it _really_ nicely, then realised I'd forgotten the bloody waterproofing seal. Many choice words were spoken (actually, the same one, over and over again)










the nut was a bit of a sod to get on. I spent about 20 minutes fiddling with it, went to watch Harry Potter, then came back and screwed it on in about 30s. Magic

Obviously, the fact that I was shattered and it was past midnight (and my bed time) couldn't stop my OCD, so I soldered the other half of the magicshine extension cord to a spare 13.2v NiMH battery pack et voila










It works! Stone me cold with a haddock, I was amazed.

Now I just need to fit the reginas, finish trying to paint it so it doesn't look like it's from someones rubbish bin and screw it all together. The power cable also needs silicone sealing (what was it you need to do so silicone sticks to plastic cables?) and the strain relief bracket bolted on. Just have to wait until I get back from my Thanksgiving holiday <itch itch>


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## odtexas (Oct 2, 2008)

Some serious time went into that light. 
Looks good. Did you cut each heat sink slot on the body with your dremel? 
Slots look really good and uniform, so however you did it, good job.
A trick picked up recently is to fit your lexan. Mix up a small bit of 5 minute clear epoxy. 








You can get it at Lowes or Home Depot.
Then work a small bead all the way around the junction between the lexan and aluminum body using a tooth pick. Have just enough epoxy to seal maybe 2 to 4 mm at a time. It takes a bit of work to spread the epoxy all the way around, but you will end up with a water tight seal and a real clean look.


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## klynk (Apr 18, 2010)

mattthemuppet said:


> another Q before I forget. The Reginas have a couple of prongs at the end - do people cut them off and stick the reflectors on with a dab of silicone OR do they drill holes for the prongs?


Cut them off and glue'em to stars.


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## mattthemuppet (Jul 16, 2004)

odtexas said:


> Some serious time went into that light.
> Looks good. Did you cut each heat sink slot on the body with your dremel?
> Slots look really good and uniform, so however you did it, good job.


thanks for the kind words, I appreciate it  I didn't keep count of the time I spent on it, probably 2-4h every night after the kids went to bed for 2 weeks. Each slot was cut with a Dremel, once I got the hang of it it wasn't too difficult. Each slot was started as a series of dip cuts in a line, then several deeper passes to join them up. Slightly nerve wracking at times though..



odtexas said:


> A trick picked up recently is to fit your lexan. Mix up a small bit of 5 minute clear epoxy.
> Then work a small bead all the way around the junction between the lexan and aluminum body using a tooth pick. Have just enough epoxy to seal maybe 2 to 4 mm at a time. It takes a bit of work to spread the epoxy all the way around, but you will end up with a water tight seal and a real clean look.


neat tip, thanks! I have at least 2 more lights to do, so I'll check it out for those. The lens doesn't look quite as bad as in the picture though, as it dries clear, but it could be neater!


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## mattthemuppet (Jul 16, 2004)

klynk said:


> Cut them off and glue'em to stars.


thanks klynk, that makes sense. I hate drilling precise holes with my drill as the bit tends to wander, even with punching a guide dent (?), so this is much easier.

hopefully I'll get this together in time for my Tuesday night bike ride :thumbsup:


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## mattthemuppet (Jul 16, 2004)

reflectors siliconed in place (might stick a bit more around the base when they're set tomorrow). Power cable sealed with silicone and bolted down with a strain relief. Free internet cookie to anyone who can guess what the metal bit is I used  Bit of plastic poking out of the housing is a vacuum cap wedged in to hold the driver in place while the JB weld cures.










tomorrow night is bolt everything together, program the b2flex and if I have time I'll do a timed run down with my new 11.1V Li-ion pack. Then it's first ride time on Tuesday  I think I might take some spare Li-ions and my old light with me, just in case...


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## savagemann (Jan 14, 2008)

Looking good man.
Looks like you used a disc brake shim as a strain relief....= )
I'm about to start a similar project myself, but I'll be using cheap DX stuff.


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## mattthemuppet (Jul 16, 2004)

ah, dumbass Q. With a 11.1V (3 cell) Li-ion battery, what is the best value for Vcut (to protect the cells) and Vlow (say 20% remaining)?

You'd never guess I'm more than a little intimidated by programming the driver...


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## mattthemuppet (Jul 16, 2004)

savagemann said:


> Looking good man.
> Looks like you used a disc brake shim as a strain relief....= )
> I'm about to start a similar project myself, but I'll be using cheap DX stuff.


thanks savagemann, everything set perfectly this morning and slotted together nicely 

99% correct on the disc brake shim - it's a safety thing to connect 2 disc brake bolts together that I got years ago with some Torx bolts. Never had a use for it until now!

I'll be putting a parts list and dimensions together to make things a little easier, though I would *strongly* recommend the b2flex driver, it is simply bleeding amazing. Just one example - I want 3 power modes (standing around/ road, climbing, DH) but cycling from low to high via medium can be a pain. Sooo, I'll be using the trimode function - click to go from low to medium, then each subsequent click will cycle between medium and high, with a short press to go back to low. How cool is that? Add on the battery protection and low battery warning function, plus overtemp and reverse polarity protection and the $38 ask doesn't look so bad. Don't get me wrong, my wallet flinched a bit when I paid for it, but I don't have a single regret :thumbsup:


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## mattthemuppet (Jul 16, 2004)

before I forget, here's your cookie savagemann


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## Homebrew (Jan 2, 2004)

mattthemuppet said:


> ah, dumbass Q. With a 11.1V (3 cell) Li-ion battery, what is the best value for Vcut (to protect the cells) and Vlow (say 20% remaining)?
> 
> You'd never guess I'm more than a little intimidated by programming the driver...


