DiY LED - Cree CXA3070
- Thread starter SupraSPL
- Start date
alesh
Well-Known Member
Basically, you're only limited by upper voltage limit of your driver and/or how big losses you can tolerate.
The voltage drop and associated losses depend on 1) current used, 2) thickness of the used wire, 3) length of the used wire.
Some examples...let's say you're running single CXA3070 at 1.4A, got 18AWG wire. At 1.4A you need about 37V (let's assume exactly).
1m (3 feet) distance driver-COB: ~0.12V voltage drop, ~0.168W losses
5m (15 feet): ~0.6V drop, ~0.84W losses
10m (30 feet): ~1.2V drop, ~1.68W losses
For a single COB at 10m distance, you'd need about 38.2V instead of 37V and you'd lose about 1.7W, which is about 3.1%.
You can check any combination yourself in this calculator. (the wire goes to COB and back, use distance x2)
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Al Yamoni
Well-Known Member
Hey all, can anybody identify the individual wires of the power cord in this pic? Can I test via multimeter? I really need to get better at using this thing..
This is nearly the last thing to wire before inspection inspection test fire!
Please and thank my friends.
This is nearly the last thing to wire before inspection inspection test fire!
Please and thank my friends.
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alesh
Well-Known Member
This would be my guess. edit: Guess only, you should check with a multimeter.
You can test it easily with a multimeter. Use continuity (beep) mode. Then attach one probe to any pin on the cord and with the other check all the wires on the other end until you hear a beep sound.
Here's a nice tutorial.
a Youtube vid
You can test it easily with a multimeter. Use continuity (beep) mode. Then attach one probe to any pin on the cord and with the other check all the wires on the other end until you hear a beep sound.
Here's a nice tutorial.
a Youtube vid
Al Yamoni
Well-Known Member
Thanks! That was just what I needed and how I needed it! You're awesome.
JavaCo
Well-Known Member
You can go pretty long with them. The longer the run , the thicker the wire gauge you should use. Can't really be anymore helpful then that with out more info.
Al Yamoni
Well-Known Member
Just popped in to say that your diagram was 100% correcto!
Edit: Also, what to do with the little metal wire that is poking off to the side??
good light
Active Member
Just signed up after reading about the good work you all are doing the last few days. I am beginning to get a feel for it.
Hope you can help me with concept of Dissipated Power. Is that the non light power going to the heat sink or total power used?
And when you say, for example, you have 25 watts per sq ft are you referring to total power to the leds or just power that actually becomes light?
Thank you
Hope you can help me with concept of Dissipated Power. Is that the non light power going to the heat sink or total power used?
And when you say, for example, you have 25 watts per sq ft are you referring to total power to the leds or just power that actually becomes light?
Thank you
good light
Active Member
SupraSPL
Well-Known Member
Yes 16 gauge would do the trick. You can get it with nice thick jackets from extension cords at Home Depot ~$0.25/ft or even cheaper from the lamp cord style extension cords.
@good light dissipation watts are referring to the light and heat generated inside the LED. When we say 30W/ft² that is referring to dissipation power. It would be more clear to refer to actual light power (PAR W) so if you know you approx LED efficiency you can estimate that. I use about 13.5PAR W/ft² which I think is a good compromise between nug size and efficiency.
@good light dissipation watts are referring to the light and heat generated inside the LED. When we say 30W/ft² that is referring to dissipation power. It would be more clear to refer to actual light power (PAR W) so if you know you approx LED efficiency you can estimate that. I use about 13.5PAR W/ft² which I think is a good compromise between nug size and efficiency.
good light
Active Member
OK. I think I got it. So at 50% efficiency to get 13.5 PAR W/ft you would be at 27 dissipated watts per COB.
Thank you for all your work that you are sharing. I am most appreciative, particularly, with supply power costs here doubling in a month or so.
mc130p
Well-Known Member
So, am I reading the picture wrong or does it say 1.35A +/- 5%? Because then the 1.25A is actually almost within tolerance. I'd say the driver is working as advertised.
