suggestions for higher power white LEDs to testing?

I've had good results with:

I got some piranha style RGB leds and some "straw hat" style 100 ma white leds - the straw hat ones are at their limit with 100 ma going through them - one set lasted for a few months (dawn to dusk - fine in winter dead or dying in summer. Reduced the current to 50 ma and they are good year round.

That was _almost_ my case. My products were backordered for some time and eventually I decided to send a message asking what is going on and when the backorder would be released. More time goes by (month more? that, after a previous 6 weeks of delay) and I get a message about "would you like to get something else?" Dialog is very slow (language?) and it took still more time to begin to understand that they intended to keep the money no matter what and not make it easy, either, to put it onto some other order. I still don't know how that gets done.

And, I suppose, I've become less interested in finding out.

Jon

Okay. I've often wondered about aging issues. So that's good to know.

When high power is the primary goal of a product, often other goals are sacrificed on its alter.

I'll take a look on Shop4leds on ebay, too, then.

thanks, Jon

I see you don't realise the disadvantages of use life-expired components. I bought new parts for the vast majority of my hobby projects.

Graham

WTF are you talking about ?

Graham

Besides the fact that these are kids, Graham, it is exciting for them to do something useful and fun with parts their parents throw away. Kind of a segue to more. And it often impresses their parents, which may for some excite them towards further effort. And I can always help them at that point, if they are interested in doing more.

I am on the ground, spending _my_ time in the trenches with kids, Graham. I am dealing with what I have to work with. If you'd like to come on over and help out, I'm all for it. And I'd value your opinion on this more, then, because of your direct experience with my situation.

What are _you_ doing, Graham, to pass on your knowledge and interests to children?

Jon

Without the battery or LED, three parts. You didn't follow and I guess we can leave it there, then. :)

Jon

Maybe Graham is just saying he was born with a silver spoon in his mouth. But I really think it is his failure to actually remember what it is like as a kid looking in, from the outside.

I didn't do much as a kid -- instead spending far more time on optics, explosives, rocketry and the like. Some others did and they eventually made career decisions and left me far behind in this regard. But I've always had a kids interest in electronics, as a hobby. Never had a single hour of formal training in it, though.

But I remember vividly building my first radio out of galena and molten lead, with a sewing needle, to make the diode. And all the rest involved, too. And making a jacob's ladder from a TV flyback supply. And calling up a bowling alley owner for permission to scavenge what I could from his building after it was hit by a tornado the day before, for parts. And tearing apart phone company throw-aways I'd get out of a dumpster behind their building. Etc.

I had no money, lived in a home without walls at the time, and had to get by without a lot that some living in better circumstances had access to.

It's possible that Graham has no idea about any of this and had everything pretty much handed to him.

Jon

You didn't answer my question.

What makes you think kids read Usenet, let alone even know of its existence ?

Graham

Yes

If they haven't been stressed in a high temp environment designed for a specific lifetime like a CFL they probably will be fine. By the way, when did you find either in a CFL ?

Why is buying new parts bullshit ?

I was dealing with authorised distributors already at age 16 and buying parts in quantity to get price breaks. My hobby had already moved to small scale manufacture.

Graham

Most higher power LED manufacturers quote lifetime at 70% of initial luminosity.

Graham

Hmm?

I'm talking about _personal_ contact here in my local area with real kids. I wasn't being serious about asking you to fly out here and help me. My point there was that if you were here, met the kids and saw the situation on the ground here, I think you'd follow a lot better.

Jon

Which provides a definition for one point. It doesn't say much about the different causes and the general picture or what one might expect in some specific situation.

Jon

Then you'll need to ask it better, I suppose.

Jon

If you are still interested in putting us in touch with each other, feel free to contact me, directly.

Thanks, Jon

Oh, If these might work for you, I could slip you a few in an envelope. I've got some other white LED's kicking around from a previous project, but mostly through hole, lower current ones.

There's a slush fund here where I put money for the parts/ supplies that I steal from work, so I can add a few bucks to help out the education effort.

I just sent $50 to the OSA for a Galileoscope project. Students get to make their own telescope. The $50 covers parts, one is sent to a school and I got one for myself (and my kids)

George H.

Well, if you feel that is okay. I had no problem at $2.50 ea, just the "100's" part of it. If you are willing to sell a few of them, I'm fine with that.

Or I can send it.

Hehe. Is this something akin to the "one laptop per child" thing, where you buy two and get one?

Jon