My search for LED rear lights that I like as too date come too nothing, found one or two advertised for trailers/lorry/bus type but now really what I
want.
Whats involved in making your own ?
Say I wanted a cluster of clear LED's that within them contained stop tail and indicator functions how easy/hard is this too do ?
Please remember I'm not bad with spanners but crapo with electronics ?
From my experience as long as you buy 12v led bulbs it shouldn't be too hard...simply a case of mounting them all and splitting them into the sections you want eg. half tail and half stop then wire them all together in their sections and out to a relay or the switch directly....I'm no expert but can see no reason why that shouldn't work....you might have to be carefull with regards to wattages etc as this will effect the speed of the flash amongst other things....Oli.
Just make sure you comply with the SVA lighting area rules.
12V leds are just 2V leds with a regulator of some sort. for automotive use, you should have something that will withstand 18V ro more for a short
time but still work, at least partially, below 8 or 9V. The last thing you want is to blow your lights on a dark road or have them go off when
cranking.
LEDs can be bought clear or self coloured in red, orange, yellow, green, blue and white. You can make all light functions for a car with them. They
are available in different viewing angles. The viewing angle is usually conical and usually between 15° and 45°. The brighter LEDs are brighter
because all the light is crammed into a narrow cone.
I would use a constant current source to regulate the battery voltage to drive the LEDs. I'd also check into the legality of driving the red
LEDs at 1/4 power for tail lights and full power for brake.
Do you need lenses for rear lights or is it OK if you meet the viewing angle restrictions. What about E marking. Could you cheat and hollow out an E
marked fillament lamp and stick your LEDs in it?
I realise the E mark could be an issue come MOT time just wondering what was involved and if it was a diy option for a numpty like me,
just thinking out loud.
The closest i have found too what I am looking for is these, they are E marked and have reflector built in.
Stop/Tail/Indicator.Image deleted by owner
This circuirt can drive up to 10-15 high brightness red LEDs
Note: The transformer and bridge rectifier and "battery" are not needed!..Incidentally this circuit is for a battery charger but it works
equally well as an adjustable DC supply. 2.4V--35V
Full details can be found here
[Edited on 20/12/06 by Fatgadget]
LEDs are constant current device. As previously mentioned you need to take note of an over-voltage situation (like being jump started by the 24v of an
AA/RAC van).. Other than that it's easy...
I'd put the in series up to 18v total forward voltage then in parallel. In my experience, LEDs will take an over-current for a minute or two
before breaking down...
The main problem with using conventional leds is that the brightest ones have a very narrow field of view and they tend to 'disappear' in
daylight. Simplest and best option imo is to use the latest Luxeon Star leds as ALL the other so-called replacement bulbs are absolute crap (and I
have tried most of them)
These little beauties are another story. I have been experimenting with diffusing lenses and have now installed them in my lights - even the reversing
lights.
One tip - if you use them in conventional light units, choose the same colour as the lense (ie red led for red lense) as the white variety gets
filtered out by a coloured lense.
As far as E marking goes, I seem to recall that the manual says it is ok to have anything fitted (no e marks) as long as it is deemed to be
effective.
[Edited on 20-12-06 by RazMan]
Rescued attachment 1157_3wled10.jpg
Check out 'LED1.de' on t'web.
If using high power LEDs make sure the heatsink is adequate.
Be careful when playing, sorry, doing developement. The 5 watt type are so bright they will damage your eyes if you look directly at them when
powered! 
this site might be of help: http://www.hidplanet.com/forums/index.php
but you first have to register look for the LED forum
Jon, once SVA is out of the way you should have no issues with the MOT. They tend to look for functionality. I managed to MOT with r/h dip h/lamps and a bit of tape and 'custom' motorcycle indicators with clear bulbs as side lights.
I've been thinking about this too, and with the advent of the cree xr-e led, LED headlights are also beginning to look distinctly plausible.
Check out this thread:
cree xr-e beam shots
Try the LED section of candlepower forums for people who've done similar stuff before.
LEDs do need a current regulator to work consistently, as their resistivity changes with temperature so a resistor limited circuit can not provide
constant current. The best / cheapest option I've found (building stadium power LED bicycle lights!) is the LM317 regulator (available from
Maplin). Very easy to set up and use.
What are the MoT rules, or where do I find them? There are lots of potential problems with doing headlights, but it could be very cool...
http://www.s-v-c.co.uk/SVCMIXMATCH.HTM
[Edited on 21/12/06 by stevebubs]
http://www.s-v-c.co.uk/SVCMORELIGHTS.HTM
95mm UltraBright LEDs
Stop/Tail
Amber Indicators
Rear Fog
£38 pair + £4 P&P
£45 pair + £4 P&P
£22.50 each + £4 P&P
quote:
Originally posted by Tricky Dave
LEDs do need a current regulator to work consistently, as their resistivity changes with temperature so a resistor limited circuit can not provide constant current. The best / cheapest option I've found (building stadium power LED bicycle lights!) is the LM317 regulator (available from Maplin). Very easy to set up and use.
quote:
Originally posted by BenB
LEDs are constant current device. As previously mentioned you need to take note of an over-voltage situation (like being jump started by the 24v of an AA/RAC van).. Other than that it's easy...
I'd put the in series up to 18v total forward voltage then in parallel. In my experience, LEDs will take an over-current for a minute or two before breaking down...
quote:
Originally posted by stevebubs
http://www.s-v-c.co.uk/SVCMORELIGHTS.HTM
95mm UltraBright LEDs
Stop/Tail
Amber Indicators
Rear Fog
£38 pair + £4 P&P
£45 pair + £4 P&P
£22.50 each + £4 P&P
I'd looked at these
http://docs-europe.electrocomponents.com/webdocs/032d/0900766b8032d17f.pdf
for the electric car - an array of 6 should be suitably effective for a slow vehicle + not waste too much battery!
I'd drive 'em with a current controlled switcher which would cost another couple of quid for every 2 lights. The lights are £3.60 each from
RS & they sell 2 different reflectors, a 'wide' (dip) and 'narrow' (main beam). They have to be heat sunk!
They look extremely effective in the lab - but that's no guarantee of 'on the road' effectiveness
Bob