LED build design phase questions/suggestions

Growroom Design
#21

@anon32470837 is absolutely spot on. @Daytripr69 you’re definitely starting to grasp it now. Series wiring spreads your voltage so you can use a higher load driver. Parallel keeps voltage low. nd if you have a failing strip the rest should stay lit.

Look at the max load of the drivers you intend to use. My plan is to wire 8 x 1120mm strips in series to an xlg240L-AB

The XLG240-L-AB has a Max output voltage of 342v and drives at 700ma.
We know the strips are driven at 39v

So let’s do some maths
342÷39 = 8.76

It would be possible to round it up to 9 strips but 8 works for the spacing on my intended build.

Now we do 8x39=312v

Because we’re working 700ma we then need to do

312x0.7=218.4

218.4w of actual draw from the wall.

Now let’s work on efficiency. We know the drivers are 89% typ efficiency.

So we would take 218.4x0.89=194.37w (usable light)

Say we were using the 1120 3500k strips at 175lm/w

We would do 194.37x175=34,014 lumens.

@anon32470837 was spot on when he spoke of the inverse square law. You can get these practically on top of your plants. You can’t do that with HPS so stuff does kinda balance itself out quite niceky

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#22

The test voltage on the strips i was looking at was 700ma but max wss 1.4 Which one would I go with to calculate my wattage? I’m assuming 1A would suffice but unsure. Only want to buy parts one time lol

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#23

Sorry, I missed this somehow.

The 1.4 amps is probably the max amps, and the 700 is the design or working amps. For long life, and max efficiency, you want to run close to that 700ma number, but they can be pushed to 1.4 amps if you dont mind running less efficiently (more energy wasted as heat for each watt of input) and shortening their life to some degree. There should be another spec for voltage and/or maybe a graph of voltage vrs current. The relationship is not linear, and generally there is a very narrow voltage band, but that depends on the exact diodes used in the strip.

Edit: sorry - that answer just made things seem more complicated and probably didnt help you decide anything :nerd:

I think I said this somewhere, but you dont need to worry about current that much. The driver will handle the current.

To keep it simple you need to look at total voltage in series, and total current in parallel.

I would use the 1.4 amp number. Then multiply that 1.4 by the total number of strips in parallel. That will be the max amps the driver will need to supply - if you over drive them. I would go maybe 5%-10% higher to be safe, but Meanwell drivers are bullet proof, so just getting close is fine.

Then add up all the voltages of the strips in series and that gives you the max voltage for the driver.

You might want to do a simple drawing of how you plan to wire the fixture and post a link to the specs or a pic of the spec sheet. Then we can double check it for you.

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#24

Larry is spot on. Current Max is 1.4 but “optimum” is 700ma. The meanwell. You wanna be looking at 700ma drivers (the XLG-----L-AB are 700ma. You have to start looking towards performance curves of the diodes on the data sheets to actually know if its worthwhile overdriving. In the case of EB2s not really although if you do still wanna you can overdrive the XLG drivers slightly using a potentiometer.

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