6 R2 Bike light

ledgend lights

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Oct 16, 2008
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I've been working on this for a bit now i was going for 7 R2's but couldn't find an adequate way of driving them, not without using 2 bflex drivers. So i've had to settle for 6 for the minute running @ 1A.

I'm using a maxflex driver at the minute but it's being pushed to the limit. It was powered by an 11.1v pack but the IC kept getting to hot so i've changed to a 14.8v pack for now until i can find an 18.5v for the right price.....anyone know any where?



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It's still a little rough around the edges but it's only a prototype.


This first night shot is with a 25º lens
3057820609_014887bf26.jpg


It just threw the light every where, but not very far down the track, this next one has a much tighter 8º lens which i think is much better.

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The person in the photo is 50m away, the side spill from the light is plenty even with the tight beam angle.
 

znomit

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I've been working on this for a bit now i was going for 7 R2's but couldn't find an adequate way of driving them, not without using 2 bflex drivers..

Wow, nice light. The clear dome at the back is a nice touch.

Wont the maxflex drive 7 R2s? The newer R2s are around 3.3V or less at 1A so 7 is only 23V
 

ledgend lights

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Thank you, the clear dome is so you see the STAT led.

I'll have to look into those newer R2's, the only problem with that is i'll have to get a 22.2v battery then. Because if the driver is running too inefficent less that 95% at this high an output the IC gets too hot and cuts out.
 

dom

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Nice job LL
Have you got the pad on the maxflex thermally connected to the body?
You have great heatsinking fins there.

Cheers
Dom
 

ledgend lights

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Thanks dom,

Yeah it's conected using a small block of aluminium wiht AA on both sides.

I spoke to george at taskled and he said i was running to inefficent and had to up the input voltage, thats why i need an 18.5v pack.
 

LED_Thrift

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That looks beautiful! It's so small and yet so bright. Nice fins. The beam looks great - very useful for mtn biking.

Thanks for showing this to us.
 

piesoup

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Fantastic light! I thought I was pushing the boat out with 4 R2s! Are you able to post pics of the assembly of the head? Do you screw the head onto the body?
Thanks!
 

Phaethon

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Looks great!!!!
I have a 22.2V battery and charger, from a canon portable photo printer , bought them as spares! It's a BCA-CP100. Only 1200Mah but quite compact.
Do you intent to build more than one?
 

ledgend lights

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.......
Do you intent to build more than one?

Yes, i plan on making them to sell when i'm happy that everything works. (A few more weeks of nightriding)

When they are ready i'll be taking pre-orders of 10+ before i order in the components.

not sure on the price yet was thinking about £270ish if i can get the battery and charger at the right price.
 

ledgend lights

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photo's of the assembly, sorry there a bit later than i said.

This isn't the cree R2 assembly, it's an SSC P4 one i used for testing. I didn't want to open up the R2 unit up as i've sealed it, but every thing is the same apart form the LED's on the board.

You will note there are 7 LED's on the board i've put a wire on to bypass one of them as the Vf would have been too high for the maxflex. I'v done the same thing on the R2 board aswell untill i can get a definative answer on what the Vf on R2's is @ 1A.

3096862563_5e50be03b4.jpg


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znomit

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Is that the 7 cell polymer optics cluster and does the black holder come with it?
Also instead of bypassing one LED run 2 in parallel for a few more lumens.
 

ledgend lights

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Znomit,

yes it is the 7 cell polymer optics. No the black fitting around the edge doesn't come with them it's made by the manufacture i'm going to get to build my lights.

I'll have a look in to running 2 in parallel but the way the board is designed it's easier just to run 6 for now untill there is an LED with a lover Vf or a different driver option, but it's still worth looking at as it will give a 50 lumen increase.

Anyone know when cree are releasing their data sheet for the R2??????
 

Phaethon

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I'd be interested in one unit, maybe two , no battery and charger needed, if the price is right.
May i make a "small" suggestion, it might be better if you can position the mounting bracket a bit closer to the centre of the light, by machining down the fins in the lower side where the bracket sits. This way, the light won't protrude as much from the handlebars, which is crucial for tight singletrack ridding. If you look at the latest designs by hope, lupine etc you will notice that they try to make devices that clamp on the hadlebars with little profile...... :naughty:
Good luck!
Fotis
 

ledgend lights

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Fotis,

I've looked at mounting the bracket closer to the front of the unit and closer the the centre but that creates problems taking the bracket on and off the bike also extra machining on a mill and i havent got one of those and doing it on a lathe wouldn't be easy, so i'll be leaving it as it is for now. Thank you for the input.

For the unit including LED's, Maxflex, swithch, clamp, lens and acrylic cover on the back i'd be looking for about £160 + P&P. It will be sent out with one of the LED's bypassed so will only run on 6 and you'll need an 18.5V battery to run it at 1A other wise the IC on the maxflex gets too hot and cuts out.
 

worldedit

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Jul 4, 2007
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Id recommend to use two of those in series:
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7346
These are transmitter packs so they wont deliver 60A, but it seems like 5A is plenty for your light. I assume you got a Li-ion pack so far. Lipo cells are a bit more risky than Li-ion but you can buy a fireproof bag for them.

A cheap way to charge them is:
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7898
is would charge the 2 packs one by one in about 5 hours.

I use this charger for everything but single AA batteries:
http://www.hobbycity.com/hobbycity/...ame=Turnigy_Accucel-6_50W_5A_Balancer/Charger
Still pretty cheap and works very well for me. It would charge both packs at once. You need an adapter though.
 
Last edited:

Phaethon

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Fotis,

I've looked at mounting the bracket closer to the front of the unit and closer the the centre but that creates problems taking the bracket on and off the bike also extra machining on a mill and i havent got one of those and doing it on a lathe wouldn't be easy, so i'll be leaving it as it is for now. Thank you for the input.

.....................

Ok, then may i suggest that you reduce the total diameter of the fins that are close to the mounting area? This way you need no mill. I also like this mount from lupine : http://s235041100.online.de/shop/ar...unt-31,8-mm.html?shop_param=cid=121&aid=i789&

For batteries, you could also look at external laptop power stations. I have a polarmate 16/19V li-ion pack (it's pretty big though) and a more compact 14.8V from dealextreme.
I have built a light with an osram ostar 1100lmns led, powered by maxflex, but no longer have access to a lathe to make some extra modificationjs i need.......:candle:
Let us know when you put these in production and whether you will opt for the 3.3V leds.....
 
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