From the voltage curves I've seen on CPF from 18650 tests, voltage drops extremely quickly below 3V and it doesn't look like there is any significant runtime after that so that's where I would stop. Lucky for me, my friend MtbMacgyver programmed my bFlex with his preferred settings so I didn't have to figure it out for myself. Unfortunately that also means I haven't taken the time to learn it for myself.

BTW, excellent work!!! I made a similar double achesalot design light last week but still waiting on a switch to finish it up (maybe tonight). You did some nice extras with the heat sink and the cuts but you may need that running over 1A. I'm just using a cheapo single mode 800mA driver for this one and using Ledil CXP-RS square optics. I'll post mine up as well (hopefully with beamshots) when it's finished.


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## mattthemuppet (Jul 16, 2004)

thanks Homebrew, I appreciate the kind words 

I've just sent George an email, so I'll see what he recommends, but I'll put in a 9V Vcut if I don't hear back from him by tomorrow. I'm ever so slightly anxious about the battery as the cells are salvaged from dead laptop batteries and even though they've held their voltage for a couple of weeks, I still have no idea about remaining capacity


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## mattthemuppet (Jul 16, 2004)

just heard back from George (his customer service is worth the price alone IMO) who said to take 3/4 of the value for the 4 cell pack. After smacking my forehead, these work out to 9Vcut, 9.8Vlow and 10.7Vmed.

Now I just have to wait to finish work... <twiddles thumbs>


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## mattthemuppet (Jul 16, 2004)

*finally, it is finished*

headlight weight, a fairly reasonable 90g (cue EVA saying WAAALLEEE)










battery weight, of unknown capacity, a slightly surprising 189g (thought it'd be lighter)










and, finally, lighting up my microscope (out of shot) and keeping my coffee warm










I haven't had a chance to try it out yet and my ride tonight looks like it'll be rained off, but it does a fantastic job of lighting up support alcoves and blinding students

It's currently set to Threemode (low>[med>high]) at 350mA, 750mA and 1200mA, with Vlow warning (I really wouldn't want it to cut out in the middle of a DH), set to UIB2Q with 70C temp cut (it was supposed to be 60C, but I clicked instead of pressed by accident). When I get the chance I'll do beamshots with all 5 power levels and post back with ride impressions.

Now, onto the next light!


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## cncwhiz (Sep 8, 2010)

Lookin good man


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## mattthemuppet (Jul 16, 2004)

thanks! It'll look plenty scruffy soon enough (never painting a light again, PITA). Besides, my last light was made out of the bottom of an alu shampoo bottle, so aesthetics aren't my highest priority


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## mattthemuppet (Jul 16, 2004)

had my first ride with it last night, dialed down to 1A max (recycled laptop batteries don't have the highest capacity, it turns out) and I was simply blown away. Did most of my riding (extremely rocky singletrack) on medium/ 750mA, the fireroad climbs on low/ 350mA and the scarier DH on high/1A. Medium was pretty much fine for most of the trails, though obviously high was better 

Didn't have any heat issues at all, other than retaining feeling in my toes - it was 29F and snowing!

Unfortunately, even on high the light didn't stop my wheel dropping between 2 head sized rocks and flipping me over the bars. Landed on my arms and took a rock to the chest, so now I look like someone's attacked me with a belt sander. Even worse, both the brake lines to my levers snapped off, so I had a mile ride back to the car using a foot brake 

Guess it means I need another light...


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## cncwhiz (Sep 8, 2010)

I never even thought of adjusting mine. I just ride with it on full power at all times.


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## mattthemuppet (Jul 16, 2004)

when I get some new batteries I probably won't worry about using medium much, but sometimes it helps to have a slightly lower output so trail details don't get bleached out. low is very useful though, for trail side stuff and not annoying co-riders when you're talking to them or other road users.

besides, bells and whistles are there, so they must be used!


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## cncwhiz (Sep 8, 2010)

Oh I understand, I'm just saying. I never really even worried about something being bleached out either. I do see the advantage for the other reasons you mention though - interaction with other riders and such.


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## mattthemuppet (Jul 16, 2004)

*finally, some beamshots*

these aren't the best (very bright moonlight and patches of snow), but they'll give you some idea. I did the shots at 2s F3.2 (no idea on ISO, probably auto ) rather than 6s as even a single XP-G (next thread) was washing out the picture. Test is at 6s to give you an idea how much ambient light there was.

Bucket is ~10m away, mini-barn thing is ~20m and the tree behind it probably another 3m. Unfortunately the ground slopes away a bit, but as it's my neighbour's yard I can't really complain!

test









Cateye EL320 commuter LED light (soon to be retired!)









350mA









750mA









1A









I'll get some 1.2 and 1.5A beamshots when my new cells arrive sometime next year 

BTW, I'm liking this light very much  , though I'm dreaming of a dual XM-L bar light for early next year


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## mattthemuppet (Jul 16, 2004)

small update.

One of the reasons behind using screws on the stars and to hold the body together was to allow upgrading to newer/ better LEDs, especially as it takes me so long to make the housing.

So, I upgraded one of the XP-G to an XM-L T6

as it was









with the XM-L









boring out the Regina to 7mm to fit over the bigger LED









and done









took about 30min all told and pretty much cost neutral as I used the XP-G in another light..

no beam shots yet as it's either been snowing or raining or I've been building stuff out of wood for a change  The light is slightly brighter and the centrespot slightly wider (a good thing for me), with a more gradual transition from superbright to bright to spill.

This'll probably be it unless I get the itch to do a single XM-L sled light for the helmet or a new LED comes out in a year or so.


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