Step-Up, 10 watt, for LED-Array # I pay up to 50€$

Hi Forum!

i´m reading around here for a while, really amazing what you people do! and obviously a nice community as well!

my question(s):

i bought a damn expensive charger with 4 8000ma/h D-cell nimh´s for another project, which failed.. to have any use of them, i got a 2D mag. dissapointing, not useful for anything at all..

so i looked around, and wow, these 395nm led´s got dirt cheap. 100x 3mm led´s wouldnt be that expensive.
so i would like to install around 50 to 100 (78 i guess) 3mm led´s into that mag, and still use my D cells. at up to 10watts i would need a quite big step-up converter.. i surfed and read for several days, got more and more confused and tired, i gave up planning my own circuit.

is anyone willing to help? best thing of course would be if someone sends me a readily built circuit. the parts for it would be nice too, and just a circuit with a list of parts would help me alot as well. i will pay for it, of course. problem is, over here in germany chances to get some fancy ic´s are more than bad.

if someone has another idea what i could do with my 2D-mag and/or some D-nimh, i´d appreciate to hear it!

thank you,

manuel / krutzbeuazen

Re: Step-Up, 10 watt, for LED-Array

There's another solution to your problem other's than a circuit. But it would mean using AA batteries instead of D size batteries. Get some 3toD battery holders from elektrolumens (www.elektrolumens.com) under the flashlight hobbyist parts, have 6AAs in your mag, wire up the LEDs in series parallel of 50 pieces of 2LED in parallel, add a little resistance to them.

I don't think my idea is what you're looking for. Another way is to use Red Leds. Since they need less voltage than white Leds, I think they should light up on 2 D batteries.

Re: Step-Up, 10 watt, for LED-Array

(ah damn, no email-alert on new replies in this forum? hmm..)

yes, i had this idea as well, using several AA cells instead of the D cells.
would be less effective (resistor), would use less of the energy of the cells (a circuit should/could deliver usefull voltage when the cells drain) and i would have much less mA/h alltogether..

well, since there doesnt seem to be step-up-converter aviable with as much as 10watts, it´ll be my only chance i guess.

i guess i could try to find a converter meant to power 2 or 3 of the 5W lumileds, as another idea..?

anyway, if anyone has a hint for me, i would be more than happy!

thanks,

krutz

Re: Step-Up, 10 watt, for LED-Array

If you have a Badboy 1200, it might be able to push 10 watts to a single 5 watt LS. But the IC and the inductor will be running SUPER hot... Probably want 2 or 3 of those in parallel to make sure that the ICs don't toast themselves.

They are around $20 each I think. 4 D cells should handle the current draw just fine. Of cos you can use 3 BB700 and 3 5 watts. But... the price would get rather high I think.

Re: Step-Up, 10 watt, for LED-Array

NERDIE!!! /ubbthreads/images/graemlins/twakfl.gif

BB is not suited for HIGH drain application. I recall some talk regarding BB failure at high current (above 750 i think) /ubbthreads/images/graemlins/icon3.gif

will pay up to 50 € / $..

hmm..
seems like this is more difficult than i thought..

depending on what someone is willing to give me, i´ll pay up to 50 euro/dollar for hints how to build a suitable converter.

again, i´d be happy about anything, be it plans, hints, parts or a finished converter.

yours

krutzbeuazen

Re: will pay up to 50 ? / $..

If you are interested in red LEDs, I can probably do up to a 100 pieces (just a guess) of 3mm red LED array for you to drop into your 2D mag, but it would probably take me weeks to complete it since I need to order the parts, wait for it to ship to Singapore, solder and so on...

If you are interested in white LEDs, ya gotta have some step up converter of some sort.

I just did a simple calculation. 5 watts divided by 2.5 volts of red LEDs divided by 20ma that they take gives you 100. That's 100 pieces of 5mm LED for 5 watts. So a 2 Badboy circuit could probably get the job done of giving you a super huge flood light with white LEDs

One more way is to use a Badboy circuit to power up 2 1 watt LS in series. Probably a Badboy 400. You can have up to 6 LEDs and 3 Badboys before heat starts becoming an issue. Current draw would be around...4 amps or so. That means battery life would be around 2 hours. Maybe less.

