xet
Active member
Ohhh okay that just gave me an epiphany, maybe, because with a 27.8a driver ----> (240v input x (13.9a from the wall x 13.9 volts)) = (120v output x (27 volt output x 27.8a))
Did I think it right?
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LED FAQ) Building and DIY
- Thread starter Dion
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Did I think it right?
xet
Active member
As far as specs go the cob is 708 pieces of 1w chip. I will go into the wavelengths when I get this thing wired up because it should melt some industry people's heads.
I lost the original specs which said (708 watts @ X volts).
But I bought the chip and the driver from my chip manufacturer at the same time in the same purchase. It took 3 months for the chips to be manufactured.
I started this process 4 years ago.
I lost the original specs which said (708 watts @ X volts).
But I bought the chip and the driver from my chip manufacturer at the same time in the same purchase. It took 3 months for the chips to be manufactured.
I started this process 4 years ago.
From the wall you are only taking 7 A at 120, or 3.5 A if 240V, so the gauge 10 wire there might be like very overkill. I would go with 1 to 1.5 mm2 section, whatever gauge that is, you don't need more. On the DC side, from the driver to the cob, you need gauge 10 or lower (thicker wire), depending on lenght between the two parts, and acceptable voltage drop (loss). There are even calculators online to calculate your loss for various scenarios, with voltage, amperage, wire thickness and lenght taken into account.
xet
Active member
Looking at the charts and reading Three Berries advice +chart about the input being half the output I come up with:
[wall 240] -------10/3(*rated for 15a input)------- [driver 27 volts | 27.8a] -------7/2(*30a output)-------- [cob 708w]
[wall 120] -------7/3(*30a)------- [driver 27 volts | 27.8a] -------7/2(*30a)------- [cob 708w]
[wall 240] -------10/3(*rated for 15a input)------- [driver 27 volts | 27.8a] -------7/2(*30a output)-------- [cob 708w]
[wall 120] -------7/3(*30a)------- [driver 27 volts | 27.8a] -------7/2(*30a)------- [cob 708w]
xet
Active member
I am being confused about the 7 and 3.5 numbers unless you are using examples of how input/output is half. Is the chart being accurate with 15A = 10# and 30a = 7#?
xet
Active member
ooooooooooooo
Then is this seeming to be more correct
[wall 240] -------16/3------- [driver 27 volts | 27.8a] -------12/2-------- [cob 708w]
[wall 120] -------12/3------- [driver 27 volts | 27.8a] -------12/2------- [cob 708w]
each 1 is 708w
each will have it's own driver
Attachments
It's the absolute maximum it can draw on the input size, at lowest mains voltage, and probably only for an instant. You could go one gauge down (one size thicker wires) on the AC side to make sure you have the peace of mind even it the worst instant where the voltage might drop on the mains so higher amperage is drawn, but keep in mind that tables also take those situations into account so a bit of overhead is left.
xet
Active member
[wall 240] -------14/3------- [driver 27 volts | 27.8a] -------12/2-------- [cob 708w]
[wall 120] -------10/3------- [driver 27 volts | 27.8a] -------12/2------- [cob 708w]
Awesome exploziv thank you.
Do I look in the clear here?
xet
Active member
Cool man I really appreciate it. I should document everything here. Probably even better to do that with more eyes looking at what is going on than to have my 1 electrician maybe or maybe not find the time to help
Three Berries
Active member
I'm not really sure of what your wiring is.
120v three wire, hot neutral and ground,
240v three wire, two hot one ground,
240v 4 wire, two hot one ground one neutral
240v one hot, one neutral and a ground.
If in the US I would use 14 ga for 15A ,12ga for 20A and 10 ga for 30A all less than 25 ft.
120v three wire, hot neutral and ground,
240v three wire, two hot one ground,
240v 4 wire, two hot one ground one neutral
240v one hot, one neutral and a ground.
If in the US I would use 14 ga for 15A ,12ga for 20A and 10 ga for 30A all less than 25 ft.
xet
Active member
I am US.
I want to be safe and for it to work and to go <25ft like you describe.
[wall 240] -------does it matter here if 14/4 or 14/3 ------- [driver 27 volts | 27.8a] -------and change 12/2 to 10/2 here?-------- [cob 708w]
[wall 120] -------10/3 is still good here?------- [driver 27 volts | 27.8a] -------and change 12/2 to 10/2 here?------- [cob 708w]
Thank you for the heads up I am very much interesting in not barbecuing myself or equipment
Three Berries
Active member
Some 240V uses a neutral so they can also use it as a 120v. Such as an electric dryer that has one 120v leg for the element and uses the other 120v for the motor.
Otherwise with 2 hot 240v there is no need for a neutral as they are 180 degrees out of phase and cancel each other out. Code may may require it a neutral.
They make special outlets and plugs for the 20A and 30 A stuff too.
Otherwise with 2 hot 240v there is no need for a neutral as they are 180 degrees out of phase and cancel each other out. Code may may require it a neutral.
They make special outlets and plugs for the 20A and 30 A stuff too.
xet
Active member
Luckily I have no code where I am so I can be as dangerously accurate as I want.
Although I dangerously do not understand electricity like I need for this task.
Using my trusty diagram here
[wall 240] -------14/2 ------- [driver 27 volts | 27.8a] -------10/2-------- [cob 708w]
[wall 120] -------10/3------- [driver 27 volts | 27.8a] -------10/2------- [cob 708w]
Is that the cheese for 240 and 120 setups?
And even on 14/2 for my 240 setup there is still outlets/plugs for this?
Thank you Three Berries and Explosiv for chugging my train along here.
Three Berries
Active member
More issues I'm afraid. This trusty watt to amp converter only shows around a 6 amp input load at 120v for 700 watts.
At 24vdc the 700 watts is indeed ~30A.
www.thecalculatorsite.com
So again from what I know I would be using 14 ga for the input and 10 ga for the output.
At 24vdc the 700 watts is indeed ~30A.
Watts to Amps Conversion Calculator
Use our calculator and handy reference charts to convert electrical power (watts) to electrical current (amps)
www.thecalculatorsite.com
So again from what I know I would be using 14 ga for the input and 10 ga for the output.
