Outer Limits 4x4 Board

Something a bit different (although it's only really a 'prototype' to see how it would work out).

Cree LED (probably about 1 year old technology now. Approx $5 each.


LED Driver from Jaycar - can run up to 6 of the above LEDs. Approx $25.
Takes 9-30V DC input (i.e. car battery is fine)


An old piece of galv steel tubing with a few holes drilled in it, then the Cree LEDs attached with a bit of thermal paste in between (white paste). LEDs are wired in series. The tubing is prob the same size as most of the previous mounting tubes shown above.


Test run on the desk - looks pretty bright so far!


Stock 99 NL Pajero reverse lights. I popped the camera in manual mode with fixed iso/apeture/shutter speed to give an accurate comparison between the two lights.


The 3 LEDs !!! The carport is about 10-15m away.


Looking back at the car. Haven't made up a mount yet, so was jsut sitting on the spare tyre. LEDs up top and reverse lights to the side.


The best part is, the 3 LEDs draw about 7W total. The stock reverse lamps are 21W (EACH!) as a comparison. Could leave these lights running for hours without having to worry about the battery. And extra bonus of being tiny compared to a usual camp light. Could easily mount to the cross bar of a roof-rack without getting in the way.

Cost is about $45 for the LED and driver. Will need another ~$5 for a switch, and say $10 for the wiring and thermal paste. No rely is needed due to the low current draw. Although you may need a fuse depending on where you take the power from.

I'm pretty happy with the result, so now will probably order some of the recent model Cree LEDs (still about $5 each, but a bit brighter again) and remake it with a bit more care/accuracy. Might just wrap a bit of plastic around the front of it as a dome to keep the rain off, but can't see why a little splash of water will hurt toooo much...

(I posted this on the Pajero Club forum, but thought might be useful to some peopel here as well)

cree also do a MCE (i think is the model) which is a muilti chips led. basicaly those 3 led's all together in one package. commonly used in torches.

watch the moisture, that tends to kill them. need to make a cover etc so they stay dry.
also several lenses are available so you can focus them a bit more. from flood to reasonably tight. they are no no bigger then the width of the led board.

nice heatsink. if you are going to run them for any length of time a good heatsink is a must ie needs fins on it. that galve tube is a bit minimal. they do not get much cooling when they are not moving and can heat up. mind you at 700ma heat shouldn't be to bad unless stationary for hours. just watch you don't sit them next to another heat source.

day time can be a big problem. if the heatsink heats up in the sun and you go into reverse for a while it can be enough to cook them.
some controllers have a temp sensor and will cut down the power to the led's when they get hot.

Thanks for the tips/thoughts.

Yeah the MCE is a 4 die chip. Tempting, but the thermal issues you mentioned might becomes even more of an issue. Not sure on their prices either. Will look into it.

Didn't realise that moisture was a significant issue. Will have to look into some form of housing then. Bit of a bugger, was trying to keep it relatively simple.

I'm thinking on the 'finished' version if I make the whole mounting arm out of the same tube the LEDs are mounted too, it will be a MUCH larger heatsink. The heatsoak from day time hadn't crossed my mind though... The plan is to mount the driver in the door to keep it out of the elements, so even if it did have a temp sensor would be a long way from the LEDs.

Back to the drawing board!

Colour rendition can be a problem. I still prefer flouro's for this reason.

Colour rendition varies. Bluer is to be avoided. Yellower is better.

Nice job.

Paul

me3@neuralfibre.com wrote:Colour rendition can be a problem. I still prefer flouro's for this reason.

Colour rendition varies. Bluer is to be avoided. Yellower is better.

Nice job.

Paul

Could improve colour rendition (CRI) by mixing the 'tints' of the LEDs. Actually, something I will probably do now that you mention it. Thanks for the idea!

It'll always be a little 'cool' (blueish), but its not like I'm proofing a magazine print by this light. Just for knocking some pegs in the ground and cooking dinner. Still a good point though.

Hmmm, you have just given me a great idea. Even though I have modded the tail lights on my GU to have both reverse lights working, Im still not happy with the output.

I recently bought a flexible led strip light camping light, 12V with 144 LEDs per metre. I might look at installing a strip across the back step of the GU, as a reversing light.

EDIT, unfortunately, the shape of the GU rear bar doesnt allow this to work, it would on an older GQ one though.

Get yourself onto www.dealextreme.com - they sell lots of good DIY stuff for making high power LED lights and the prices are dirt cheap compared to local stores.