Maybe you would want to state clearly what are your wants. Brightness, run time, type of light, colour of light, usage for the light, etc.

Re: will pay up to 50 ? / $..

This is tacky, but it's easy and might be cheap, too. The MicroPuck converter that a couple of dealers were selling at $10 recently are each able to drive 10-12 leds. Drop a few of those in there, they're really small, and run say 4 or 5 strings of LEDs from 4 or 5 Pucks. Even add a switch to knock out a few, so you can run reduced output longer runtime. Even 6 pucks at 72 LEDs would run about 3.5A at 2.4 volts. Turn off 3 or 4 pucks, and you still have 20-30 leds at full output, and a runtime of 4hours+

Looks like they're still available here at 9.95 each.
http://www.ledsupply.com/02009a.html

These things are easy to use, reasonably rugged, and very small. As well as decent on losses.

Good luck. Hope this helps. I've been trying to think of something better, but not yet.

yours, DRS the crazed.

Re: will pay up to 50 ? / $..

P.S. I'm not up on the Mag's switch capacity. You may find that you'll have to back off on using that many LEDs. May switch to 5MM leds, and fewer of them. You usually get better output as well. Other forum members may have ideas about the mag switch. Just thinking..
drs

Here's where I buy my UV leds. Have had good luck with Chi-wing's products and service, and he includes shipping in the price, and I think that's international shipping..
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=26207&item=2594982267
drs

Re: will pay up to 50 ? / $..

heres an idea. Mod the 2D mag for a 5w w/6aa's or 3C's and a luxII direct drive. Take those NiMH D's and put them to good use in Elektrolumens upcoming tri-star 4D!

Re: will pay up to 50 ? / $..

I've another idea: Get a 3D or 4D mag. It opens up a whole new world of options.

Re: will pay up to 50 ? / $..

Thank you all for your suggestions!

red led´s dont sound that funny, i´d prefer uv or at least white.. i dont have any real use for a led light, so uv would be most fun..

with more and smaller cells i wouldnt really solve the problem, would still need soome kind of regulator capable of 10watts. and i would have to buy akkus for 50$ (current ones too large diameter for 4 to fit) and would waste 50$ for my D cell akkus.. damn..

the micropuck still is the "best" solution i found so far.
"best" with 100$ for 10 pieces, shipping to europe and money transfer costs and so on..

cant be that there is no single converter capable of 10 watts? come on, the bulb in my fridge is more than that ;-)

what about those discrete step-up converters with two transistors and a coil as magnetic energy storage?
(they even had a name, i lost that site with several small versions)
unfortunaly i'm not good enough at electronics to design a bigger version.. again, help please!

krutz

Re: will pay up to 50 ? / $..

Were you thinking of this? Comes from this page, though I'm not sure whose page it is.

Quite a simple design using easily available parts. You should be able to get enough parts to build 10 pieces without breaking the bank. Each one capable of at least 1.25W, though I have a simulation running at 1.8W (about 500mA).

Hmmm... image won't come up if linked directly. Go to the webpage given by my second link, look for "Modified for driving at 350mA with a dimmer". Should be the last link on that page.

Re: will pay up to 50 ? / $..

And BTW, if you are planning to run 10W through the Mag switch, you might want to reconsider. May be better/safer to use the Mag switch to turn on an electronic switch like the IRF520.

Re: will pay up to 50 ? / $..

If you have four of those D cells, why not use a 4D Maglite? The 2D is already so big and heavy that a 4D can't be so much worse...

Re: will pay up to 50 ? / $..

The issue with going with more cells is that you don't need as many converters to do the job since they have more voltage to work with. Also because the current draw will be much lesser through the mag's switch, there will be less losses and hence, longer runtime or brightness depending on how you want it.

Did I mention that it's very taxing for any converter to step up to 10 watts to drive the 5 watts using the voltage supplied by 2 D cells? Not that the current draw is the only issue, but the IC and the inductor must be capable of handing the huge current draw in order to step up to enough voltage to drive the 5 watts. But I see that you've already decided that you might want to go with stacking multiple micro pucks. I worry for the mag switch, you might want to modify it to something more durable.