Looking for a sanity check on my first LED strip build

Hello folks, I started planning an LED build quite some time back, then had to put it on hold. I've just come back to it, and I'm now second-guessing the plan I'd made. I'm a complete noob as far as LEDs go, and hoping someone could give me some guidance before I go ahead and spend a bunch of money (and maybe start a fire!)

I was looking to use 16 Bridgelux EB Gen 3 strips (Vf 20.3V, test current 960mA, https://www.digikey.co.nz/en/products/detail/bridgelux/BXEB-L0560Z-40S2000-C-C3/13181804 ), and an HLG-320H-42A driver ( https://www.digikey.co.nz/en/products/detail/mean-well-usa-inc/HLG-320H-42A/7704044 ). The idea was to wire pairs of strips in series for 40.6V per pair, then wire the 8 pairs in parallel.

Re-reading the datasheet for the driver, I'm a little unclear on how it actually works - it has pots built in to control both current and voltage, but I'm thinking it's not as simple as setting them both and Bob's your uncle...

Is this plan somewhere near making sense, or just completely wrong?

Thanks for your time!

justsomeguyiguess said:

Hello folks, I started planning an LED build quite some time back, then had to put it on hold. I've just come back to it, and I'm now second-guessing the plan I'd made. I'm a complete noob as far as LEDs go, and hoping someone could give me some guidance before I go ahead and spend a bunch of money (and maybe start a fire!)

I was looking to use 16 Bridgelux EB Gen 3 strips (Vf 20.3V, test current 960mA, https://www.digikey.co.nz/en/products/detail/bridgelux/BXEB-L0560Z-40S2000-C-C3/13181804 ), and an HLG-320H-42A driver ( https://www.digikey.co.nz/en/products/detail/mean-well-usa-inc/HLG-320H-42A/7704044 ). The idea was to wire pairs of strips in series for 40.6V per pair, then wire the 8 pairs in parallel.

Re-reading the datasheet for the driver, I'm a little unclear on how it actually works - it has pots built in to control both current and voltage, but I'm thinking it's not as simple as setting them both and Bob's your uncle...

Is this plan somewhere near making sense, or just completely wrong?

Thanks for your time!

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All seems good to me. A type version has two internal pots, hidden away in some accessible with a small screw driver. Be careful the mecanism can break.
Voltage dimming works by adjusting voltage: dimming is much more drastic than by current. Its main functionality for our use it to set a ceiling: you wont be able to current dim to over this ceiling. Also, if you were to have half the strips go out in someway then you wont have the rest over powered and burnt out. Way to do this: turn both pots up to max. Then, either by eye or by measuring current: slowly bring voltage dim down until you see light/curretn decreasing. Do this when you hav had the rig on for a while: forward voltage goes down a bit with temps.
As for current: youre likely to hit slightly more current with these, maybe 10% more or so. Generally they give a bit more than spec, if you go onto the the meanwell web, find your driver and look for report next to datasheet youll find the actual numbers it puts out. Happy growing

Edit: you probably need some heatsinking.

Just set the voltage to max and use the current dial to dim. If the current is limited the voltage will reach a certain level, decreasing the current further also reduces the voltage. Its Ohm's law.

I would recommend to get a B or AB type power supply. Then you can add a potentiometer to use for dimming. It's much simpler to control and doesn't cost much extra.

Lou66 said:

Just set the voltage to max and use the current dial to dim. If the current is limited the voltage will reach a certain level, decreasing the current further also reduces the voltage. Its Ohm's law.

I would recommend to get a B or AB type power supply. Then you can add a potentiometer to use for dimming. It's much simpler to control and doesn't cost much extra.

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Hello again Lou. Please explain the benefit of running the driver on max voltage, 46ish V, when OPs circuit only requires 40.6V. I only see downsides, higher power consumption (by about 12%) and no safety benefits if he sees string failure. Also 12% more power consumption will mean a hotter running driver.
If he trims down voltage to just above 40.6V OP can protect his strips from overcurrents in case of string failure since they wont be able to draw more current than the voltage allows. It wont affect how much current the driver gives, only max draw per strip.

I do agree on the B or AB type driver, its probably a better solution in OPs case.

Awesome, thanks for the replies! Appreciate the playlist Medicinal, I recall reading a bunch of stuff on LEDGardener when I was planning this originally, but apparently I didn't dig deep enough to find all the goodness. I'm about to dive into that.

I'll definitely look into the B or AB driver, simple sounds good to me and I'm happy to pay a little extra for that - mostly just want to make sure I only spend the money once, and don't subsequently set that money (and my house) on fire!

As for heatsinking, I'm planning to use aluminium flat bar to mount the strips, I figure that should cover heatsinking and support in one go. If it turns out not to be enough, I may add some small L profiles along the top of each bar for more surface area.

Edit: Rocket Soul, just to clarify, did you mean heatsinking for the strips themselves, or for the driver? I'll be running it near its capacity, so I guess it'll be making some heat itself.

