Introducing CobKits.com - specializing in DIY and Citizen COBs

CobKits

CobKits

Well-Known Member
sorry i havent been around guys, jsut getting over a stomach bug that had me out for a few days. Focusing on getting orders out

**heads up im travelling from 1/10-1/15 so if you need something get the order in today (tues) if you want it to ship before i leave. next shipping day after that is monday 1/15**
 
CobKits

CobKits

Well-Known Member
KonopCh said:
Based on Citi gen 5 calculator. Heatsink run under 30°C. 6x1212 COBs = 37W * 6 = 222W.
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thats not going to get you very close as you dont know case temp or junction temp nor actual current. jsut measure voltage and current and you'll know right away
 
KonopCh

KonopCh

Well-Known Member
nxsov180db said:
It's a 240 watt driver, It'll run more than that when turned all the way up they always do. I have 13x 320's and some of them run over 380 watts..
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But I didn't take full driver, there's place for another 25-30V I think. I think it's quite a bit number --> 60W difference, as driver should be 93% efficient.
 
KonopCh

KonopCh

Well-Known Member
nxsov180db said:
I believe the driver will run at the full wattage even if you are not using the maximum voltage output. I have an unknown brand driver I re-purposed that used to drive a single COB at 30 volts and drew around 210 watts, I now have it driving led strips at its max output of 46.5 volts and it still has the same watt pull.
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That was I thinking, but guy on this page said it's not possible. See little above.
 
CobKits

CobKits

Well-Known Member
changed my travel plans, ill be around today for orders. leaving tomorrow (thurs). so thurs-sun orders will ship monday.
 
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pop22

pop22

Well-Known Member
The efficiency is the difference between draw at the wall and the actual power provided to the cobs. As was stated, you have to measure the voltage and current drawn by the cobs with a meter to determine these numbers. My QB light draws 363 watts at the wall on a 320H-C2800B. The actual draw of the boards total is 340 watts so right about 94% efficiency.

It will NOT draw 320 watts if you don't put that load on it, its a CC + CV driver, it only provides what the cobs want, ie, it won't try to sen 320 watts into a pair of cobs, it will send, say 36V @ the rated current, mine would send 2.8 amps to each 36V cob for 100.8 watts per cob, 201.6 for the pair. This is how constant current/constant voltage drivers work

KonopCh said:
216V * 1.28A = 276W..
But... 280W-276W = 4W... That is not 7% from 93% efficient driver.

Also another question... If I add another light on that driver (shows 280W MAX) to fully load it with V... it will be 280W or even more? Or better ask, driver shows 280W even if it's 90% full or 70% full?
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pop22

pop22

Well-Known Member
No, the cob determines the wattage consumed. Volts x Amps = watts. Undimmed, the C2800b I mentioned can provide 2.8 amps to each cob in series until the max voltage available is used by X number of cobs. so wattage would be based on a cob drawing 36V,
36x2.8= 100.8 watts. so this driver would max at three cobs, based on both amperage and voltage, as the driver voltage range is 57-114 volts. So three cobs max.
The drivers "wattage" rating is based on arbitrary best numbers. It means nothing other than that this is the rated max that Meanwell will offer warranty support to..

nxsov180db said:
It'll provide whatever the COB wants voltage wise as long as it's in the voltage range of the driver yes, but the only thing that determines the wattage is the driver not the COB. The driver has no idea how much wattage your COBs are..
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pop22

pop22

Well-Known Member
Ahh, sorry, i missed it was a no name. Not telling what it will do then..lol

nxsov180db said:
I don't believe my unknown brand drivers do either after a little more testing. The driver I tested after disconnecting a 30 volt COB and wiring up to some 48 volt leds (driver maxes out at 46.5 volts) is pulling 205 watts at the wall but the other 3 unknown brand drivers are actually between 250-270 watts so the one driver that is only pulling 205 watts must have been a weak driver from the beginning. Before I disassembled these single COB/driver lights I measured a couple of them to see what the watt draw was as they claim 210 watts and the 2 I tested were right around that number but I must have had a weak COB/driver combo that probably only pulled around 160 watts initially..
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CobKits

CobKits

Well-Known Member
nxsov180db said:
We're both kind of right. I guess I should have been more clear. The driver will put out however many watts it wants to at a given voltage. A 36v COB could only be rated for 100 watts but if it is hooked up to a driver that puts out 200 watts at 36 volts it will receive all of those 200 watts.
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COBs cant operate (far) off of their voltage/current curves, so what you say is possible but not likely with a properly selected driver
 
CobKits

CobKits

Well-Known Member
which driver specifically?

different results for A or B drivers

B driver = all the driver's current at 36V = cob will take 1800 mA
A driver = all the driver's current at 40V = cob will burn out immediately
 
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CobKits

CobKits

Well-Known Member
as an aside i just got my mind blown by my favorite band's lightshow.

the new lights are like a giant cob with like 30 elements, each one is basically a spotlight pattern, is addressable and probably has RGB in each cell to make an infinite number of colors and patterns. ill upload a video when i see one and am curious to find out what fixtures they are
 
ANC

ANC

Well-Known Member
I just want to add something one needs to keep in mind. When driven at 100% load, drivers are most efficient. As we back down the power, driver efficiency falls by a few percent while LED efficiency goes up.

When I decided between 4 and 3 strips for my lights I worked out efficiency at full and veg power, cost of the unit and how much money it would cost to run for a year.
Looked at both options and I would take about a year on power alone to make up the cost of adding an extra strip. As I still need to cover more space with more light, at this stage the less efficient option is still the most efficient at getting the grow space completed.
 
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