100 watts LED powering help.
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If youre trying to do it on the cheap, then I would say, throw that on a CPU heatsink for a high performance processor. There are some with design powers of 120+W. you could get 36v from 3x 12v SLA's if youre trying to do this on the cheap.
30x Ni-Mh cells would be 36v nominal also, over that when fresh off the charger, a series power resistor could take care of that though. 3A is a bit harsh on AA's so you might be looking at an A cell or 4/3A or sub C cells in a pack. If youre handy with soldering, batteryspace sells individual cells with tabs welded on already.
LiFePo4 cells are 3.6v fully charged, 3.2v nominal, so ~11 cells with a series resistor could work.
Lotta choices with batteries, its a matter of what you can shoehorn into a large lantern body, along with the large heatsink this will require. Careful working with packs that big, if you short one out, youre going to have a ton of current in whatever it arc's over.
30x Ni-Mh cells would be 36v nominal also, over that when fresh off the charger, a series power resistor could take care of that though. 3A is a bit harsh on AA's so you might be looking at an A cell or 4/3A or sub C cells in a pack. If youre handy with soldering, batteryspace sells individual cells with tabs welded on already.
LiFePo4 cells are 3.6v fully charged, 3.2v nominal, so ~11 cells with a series resistor could work.
Lotta choices with batteries, its a matter of what you can shoehorn into a large lantern body, along with the large heatsink this will require. Careful working with packs that big, if you short one out, youre going to have a ton of current in whatever it arc's over.
DIWdiver
Flashlight Enthusiast
How long do you want this to run? That will make a big difference in the battery selection and cooling system.
If you want it to run more than a few minutes at a time, with 100W to get rid of, you're going to need either a fan-cooled heatsink as CKOD suggested, or a very large surface area on your heatsink (like 200 square inches). These will dissipate the heat as fast as it is generated, and you can run the light forever, or at least until your batteries run out.
If you only need it to run a few minutes, you can just provide something to soak up the heat while it's running and then get rid of it over a longer perioid of time. Large blocks of metal (especially aluminum and copper) work well. Water is great, but a little inconvenient.
If you post some more info about what you want it to do, you'll get better suggestions back.
If you want it to run more than a few minutes at a time, with 100W to get rid of, you're going to need either a fan-cooled heatsink as CKOD suggested, or a very large surface area on your heatsink (like 200 square inches). These will dissipate the heat as fast as it is generated, and you can run the light forever, or at least until your batteries run out.
If you only need it to run a few minutes, you can just provide something to soak up the heat while it's running and then get rid of it over a longer perioid of time. Large blocks of metal (especially aluminum and copper) work well. Water is great, but a little inconvenient.
If you post some more info about what you want it to do, you'll get better suggestions back.
deadrx7conv
Enlightened
I run a 50w LED off a group 24 deep cycle marine battery. Needless to say, that battery was a little too small and a pair of GC2 Energizer golf-cart batteries works fine.
Do you want 5 minutes of light or 12hrs?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=260652844090
You might be able to get away with a voltage booster. This way, you can use a 12v SLA battery from a computer UPS. And, with the knob, you can dial in the voltage for output control.
Battery options like a 6,9, or 12-cell laptop packs with 18650's should give you decent run time.
Mount the LED to a fancy CPU heatsink/fan combo. Mount that to a handle-equipped ammo can. Fill the can with batteries and there you go....mad chug along lighting!
http://armysurplus1.net/catalog/images/AmmoCan30Cal.jpg
And, don't forget that you're not forced to run the LED at 100w/36v.
It'll probably start to light up bright from 10+ watts. And, I'd bet it'll eat about ~35w and be plenty bright from a single 12v auto battery.
Do you want 5 minutes of light or 12hrs?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=260652844090
You might be able to get away with a voltage booster. This way, you can use a 12v SLA battery from a computer UPS. And, with the knob, you can dial in the voltage for output control.
Battery options like a 6,9, or 12-cell laptop packs with 18650's should give you decent run time.
Mount the LED to a fancy CPU heatsink/fan combo. Mount that to a handle-equipped ammo can. Fill the can with batteries and there you go....mad chug along lighting!
http://armysurplus1.net/catalog/images/AmmoCan30Cal.jpg
And, don't forget that you're not forced to run the LED at 100w/36v.
