Cheapy fix/LED conversion

[closetleftie]

Now then,

I bought a Light& Motion commuter halogen from someone at the old place. Decent light, but the pins to connect the battery have given up the ghost. The housing & optics are OK, though, and takes MR11 bulbs.

Being a cheapskate and fancying some shed time, I thought:

1. LED MR11 bulb

2. Maplins (or something similar) battery holder & half a dozen AA cells

3. Insulation tape galore

Is this likely to be a waste of time? And if not, which LED bulb should I get? Could I end up with something that fries eyeballs ?

[bikenerd]

How handy are you with a soldering iron?
You can get little cups that hold a star-mounted power LED and then fit in an MR11 case.
Here from led-tech.de.
You could then mount a power LED (on a star mount) such as the Seoul P4.

You could then solder it all together, with a switch and battery connectors.

You should really use a current controller such as a Buckpuck type device.

Stick some old heat sink from a computer on the back of the cup with thermal conductive adhesive.

You could just use a ready made "household replacement bulb" like MR11 at ultraleds but it won't be as bright as the above.

[PhilO]

How handy are you with a soldering iron?
You can get little cups that hold a star-mounted power LED and then fit in an MR11 case.
Here from led-tech.de.
You could then mount a power LED (on a star mount) such as the Seoul P4.

You could then solder it all together, with a switch and battery connectors.

You should must really use a current controller such as a Buckpuck type device.

Stick some old heat sink from a computer on the back of the cup with thermal conductive adhesive.

You could just use a ready made "household replacement bulb" like MR11 at ultraleds but it won't be as bright as the above.

FTFY. 

That MR11 housing looks useful - I wasn't aware of that. With one of those, you could mount your LED in a Lumicycles housing and get a very neat lamp. But if you don't hav a particular housing in mind, you can just glue the star directly to a heat sink an add optics over the top.

This is an off-road lamp I made for a friend, using 2 P4s, a 1000mA buckpuck and 10 degree optics:



And this is a commuting lamp, which uses a P4 driven at 350mA and a wide-angle lens:



I have a similar lamp to the second as a helmet lamp, running at 1000mA, and a 3x3w Luxeon unit on my commuter bike, but I don't have pictures of those.

I bought the optics and controllers from http://www.ultraleds.co.uk/, and the P4 stars from http://www.dotlight.de/.

If you want to do it the easy way, though, I reckon one of these attached to the handlebars, and a 12v battery pack*, would be the way to go.

*NB. I solder my battery packs together. I used battery boxes with spring contacts for a while, but couldn't get them to work reliably with the vibration. I do ride off-road a lot, though...

[bikenerd]

And here's a (hub) dynamo LED powered set I made (must work on the sealing / replace the cracked plastic over lens):


PhilO: how did you make the housing on the first picture, the MTB light?

[PhilO]

PhilO: how did you make the housing on the first picture, the MTB light?

I've been meaning to do a how-to article for a while, so look lots of pictures of the process*, but briefly, it's an aluminium box bought from Maplin, with a strip aluminium bulkhead glued in place using thermally conductive epoxy. The LEDs are glued to the front of this and the buckpuck and a switch live behind it.

*I don't have these online anywhere, but I can email if you're interested.

[Tom M]

May well have a Commuter knocking round in the shed somewhere if you need any spare bits.

PM me if you wish.

[Tom]

PhilO, I've got a lumicycle-style lamp with a standard MR16 halogen bulb.  The burn time is pretty naff with an oldish 2000mAh 15.6V pack, so I was thinking of going for a Cree or Seoul P4 led.  Is it vital to go for a buckpuck and, if so, is the wiring fairly straightforward?  Are there any other gizmos that I'd need to get it running well?   I'm reasonably handy, but a bit kack-handed with a soldering iron...

Thanks a lot for any advice that you can offer,
Tom.

[PhilO]

Firstly, yes you definately need a buckpuck. Wiring is simple: +/- battery in, and +/- LED out. Input voltage can be anything from 5v - 32v. If the output polarity is wrong, the LED will fail to light, but won't be damaged. I understand that getting the input the wrong way round can cause smoke signals, though... 

The other thing you need is a heat sink. LEDs don't like getting hot. My lamps all use the smallest Carclo optics, which fit inside a 22mm copper plumbing fitting. You could do the same, but getting the heat from this to the housing might be difficult. The adapter cups which Bikenerd mentions in his first post look ideal (assuming that your lamp uses MR11, not MR16 bulbs). The LED would have to be glued to the cup using thermal epoxy (not the more common thermal compound, as this doesn't set), and then the optics fixed to the front. Job done. 

If you unit is sized for MR16 bulbs, you could use the larger Fraen optics and fit three LEDs. 1 buckpuck will be able to drive all three.

Another option would be a Cutter LED Kit. I've no personal experience of these, but have heard positive reports via the Singletrack website.

If you want more info, feel free to PM. As I said above, I must get round to doing a 'how-to...'.

[Tom]

Thanks a lot for this.  Mine's an MR16 fitting, so I may go with the fraen set-up, although it all seems a little more complicated than I'd thought...  Thanks again.

[closetleftie]

Thanks a lot for this..............although it all seems a little more complicated than I'd thought...  Thanks again.

Ditto!