Need help with driver selection plz

HardLuck71

HardLuck71

Well-Known Member
Hi all, so I’m building some 2’ x 4’ fixtures using J series (Cree) strips from Cutter at 8 strips per and looking to run at about 750ma (roughly 37w per) but I know nothing about drivers so hoping some of you more experienced n this area can help me. I heard it’s best to run in series with constant current but not 100%. I greatly appreciate any help, thanks!
 
I think you would get faster help if this was in the LED section....those techie dudes dont leave that section too much lol

I really wish i could help man, but i fear id just be guessing lol
 
What is the combined wattage of your array, and what voltage do your strips run at? It’s pretty simple. If you’ve got, say, two 60 watt strips that run at 48 volts, you’ll want a 120 watt driver with a constant current range where that 48 sits right in the middle. For my example build of two 60 watt, 48 volt bars, you would want an HLG-120h-54a. 54 is its max voltage and 48 is in a nice spot in the range. So, tell me the voltage and max wattage of each strip, I’ll tell you which driver will work. A lot of people were kind of over complicated with their answers when I was trying to learn all this so I’m trying to relay it in a simpler way. You already said you want 8 strips per light, so all I need to know is the voltage and max wattage of each individual strip. If you don’t know that off hand you can post a link to the data sheet and I’ll explain how to decipher it.

One other thing, is that people may tell you to wire these strips up in series, which I recommend against. Each strip is already a series circuit and multiple series circuits should be wired in parallel. Series wiring is more for single high output cobs. Parallel is a little more work but that way if one strip goes out it won’t fuck your whole light. Some strips and boards can only be wired in parallel and if you try to wire them in series they won’t light up. One last thing. I prefer the DIY forum to the LED forum. Hands down. I like the DIY forum because if you’re half assing something they’ll let you know, and help you find the resolve to do something right, even if cutting a corner seems like a good idea at the time.
 
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An LED strip does not have a specific wattage. They will have a maximum current capability, and a required voltage value, but the wattage is not known until the current level is established. Watts are a unit of consumption, not output.
 
Chip Green said:
An LED strip does not have a specific wattage. They will have a maximum current capability, and a required voltage value, but the wattage is not known until the current level is established. Watts are a unit of consumption, not output.
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I understand that, not too sure what u mean. I was just trying to add em up to see about what total wattage I would be at. This is all new to me so I’m just trying to understand bud
 
Wattage is determined by the formula P=IV. Current times voltage. Whenever I mention watts, and I’m sorry for not being more specific, I’m speaking in terms of maximum wattage which is just my easy way of figuring out what “size” driver to get. What is much more important is the constant current range of the driver. I figure out the wattage of the driver by calculating the combined power draw of everything in the array. The constant current range is what needs to match between the strips and driver.
 
So if I were you, I would really want that higher constant current range. Especially the more strips you have. What I really think, after going through the datasheet again, is that you should do 8 strips. At full power they’ll use 200 watts. I think an 8 strip build, and this is when I would break my rule to always wire in parallel. I would do two daisy chains of 4 strips, and parallel them together. That way you still have some redundancy if a strip fails but you won’t have a god-awful octopus of wires everywhere. Get an HLG-240h-54a - the same driver that I have running my dual board array in my big light. You can daisy chain them together even if they have dual connectors, just make sure you go into the right end.
 
TerrapinBlazin said:
So if I were you, I would really want that higher constant current range. Especially the more strips you have. What I really think, after going through the datasheet again, is that you should do 8 strips. At full power they’ll use 200 watts. I think an 8 strip build, and this is when I would break my rule to always wire in parallel. I would do two daisy chains of 4 strips, and parallel them together. That way you still have some redundancy if a strip fails but you won’t have a god-awful octopus of wires everywhere. Get an HLG-240h-54a - the same driver that I have running my dual board array in my big light. You can daisy chain them together even if they have dual connectors, just make sure you go into the right end.
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How did you come up with 200w at full power? If at 500ma they run at 25w and 1amp they run at 50w, wouldn’t they run at about 37.5w if ran at 750ma? Then 37.5 x 8 strips = 300w
 
Oh my bad I thought they were 25 watts at full power. I read the thing wrong. Okay so everything I told you still works, but those calculations are for half as many strips. I always want the ability to run mine at full power. How many strips do you have? Do you have them yet?
 
TerrapinBlazin said:
Oh my bad I thought they were 25 watts at full power. I read the thing wrong. Okay so everything I told you still works, but those calculations are for half as many strips. I always want the ability to run mine at full power. How many strips do you have? Do you have them yet?
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32. 16 3000k (90cri) and 16 5000k (80cri)
 
Yeah so the way I see it you’re gonna be building 8 separate lights. That’s how I would do it. That way you can hang them easily and position them properly.
 
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