The driver on his store was not the same one I got I ordered 1.4A driver that was power factor corrected. He sent me a cheaper one then I ordered and then told me the sticker was wrong and that it was in fact 1450mA(which was bullshit). This equates to wattage/ounces/efficiency lost in my grow. We are just pointing out how I didn't get what I paid for. I have more drivers coming from a differ seller now. And the original seller is now not answering my emails after I sent him a picture of what his driver ran at. Therfore I have to settle the dispute with eBay.
alesh
Well-Known Member
It's just for mechanical protection, you can cut it off.
happy75
Well-Known Member
Well...last night I finally finished my build. Last days I was reading about light and the maximum of pars, lumens or watts that you can use per square meter or ft. My last grow was fine, but not very well if you put it next to the watts I used. I know now that there is a max you can use, in our country they say that the max is 500 hps watt per square meter. Supra also stated something like this.
First I wanted to use 55 cobs (i wrote that on 16-12 in this thread) but building was just fun and I used every part, cob, alinpine cooler I had and I finished last night or very early this morning, resulting in 14 strings of 1 meter and containing 5 cobs per string (total of 70 cobs). One string is 1 meter and is just a very light aluminium frame which is put together with popnails. The Alpine coolers are just hanging on the frames. Very simple and easy. On the Alpine coolers I use Ideal chip holders`, which did spare me much soldering.
I use 14 HLG-185H-C1050A (7 per boards) and I will dimm them to 0.95 amps to get the right amount of light on the canopy (only 5 square meters). Total wattage would be something like 1700 watts. On max it generates almost 2800 watts, that is too much for 5 square meters but it gives me the opportunity to extent the growroom in the future. I still need to build two fandriver boards. I use one driver per string, the Alpines are driven by a cheapo powersupply from china (12V - 0.8 amps), it is adjustable with a screwdriver, to 9V. To drive the fans of the mechantronix heatsinks, I use a driver of meanwell 7.5 volts - 2 amps. Both fans are now very quiet.
I need to figure out how to adjust each one of the strings becease I cannot reach the end of the growing room anymore. Thats a job for this weekend.
I am no electrician and never used that much electrical equipment, but it is very much fun to learn how to use equipment and figure stuff out. Also, it cost me a small fortune to build this, but I am sad that this build is finished. Almost sad.
First I wanted to use 55 cobs (i wrote that on 16-12 in this thread) but building was just fun and I used every part, cob, alinpine cooler I had and I finished last night or very early this morning, resulting in 14 strings of 1 meter and containing 5 cobs per string (total of 70 cobs). One string is 1 meter and is just a very light aluminium frame which is put together with popnails. The Alpine coolers are just hanging on the frames. Very simple and easy. On the Alpine coolers I use Ideal chip holders`, which did spare me much soldering.
I use 14 HLG-185H-C1050A (7 per boards) and I will dimm them to 0.95 amps to get the right amount of light on the canopy (only 5 square meters). Total wattage would be something like 1700 watts. On max it generates almost 2800 watts, that is too much for 5 square meters but it gives me the opportunity to extent the growroom in the future. I still need to build two fandriver boards. I use one driver per string, the Alpines are driven by a cheapo powersupply from china (12V - 0.8 amps), it is adjustable with a screwdriver, to 9V. To drive the fans of the mechantronix heatsinks, I use a driver of meanwell 7.5 volts - 2 amps. Both fans are now very quiet.
I need to figure out how to adjust each one of the strings becease I cannot reach the end of the growing room anymore. Thats a job for this weekend.
I am no electrician and never used that much electrical equipment, but it is very much fun to learn how to use equipment and figure stuff out. Also, it cost me a small fortune to build this, but I am sad that this build is finished. Almost sad.
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happy75
Well-Known Member
70 cobs now, its a bit big.
happy75
Well-Known Member
There are some calculators on the internet that you can use to calculate the wire you need and the maximum length.