LED Lighting Wiring Question

Would it be okay to take an HLG 260 Watt Quantum Board LED Kit V2 Rspec × 2 and wire it such that only one of the LED boards is receiving current?

I have a sole, young plant in veg and it just doesn’t need both boards running. I’d like to conserve some wattage.


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@dbrn32 Here is a good question for ya.

Personally I don’t think it would work. You would probably need a better driver for it to work aka one that can handle the lights on the same driver.

You can always run just one board with the two QB’s and just crank it to the max power setting.

I may have confused with the x2 (I copied from my invoice.) The times 2, meaning that there are 2 PCBs on the assembly. To clarify, I am talking about using the ballast to drive only 1 of the 2 PCBs on the assembly.

If you’re driver is rated for 2 boards and you run only one board you will be fine

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The ones I look up say they are wired in series so you cannot disconnect one board.
You need parallel wiring to be able to do what you want.
In the Series circuit removing a bulb breaks the entire circuit and bypassing it by removing it from the circuit applys more voltage to the rest of the bulbs and will burn them up.
In the Parallel circuit the same voltage is applied to each bulb and removing one has no effect on the others.


I’m talking about not wiring the second board at all. No series, no parallel - wired as if the second board isn’t there.

But removing the board will apply more voltage to the remaining one because its already wired in series. Its designed to split the voltage between the two boards. If you bypass one you will burn up the one other.
If it was wired in parallel to begin with then you could disconnect one.

Using the ballast to drive only one board and burning that board is what I was worried about.

Im basing this on the little bit of info I see on their website.
If the driver has some sort of voltage regulation then maybe. Which model power supply is it exactly?

The model on the ballast says HLG-240H-C2100A.

The single board model (ballast labeling) on the HLG website is HLG-120H-54A.

Voltage range on that one is 59 to 119 volts, and a single board is rated at 54 volts…
Its not possible with that driver…Unless you put a dummy load in line and then you defeat the purpose of saving power.

Appreciate your input, @Spiney_norman.

The single board is $200, so I’m not really saving anything by ordering a single board either.

Using HLG-120H-54A as a driver you could power one board.
We are talking about a small savings tho…
At full power 130 watts is about 3 kwh per day and at 15 cents a kwh that is 45 cents a day.
If you spend 50 dollars on a driver you will have to run it about 200 days 24/7 to save 50 dollars.
And you will have to rewire the whole thing back with the original power supply when you want two boards.
On a 12/12 schedule it takes over a year, 400 days to break even.

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On paper it doesn’t work because the forward voltage of 1 board doesn’t meet the minimum forward voltage requirement of that driver. However, I have seen them work outside of their listed spec. So you could try if you want.

There is no concern for over voltage or over current with that driver and one board. Its constant current driver, and board is rated for all the current driver will produce. Although, I am wondering why you would go through the hassle of rewiring for such short period of time when you can just dim it?


Rewiring would just be a matter of disconnecting the second board and running the neg on the one board back to the ballast, so not much to it.

I may try it if it isn’t going to damange anything. Damage is what I was worried about.

I thought of it and was more curious than anything. Just wondering it it is feasible.

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Not on paper, but I’m guessing 50/50 chance it will. Only risk of damage that I see is if you break connector in process of wiring.

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Just use a couple 23w cfls or smaller household LEDs until they are a little bigger then use your quantum board dimmed down

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Im with Dbrn32, just dim it all the way down. Or, Drop more seeds!!!

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