It'll probably start to light up bright from 10+ watts. And, I'd bet it'll eat about ~35w and be plenty bright from a single 12v auto battery.
alpg88
Flashlight Enthusiast
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hooking battery directly might fry the led, since nothing limits current, driver would be the best thing, thou i can't tell you where to get one, i have not seen 36v 3A dc drivers.
or you need to add some volts, and use resistor, build your pack few volts higher, and use power resistor,
for example 37,2v (31 1,2v cells)
you would need to dissipate 1,2v you need 3 amps, so resistor would need to be 0.4 ohms 3,6w,
exact specks are hard to find, if possible at all, but 0.5ohm 5w resistors are not hard to find, it will work fine in your set up.
or you need to add some volts, and use resistor, build your pack few volts higher, and use power resistor,
for example 37,2v (31 1,2v cells)
you would need to dissipate 1,2v you need 3 amps, so resistor would need to be 0.4 ohms 3,6w,
exact specks are hard to find, if possible at all, but 0.5ohm 5w resistors are not hard to find, it will work fine in your set up.
deadrx7conv
Enlightened
Limiting voltage is acceptable. Can't fry a 36v LED using 12v.
alpg88
Flashlight Enthusiast
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will it even light up at 12v???? have you tried???
I've tried to connect it to a 12v battery and nothing happens. It's really hard powering up this monster, for 36v 3SLA battery will be tonne heavy for a portable lamp. Tried to search for drivers all around for 36v but with no luck. The only driver I have is currently a 230V to 36V 3Amp driver. Maybe the only way I can connect to this LED is to use a 12V Inverter. Btw, if I have a 3AH SLA battery and I connect it to the inverter, if the output of the driver is 36V, does it means that the efficiency of the battery became 1AH instead of 3?
Thanks for all the help given.
Thanks for all the help given.
ask this guy:
http://www.youtube.com/watch?v=wX3PsoZHTL4
http://www.youtube.com/watch?v=wX3PsoZHTL4
alpg88
Flashlight Enthusiast
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- Messages
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not exactly but close, factor in invetrter\driver loses, you might end up with a lot less.
Actually, LiPo cells can be very inexpensive. I use LiPo cells for radio-controlled airplanes and trucks, and I buy all mine from hobbycity.com. Their Zippy brand cells in particular are very good, even compared to much more expensive brands. I regularly drain my packs at 20-30 amps, so they're not going to complain about a 3-amp draw.
Since soldering LiPo cells is generally not encouraged for people who don't already have quite a bit of experience with safe handling of the batteries, I'd suggest getting a few packs and wiring up a harness to plug them into your LED driver in series. Three of these in series would give you 45-60 minutes of runtime and only weight about 1.5 lb.
I personally use this charger, which would also work well for your project (needs a 12v, 5a power supply).
You'd also need a low-voltage alarm, something like this, on at least one of the packs, because LiPo cells are very rarely protected, and it'll be hard to tell when your light is dying, since it's so bright. Just like protected Li-Ions, though, the alarm only goes off when the voltage is dangerously low, so ideally you'll always recharge well before it goes off.
Hope that helps!
(Also, I'm still kinda new here and don't know exactly what the tolerance level is for a bunch of links promoting something. I hope this post is within the rules, but if not let me know and I'll tone it down)
deadrx7conv
Enlightened
Yes, I've tried on various LEDs. But, I don't have that DX one.
If 12v doesn't work. Use 18v, 20v, 24v, or 30v. You can connect batteries in series until you get the voltage you want to test at. The later(higher voltage) it starts up, the less likely its grossly over driven cheap garbage with a short life and quick fade. I would not go over 33v without power meter. You can use 2 DMM's to watch voltage and current at the same time (do the power math in your head).
And, don't forget that 3x 12v batteries fully charged can be between 39v and 45v far exceeding the LED.
10x 18650 is a reasonable small sized battery pack.
I saw some Li-Poly pack on http://www.dealextreme.com/details.dx/sku.41208 which I think it may be a good buy. Purchasing 3 of it and connecting it in series to power up the led. The size and the weight of the battery will be uber light. I suppose it is safe to connect 3 Li-Poly in series during discharging/load right?
I suppose 10x 18650 will only give me 2.8AH max which will not light up the light for more than an hour.
Another thing I wasn't sure of is those LED drivers. Can I connect more than 1 drivers while still using the modes of the drivers?
I suppose 10x 18650 will only give me 2.8AH max which will not light up the light for more than an hour.
Another thing I wasn't sure of is those LED drivers. Can I connect more than 1 drivers while still using the modes of the drivers?
MikeAusC
Enlightened
A CPU Heatsink using Heatpipes and rated for a 150 watt processor will give great cooling without massive weight.
spencer
Enlightened
Look at the HyperBoost from TaskLED for a driver.
MikeAusC
Enlightened
You'll need two of them to supply 2.8 amps.
