Advice needed with luxeons...

There's a chance that I've put this post in the wrong section - if I have please could it be moved to somewhere appropriate! /ubbthreads/images/graemlins/grin.gif

I'm in the process of replacing my stop/tail lights on my bike with LEDs - I have tried some direct replacement LED lamps but they aren't anywhere near as bright as the original lamps so I thought I'd throw some luxeons in their place! People won't miss the fact that I'm braking!! /ubbthreads/images/graemlins/happy14.gif



This is my rear light housing that I'm working with, I've already added some amber 1W luxeons which are used as my indicators. In the remaining space I originally was planning on putting about 6 red 1W luxeons on each side but then once I'd settled down after looking at the price and also the thermal requirements I've now settled on putting 4 1W luxeons on each side. As well as the luxeons I'm also going to put in a small cluster (14) of 3mm LEDs on each side.

Originally I was going to mount all these on 3mm aluminium which in turn was going to be stuck on the biggest heatsink I could get away with - Now I'm thinking of mounting everything on 10mm aluminium which will be about 65x40mm in size but I'm not sure if I'll still need a heatsink? The cluster of 3mm LEDs will be at a constant level and I don't think I need to be all that concerned about the temp that these will run at, it's the 1W luxeons... I'm planning on running these most of the time at around 50% brightness (depending on the colour shift I get at that level - i may need to run them at a higher level I guess) but when I stamp on the brakes they'll be at full brightness - and that's where I'm not sure how hot they'll get - I reckon that they'll be at full brightness for a maximum of a few minutes while I'm sitting at traffic lights or waiting to make a turn. Will 10mm aluminium be enough or should I play safe and bolt on a heatsink? I reckon that once I'm on the move I'll get some airflow running through those holes meant for the lamps so that'll help with cooling.

One last thing, I'll be driving the 1W'ers with 2 luxdrives - one of which will be 'dimmed' and the other will be at full power - Am I right in saying that if I join both +ve leads from the drivers (after a diode on each lead) will I have problems with over current? I mean, if one lead is carrying 175mA but then when I hit the brakes the other lead will then supply 350mA will that mean I'll be supplying 525mA? - I should've paid more attention at school but that was close on 18 years ago! lol

Thanks in advance for any advice anyone might have and sorry if this is a bit long winded!

well, cler=ar alternatives sell some using 5mms here:

http://clearalternatives.com/

they work great, and the luxeons should do the job. You might want to look into DC-DC converters.

-David

Thanks for that link...But they don't do anything for my bike though. I think I may have seen that link before but I can't remember! I'm using a couple of luxdrives from leddynamics to drive the luxeons

welcome to cpf, what you need is two 140 lumen red/orange 3watt luxeon stars.

smitty244 had a few of these available red/orange luxeons

I did consider some 3w lux's at some point but I reckon they might be a bit OTT though!! I reckon those red/orange ones are the wrong colour too...I'd probably have a struggle convincing the MOT people to pass my bike. If anyone happens to know a cheapish place to get red 1W luxeons please let me know - RS prices are just ridiculous and Farnell aren't that far behind! The cheapest place I've found so far is Future Electronics but their minimum order is $500 so they are out of the question, but I have found a place in Germany ( www.dianaelectronics.de )that are fairly cheap but they don't appear to reply to sales enquiries though!

Problem- is that DOT legal?

I have made orders from futureelectronics and all of of them have been for less than 200US

I tried to make an order on Future earlier this week I think it was - because I'm in th UK I couldn't place the order online so they put a sales rep to phone me - that's when I found out about their minimum order plus they say they will only sell to companies - I'm self employed so I can get around that but I'm not sure I can get around the minimum spend!

Over here we have an annual 'test' for our motor vehicles over 3 years old - my bike doesn't need an MOT yet until next year but I hear they are fairly strict - the last thing I would want to do is spend more money next year to make sure my rear lights are upto spec! - Saying that there's a slim chance that even these homemade lights won't meet the spec..depends on how anal they are!

funkazoid, most red tailights are not pure red anyways.

the one's smitty244 has are BRIGHT! put those under your red lens and your good to go.

way brighter than a std bulb, almost too bright!

Funkazoid,

That wouldn't be a Falco tail light reflector by any chance would it??

Tim

Ok, red-orange luxeons look like normal incandecent brake lights anyways, as those aren't cherry red. You can use several 1W R/O that are typically 60lumens, or a few R/O LuxIII's that are typ 190lumens. Make sure the power going to them is regulated well and safe, and they are heatsinked good.

There is several people selling the LuxIII 190lumen R/O on here. PhotonFanatic, Ctechlite, smitty244, etc.

'ello Timson - You're correct it is a Falco unit! /ubbthreads/images/graemlins/wink.gif

My rear light lens isn't red I've recently changed it to a smoked one so I was going to chuck in some red lux's. I have to say I've not entirely convinced about my need for R/O lux's - I think I'll err on the side of caution and stick with the red ones. Not to say that I won't change my mind if anyone can convince me that is!! /ubbthreads/images/graemlins/wink.gif

I've been looking around at heatsinks and with the limited space I have it's been a pain in the arse trying to find suitable heatsinks! I've ordered, from Farnells, a heatsink that I will need to chop down, I know once I chop it the manufacturing specs go out the window. The link for it is here! I'll need to chop it down pretty much in quarter most likely to about 40mmx50mm. Will this be good enough bearing in mind I'll be mounting these lux's on 10mm thick aluminium and they'll be at about 50% brightness for most of the time?

Ta

I am not aware of any minimum in the US on Future purchases. I have placed orders for $ 50 just fine.

If you need some small qty, you can buy them through the sandwiche shoppe. Red / Orange is the correct color in the US.

I ordered $13 of parts from future. They slapped on an extra handling fee.

I've just finished making up one of the plates I'm going to mount my lux's on...And it's bloody heavy! Main question I have is do I really need a heatsink on the back?! I've chopped down a heatsink to fit but if I bolt that on I'm worried about the unit being too heavy to be secured in place safely.

I seem to remember reading somewhere that a 1W lux needed about 1 square inch of metal to act as a heatsink, by my calculations the plate I've made up will be just under 4"² and will have 4 1W lux's glued on - being 10mm thick I'm hoping this will be enough seeing that the lux's will be driven most likely at about 170mA ish for the majority of the time. At most they'll be driven at full pelt for a maximum of about 1-2 minutes whilst I'm waiting at traffic lights.

One last thing, I'm powering these lux's with a pair of lumidrive buck pucks. I'll have both outputs from these joint to a single cable but with diodes in line. Obviously the diode will have a forward drop ( I think the ones I have will have a max forward drop of 1.1v )Anybody know if this will affect the running of the lux's? I'm hoping that the lumidrives will 'see' the diode and pump out an extra volt or so but even so a dropped volt isn't the end of the universe is it?

I'm still looking around to source some lux's I found this place http://www.luxeonics.com anybody had any dealings with them? They seem to be fairly well priced and their delivery charges are reasonable too but knowing my luck I'll get hammered on import duty though! /ubbthreads/images/graemlins/icon23.gif

Thanks! /ubbthreads/images/graemlins/smile.gif