Thanks again folks, appreciate your input.

justsomeguyiguess said:

Awesome, thanks for the replies! Appreciate the playlist Medicinal, I recall reading a bunch of stuff on LEDGardener when I was planning this originally, but apparently I didn't dig deep enough to find all the goodness. I'm about to dive into that.

I'll definitely look into the B or AB driver, simple sounds good to me and I'm happy to pay a little extra for that - mostly just want to make sure I only spend the money once, and don't subsequently set that money (and my house) on fire!

As for heatsinking, I'm planning to use aluminium flat bar to mount the strips, I figure that should cover heatsinking and support in one go. If it turns out not to be enough, I may add some small L profiles along the top of each bar for more surface area.

Edit: Rocket Soul, just to clarify, did you mean heatsinking for the strips themselves, or for the driver? I'll be running it near its capacity, so I guess it'll be making some heat itself.

Thanks again folks, appreciate your input.

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For the strips. Especially if its the slim version, thise are very flimsy and can break aswell.

Gotcha, cheers!

Pcb feet standoffs are good to use so the driver isn't flush mounted. They will help passively cool the driver a bit more.

justsomeguyiguess said:

Awesome, thanks for the replies! Appreciate the playlist Medicinal, I recall reading a bunch of stuff on LEDGardener when I was planning this originally, but apparently I didn't dig deep enough to find all the goodness. I'm about to dive into that.

I'll definitely look into the B or AB driver, simple sounds good to me and I'm happy to pay a little extra for that - mostly just want to make sure I only spend the money once, and don't subsequently set that money (and my house) on fire!

As for heatsinking, I'm planning to use aluminium flat bar to mount the strips, I figure that should cover heatsinking and support in one go. If it turns out not to be enough, I may add some small L profiles along the top of each bar for more surface area.

Edit: Rocket Soul, just to clarify, did you mean heatsinking for the strips themselves, or for the driver? I'll be running it near its capacity, so I guess it'll be making some heat itself.

Thanks again folks, appreciate your input.

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I suggest AB type dimming, it will give you max flexibility and it's only a dollar or two more.

Rocket Soul said:

Hello again Lou. Please explain the benefit of running the driver on max voltage, 46ish V, when OPs circuit only requires 40.6V.

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That is not how it works.

U = R*I

With R set (the fixture) and I limited (by the supply) U is just the product of the two.

Please learn some basic electronics before you go to other people and explain the world to them.

Thanks for the reply Lou. Just wanted to check that I'm following what you're saying - this means that the resistance of the fixture will be constant(ish - varying with the temperature of the strips), and the driver (assuming it's constant current) will provide, well, constant current, therefore the voltage that the fixture sees will be determined by those factors, rather than the driver itself, right?

I haven't had time to get through the whole playlist that Medicinal linked yet (busy times here, bloody typical!), but I'm hoping between this thread and that tutorial, I'll finally have a proper grasp on how this all works. Fingers crossed!

Lou66 said:

That is not how it works.

U = R*I

With R set (the fixture) and I limited (by the supply) U is just the product of the two.

Please learn some basic electronics before you go to other people and explain the world to them.

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Do you really think that this is how you apply Ohms law in this case? Yes, i know it, its not even high school level, here we learn it when were 14.

So you mean if you run a 42V CONSTANT VOLTAGE driver at half its rated current it becomes a 84V driver? Good luck. Im not engaging in this with you anymore. Give the reason why OP should run it with voltage dim on max voltage dim or go home. Youve not addressed the issue raised with the advice in your reply.

justsomeguyiguess said:

Thanks for the reply Lou. Just wanted to check that I'm following what you're saying - this means that the resistance of the fixture will be constant(ish - varying with the temperature of the strips), and the driver (assuming it's constant current) will provide, well, constant current, therefore the voltage that the fixture sees will be determined by those factors, rather than the driver itself, right?

I haven't had time to get through the whole playlist that Medicinal linked yet (busy times here, bloody typical!), but I'm hoping between this thread and that tutorial, I'll finally have a proper grasp on how this all works. Fingers crossed!

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The driver in question is constant voltage driver with constant current region between 21V to 42V. You can check up on this with meanwell. It works exactly like Lou and you explain in this region. Above 42V it works as a constant voltage driver. It will output around 46V on max voltage dim as per the report sheet on the meanwell website: https://www.meanwell-web.com/content/files/pdfs/productPdfs/MW/HLG-320H/HLG-320H-42-rpt.pdf
And this voltage is constant and set by the driver no matter what output current you set it to.

Turning voltage up to max wouldnt really affect your build but it would be running the driver at a higher power level; youd have higher power consumption for no good reason, your running the driver with a 5V extra (the required voltage is about 41V for 2 strings in series) which means higher power consumption.

