Silly Question

[LeanMcsheen]

I have built myself a 8x cxa3070 grow light similar to goud's battlestar ganjatica, each running on a MW lpc60-1400. I have a kill-a-watt style reader and it's telling me that at the plug i'm pulling 484+/-watts, 239v and 3.09+/-a... (just LEDs, no fans) surely that isn't right? I thought it would pull 11.2a because each driver is at 1.4a? I'm in the UK if that makes any difference, surely not? Is my kill-a-watt type reader wrong? or did i just misunderstand the whole amp side of things?

 

[AquariusPanta]

Supra just experienced a faulty killameter and shared his solution in a recent thread... so it is possible that yours is faulty.

 

[medicinehuman]

I have built myself a 8x cxa3070 grow light similar to goud's battlestar ganjatica, each running on a MW lpc60-1400. I have a kill-a-watt style reader and it's telling me that at the plug i'm pulling 484+/-watts, 239v and 3.09+/-a... (just LEDs, no fans) surely that isn't right? I thought it would pull 11.2a because each driver is at 1.4a? I'm in the UK if that makes any difference, surely not? Is my kill-a-watt type reader wrong? or did i just misunderstand the whole amp side of things?

From what I understand is that you should not have more than 60w draw from each driver, if you have 8 than that = 480w. Driven @ 1.4A is 52w each x 8=416w Amps will be x also. I think this is correct. My watt meter just messed up, I was way over on everything.

 

[Greengenes707]

There is input and output data for each driver. The input is what effects your kilowatt/electric meter. and what you need to look at when making sure you don't overload a breaker or whatnot.
Those drivers are not PFC corrected...and PF is normally lower on high voltage like 240 or 277...so that probably explains the higher amps. But your 484 wattage is correct +/- a few. 416w diapation plus driver efficiency of 85%...so 416*1.15=~478w

The 1.4a is the output in DC...not exactly relevant to the input the driver is talking from the wall for what we are talking about.

 

[JavaCo]

Amps seem to be wrong. Data sheet has the lpc-60-1400 as a 58.8 watt driver including efficiency . Watts seem to be close to being right. They are 58.8 watt drivers including the efficiency. so 58.8 x 8 = 470.4 watts total. So that is pretty close. Amps should be lower though. 484 watts divided by voltage 239 volts gives you amps. So 484 / 239 = 2.025 amps is what ohms law says you should be pulling if the watts and voltage reading is correct that is. Amps are not universal across voltages. So 1 amp at 36 volts is much different then 1 amp at 230 volts. Power or watts is Universal across voltages though 1 amp 36 volts is 36 watts 1 amp 230 volts is 230 watts. There is alot more power/watts in that 1 amp 230 volts. So when the driver converts 230 volts down to 38 volts it doesnt need 1.4 amps to make 38 volts 1.4 amps. Ohms law will tell you what current it will draw @ 230 volts. 58.8 watts divided by 230 volts = 0.255 amps per a lpc 60 1400 driver.

 

[alesh]

I have built myself a 8x cxa3070 grow light similar to goud's battlestar ganjatica, each running on a MW lpc60-1400. I have a kill-a-watt style reader and it's telling me that at the plug i'm pulling 484+/-watts, 239v and 3.09+/-a... (just LEDs, no fans) surely that isn't right? I thought it would pull 11.2a because each driver is at 1.4a? I'm in the UK if that makes any difference, surely not? Is my kill-a-watt type reader wrong? or did i just misunderstand the whole amp side of things?

It's actually an expected result. 484W sounds about right. 3.09A at 239V sounds like your drivers are not power factor corrected and thus pulling slightly more.
e: @JavaCo Things are not as simple as power = voltage * current when dealing with AC.

 

[LeanMcsheen]

Ah, my bad, i wasn't looking at the input numbers. Thanks everyone, told you it was a silly question lol

 

[JavaCo]

It's actually an expected result. 484W sounds about right. 3.09A at 239V sounds like your drivers are not power factor corrected and thus pulling slightly more.
e: @JavaCo Things are not as simple as power = voltage * current when dealing with AC.

I wasn't saying the watts were wrong 484 watts is well within the tolerance of the driver . Kill a watt meters are power factor corrected It gives you the true wattage your device uses not wastes in reactive and harmonic amps. They will also tell you the power factor. I was saying the amps were off. Cause 239 volts x 3.09 amps is 738 watts. If the 3.09 amps is right a combination of good amps and harmonic amps wont be any reactive amps cause there is no motors involved. Then these drivers have a really shitty power factor of .66. Didnt think they were that bad makes the HLG series look that much better. Not that most electric utility companies charge for harmonic and reactive amps for home users, but it Seems to be changing, 5 or years ago there was only a one Electric company i knew about that charged for reactive and harmonic amps. But searching to today i saw another one that gives a penalty for having a power factor below .90.

 

[alesh]

I wasn't saying the watts were wrong 484 watts is well within the tolerance of the driver . Kill a watt meters are power factor corrected It gives you the true wattage your device uses not wastes in reactive and harmonic amps. They will also tell you the power factor. I was saying the amps were off. Cause 239 volts x 3.09 amps is 738 watts. If the 3.09 amps is right a combination of good amps and harmonic amps wont be any reactive amps cause there is no motors involved. Then these drivers have a really shitty power factor of .66. Didnt think they were that bad makes the HLG series look that much better. Not that most electric utility companies charge for harmonic and reactive amps for home users, but it Seems to be changing, 5 or years ago there was only a one Electric company i knew about that charged for reactive and harmonic amps. But searching to today i saw another one that gives a penalty for having a power factor below .90.

To be a smartass, I wasn't saying that you were saying that power (watts) had been wrong.
Apparent power would be in VA.