led zep - originally i had the idea of halo work lights and a generator
but the cost and weight put me off - and all the messing with petrol etc
so then i made this tripod but for a year it had 2 x 50w halogen globes
obviously not as bright as the work lights but cost 1/4 of the price of a generator but the battery started dimming at 40mins runtime and was dead after 1hour - not good for skating or for the SLA battery
so this winter i did the cree's - now it lasts twice as long and is just as bright
and you can carry all this in a backpack
just need to work on a bit of protection for the front
not sure about the heatsink i just got them off an IT guy i know
but i do have another one
so can anyone help me figure out what im driving these cree's at??
I wouldn't have paralleled the LEDs though, as the one with lower Vf will suck more current and eventually burns before the others, and then the others would burn. I have a couple of cheap torches with parallel LED, they reliably and systematically burned.
Please correct me if I'm wrong about parallel / unbalanced load / burning; as I am not certain about the theory behind resistors
I prefer 3 buckpucks 1000mA for 3 Cree each; they're cheap, potted, and efficient. If you want to spend extra $ you can have the ones with external potentiometer; as you can overdrive them up to 1200mA.
I made a fixed lighting with BuckPuck with ext. pot. and it scares my wife; she said that she couldn't accept the fact that a tin chocolate box can emit light; she feared explosion
Ive thought about doing that (the local police took issue with us parking out cars on the skatepark for night time bmxing). so its good to see it working might motivate me to do something (got other (mostly unrelated) projects to do first though).
Ive not experimented much with high power LEDs yet but i think you you wont get the problems mentioned of parallel LEDs because you (correctly) havent used one resistor for parallel loads.
Amazing build , I am definitely building one of these. I have decided to run 4 of the tri-LED Rebel stars, 2 in parallel for each 1000mA Buckpuck. Because of the 2v drop across the buckpucks each LED will be receiving 10v @ 500mA, which I figure is close enough to the recommended 9.45v. I am going to use a large heatsink, although not quiet as bis as yours, but I was wondering how you attached the heat sink to the tripod mount. I was thinking of using epoxy, but it doesn't look like there is a great deal of surface area on the tripod to work with.
Input 12v 2A
Output 1,300 lumens
so id be interested in knowing the current to each cree (at the start and end of 1hour)
let me know what you think of the light (and the answer)
It's a pity no one ever answered that question. The light is great, but to give you an answer we also need to know what the operating voltage of each triple LED string is. Something around 10.5-11V probably.
No, a torch does not always mean flames.
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Dude, this is almost exactly what I've been planning! I got a couple aluminum blocks in earlier today (technically yesterday), and I drilled and tapped them for tripod mounting. I'll be using 11 Crees in series with a 1-ohm resistor and three 12V 10Ah SLAs (also used in myHMM) for the larger one, and four Crees driven by two KD "Kennan" drivers for the smaller one. I'll be finning the blocks and painting them black for emissivity.