What i explained earlier on is a safety feature of this type of driver which protects your build: it limits the output voltage to just above the required voltage necessary for the drive current of each string at the drivers max current output. It means that in the case you lost some strings the light will continue drawing the same amount of current per string instead of the remaining strings drawing more current per string. If you have a bit of extra over voltage then each string will draw more current, effectively sharing the current over less strings> higher current per string.

Its not really a big deal, those strips have a fairly high max current so its not super necessary. If you dont want to bother about trying to figure out who of us two is correct you can just leave the voltage dim where it is, it will work fine. But turning it up to higher voltage will increase your power consumption, remove the safety feature and give you zero benefit.

It may be that my explanation is hard to understand. Here @Prawn Connery is talking about the same thing, maybe it makes more sense:

I dont really care what you do, but its shitty if you get bad advice due to someone harassing my replies. Lou is close enough to right to not be able to understand that hes wrong unfortunately.

I'm about to go to work, so I don't have time to give this a proper read and response right now, but I want to say two quick things: 1) I appreciate the concern (from both of you), and I'm guessing that I've stumbled into something that's been going on between you for a while. 2) I won't be acting on this plan until I'm confident I've understood the whole thing properly - I'm taking all of this advice to guide my learning, not my decision making. Once the learning is complete, then I'll make the final decisions.

Thanks again for your time and input!

justsomeguyiguess said:

I'm about to go to work, so I don't have time to give this a proper read and response right now, but I want to say two quick things: 1) I appreciate the concern (from both of you), and I'm guessing that I've stumbled into something that's been going on between you for a while. 2) I won't be acting on this plan until I'm confident I've understood the whole thing properly - I'm taking all of this advice to guide my learning, not my decision making. Once the learning is complete, then I'll make the final decisions.

Thanks again for your time and input!

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1: this is fairly recent but regular enough for me to notice the pattern.
2: you can take the advice that we both agree upon: B or AB-type driver is preferable in your situation. I love DIY, its a really fun experience. First time you turn it on, go 'Gawd its bright' to yourself, first time you outgrow your best results, totals or g/w: its frigging awesome. Id hate for this to stop you from moving forward.

If you need help, just ask, theres a lot of people who can help you.
Best thing would be to mention what space youre trying to light.
Also, the strips youve linked to is the are the thrive version of the EB strips; the have a special chip that uses a deeper blue pump around 440nm. Not very efficient but an interesting spectrum with double blue peak, similar to the HLG Diablo spectrum, but much less efficiency. Normally around here when people talk about the eb gen 3 theyre talking about the regular eb strips with a standard 450 nm blue pump.

justsomeguyiguess said:

Thanks for the reply Lou. Just wanted to check that I'm following what you're saying - this means that the resistance of the fixture will be constant(ish - varying with the temperature of the strips), and the driver (assuming it's constant current) will provide, well, constant current, therefore the voltage that the fixture sees will be determined by those factors, rather than the driver itself, right?

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Correct, your understanding is good. And Rocket Soul is absolutely correct about setting the voltage slightly higher than needed for max power. It will limit the max current drawn by each strip if one or more strips fail.

justsomeguyiguess said:

the voltage that the fixture sees will be determined by those factors, rather than the driver itself, right?

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Ye, that's how it works. All within reason of course. At some point the driver can't deliver the voltage that would be required.

Rocket Soul said:

It may be that my explanation is hard to understand. Here @Prawn Connery is talking about the same thing, maybe it makes more sense

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You did read that? He says they use the Mean Well constant current drivers above their rated voltage for extra power (and without burning their fixture as a constant voltage would do).

Lou66 said:

You did read that? He says they use the Mean Well constant current drivers above their rated voltage for extra power (and without burning their fixture as a constant voltage would do).

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Um, what? Please quote what you actually read cause at nowhere is he saying this. And in any case, how does that relate to your advice: voltage dim max?


"If you want to run them in parallel, then you need a 54-60V constant voltage (CV) driver. If you plan to run at lower currents, then a CV 54V driver will work – esepcially if you run a Mean Well A or AB type driver that will output well above 54V.

The XLG-320-H-AB will work, but I'm not a huge fan of the XLG series as they are a constant power driver, which means they adjust both current and voltage to match desired wattage instead of being able to current limit or voltage limit the driver – which is an important consideration when wiring in parallel, because you can voltage limit the driver to prevent thermal ruanway in the event one of the boards becomes disconnected."

This! With a meanwell hlg Constant voltage driver with A type dimming, you can limit the voltage so that each string can only draw a certain current. If you set it up like i described you get a parallel circuit where losing some string will not make the remaining strings draw more current than they would in the original configuration.

You can also use the voltage dim to hit higher voltages, as in this case with a qb648 that needs about 56V; you could reach that with a 54A type meanwell.

For the 3rd time, please describe the benefit of your advice: setting up the driver to max voltage dimm so it outputs 46V when only 41V is needed.

Rocket Soul said:

setting up the driver to max voltage dimm so it outputs 46V when only 41V is needed.

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It does not output 46 V because it is current limited.