LED spotlights ??

[Sibbo]

Wow ! Thanks ,thats precisely what I needed to hear .I suppose from that I should never by a spotlight except on the recommendation of someone who really knows what were looking for ! I'll certainly pass on the Ebay ones posted above .

[Major Softie]

But they might be GREAT, and now we'll never know.

We didn't want you to not buy them, we just didn't want you to be able to say "why didn't you tell me?" We actually WANT you to buy them, be the guinea pig, and then we'll know if they're a waste of money with absolutely no risk to ourselves.

[Sibbo]

Umm ,I'm my own guinea ! Far too often .

Another question ? Were I to be buying some hypothetical LED spot lights how many lumens equates to say ,a halogen 100w spot ? I understand that the reflectors are a large part of a light's efficiency but can't see how that can be specified in an ad ...at least in terms that the dumb consumer (me) can understand .

[Major Softie]

A 100w H4 lamp produces around 2500 lumens (note the 25 lumens per watt). Most stock 60w/55w H4's are producing a little better ration than that: around 1650 on hIgh beam.

[Sibbo]

Thanks Major , it's gradually becoming clearer .... You mentoned above that LEDs will give between 4.5 and 150 lumens per watt ! Halogen gives 25 .Ideally LEDs should be far better .
It's going to require careful reading of the specs ! To have a dimable LED spot would require double the number but differently aligned within the reflector shell ?

[Major Softie]

It's going to require careful reading of the specs ! To have a dimable LED spot would require double the number but differently aligned within the reflector shell ?

I don't know if there is any current solution to that issue. In the theatre, LED's are becoming more popular, but they are strictly "wash" instruments: lights that provide a general soft wash of light. 1000 watt Halogen instruments are the very common "standard" instrument in the theatre. Their lamps are putting out around 27500 lumens. Optics that focus a tight beam of light are generally designed around a single source point. Since we don't have any 200 - 300 watt LED's (which could possibly give us the brightness of a 1000 watt Halogen), all the bright LED instruments are designed around huge arrays of many LED sources. To a lesser extent, we have the same problem trying to create an LED headlight.

[The Bigfella]

Its OK, I'm the guineapig on these ones. I've got 4 of the 27w non-dimmable versions of the ebay ones that left Hong Kong today. I'll use them for something else if they aren't any good for the bike (eg boat)

[The Bigfella]

Well, the lights arrival appears to be imminent, according to the tracking... but I've just bought a dimming trim pot to go with them.... and its coming from the States.

http://cgi.ebay.com/ebaymotors/Dimmer-s ... ccessories



A guy over on ADV suggests them and his comment was:

the dimmer lets you set whatever brightness level you desire at the time, however, flicking on the Hi Beams will bypass the the dimmer, switching the LED lights to full brightness. I believe this can be done with a simple/standard 5 pin relay. The functionality of turning the LEDs on from an On/Off switch or together with the Hi Beams will be done via a SPST switch (mode selector).

[The Bigfella]

The lights have arrived today from Hong Kong - they took 7 days to get here, which is fine by me. Well packed and they look good. I hooked one up to a 12v battery in the shed and bloody hell, they're bright. They'll certainly do the job as "look at me" lights. I'm flat out with work at the moment, so won't get to do more than shine one around the backyard - until I get a couple of (work) projects finished. I've got (or had) a decent multimeter that measures current draw.... it'd be nice if I could find it.

The only branding on the lights is on the wiring tail (about 3/4 metre long) and it says Kehuan Electric. The mounting bracket is stainless and there's a handlebar mount included.

More later

[StephenB]

Its OK, I'm the guineapig on these ones. I've got 4 of the 27w non-dimmable versions of the ebay ones that left Hong Kong today. I'll use them for something else if they aren't any good for the bike (eg boat)

Hey bigfella, what's the auction ID# or seller's name for those 27W LED lights, I'd like to look at them.

Thanks, Stephen