LED driver questions

I think I’ve got the driver math figured out but I’m wanting to be certain before ordering parts. My room is 4’8" x 5’ x 8’6" tall. I’m planning on using the Bridgelux BXEB-L1120Z-35E4000-C-B3 strips. I’ve read countless posts on here from @dbrn32 on lighting and I’m hoping I got this correct. To choose driver I look at drivers output voltage divide that with the number of strips and make sure forward voltage falls into the correct min max range? If that’s correct I think I can run 16 strips on two HLG-320H-C1050B or run 10 strips on two of the HLG-240H-C1050B? Is that correct. Can someone please double check my math. I did it all late last night then couldn’t remember how I did it while sober today. Then like magic I remembered again this evening lol. Apparently I’m actually less intelligent while freshly rested and sober lol. Also they only list the data for 700ma and 1400ma I’m hoping I’m correct in the assumption I can split the difference between them for the 1050ma?

I’m planning the whole light fixture to be 4’ x 4’ aluminum angle border with one strip on each side then 12 strips each on their own piece of angle evenly spaced through the inside of the square (if I go the 16 strips direction) . Will that be enough light or will I need to do more than either of those options?

Here’s the manufacturer’s data on the strips to save you from looking it up.

1 Like

So on the HLG-320h-c1050 the CC current region is 152-305. The Molex connectors on the other hand are only rated for 300v. and in all reality, you should only do 80% max load if you’re going to be running it a lot. So I would say aroun 280v or so max. With that you could fit 7 strips on each one for a total of 14. Giving you ~588w.

For a 4x4 I think I would opt for the 320-c1050 r as ther than the two 240h-1050. As you are sitting at 16sqft. And you would be right in the middle of the 30-40 rule, with some pretty efficient lighting.

You would be running them above the 700mA nominal current. So I think you will need to use a heatsink of some type. Anything would work really, some 1" uchannel would work wonders.


@Aolelon got you covered.

Those 1120mm strips don’t exactly fit drivers the best, but certainly can be done. However your math looks skewed a little. On the driver data sheet constant current voltage range is listed, this is the driver voltage you need to use. When sizing leds I generally use typical forward voltage data. If you get to where you’re in the neighborhood of 100% of constant current region voltage is used you do open up the door for a slightly higher than typical forward voltage to screw you and kick driver out of constant current mode. As far as the 80% goes, that’s a basic electricians rule of thumb. The drivers are designed and rated for 100% output over service life.

As far as other stuff goes, I also never select driver with line to line voltage potential over the rating of connectors. And, if you scroll down on the led data sheet there will be a chart that shows the voltage current relationship.

So let’s run numbers. Because of the 300+ volt output I’m gonna ditch the hlg-320 and look at the hlg-240.

238 volts available/ led fv of 40 volts works out to 5.95 means 5 strips will fit. Lots of headroom there so no real reason to account for much else. At nameplate current you’re looking at 42 watts per strip or about 210 watts per driver on led side. Figure another 15-20 watts for driver efficiency loss and the possibility of an over clocked driver would probably put you in neighborhood of 250 watts at wall.

In that configuration you’d be looking at 5,10, or 15 strips depending on amount of drivers you’d want to run.


For higher powered eb strip builds I’ve been going with 560mm strips on hlg-185h-c700a. It’s 14 strips per driver and comes out looking about like this

You gain about 5-6% in efficiency at the lower current, and numbers line up real nice on that build. In your case it doesn’t exactly give you the balance in coverage you’d be looking for though.

What I’d be curious is to how the cost would work out doing 4 hlg-120h-c700a drivers with 10 560mm strips each would work out. The only real issue I see there is cost of power on the hlg-120. It’s literally just a couple dollars cheaper than hlg-185 and only 75% of output. Depending on who may have strips at what price, it’s like $190 in drivers and about $250 in strips. Hlg-120h-c1050a should do about 7 strips if you want to give up that efficiency increase and save $20 or so per light.


Ok as for connector rating I never took that into consideration because I planned to solder and heat shrink all connections but you might be referring to the actual boards connectors. I actually thought about 7 strips initially but when doing the numbers thought I could barely squeeze 8. I’m glad you said use the average rather than min on voltage forward. lt makes more sense to give cushion rather than push them to the limit.

I’m not as concerned over electrical efficiency as much as I am with lighting effectively. Before looking at led I was planning on running two 600 watt HID so anything going this route is cheaper power wise. And electricity is cheap here. Like .06 for off peak and .10 during peak per kilowatt.

As for the smaller strips I looked at those first. Only reason I leaned towards the longer ones was I am planning to use the same frame either way and the larger ones leaves less connections to make. Thank you both for the replies. I’m glad I was at least in the ballpark with how to do it. And @dbrn32 thank you for all the posts on this subject. I wouldn’t even be this far without reading the million other people’s questions you’ve answered.

1 Like

I’ll run the numbers for the 40 560mm and 4 drivers. I don’t think it’ll be cheaper but it might balance out. The longer strips are slightly cheaper but the cheaper drivers would probably even them out.

1 Like

No problem! The 300 volt rating we were talking about is indeed the voltage rating on the strip mounted connectors. You can solder if you want, but I would just use them and wagos for your other connections. Super fast and they work plenty good. There’s no need to even get soldering iron out on these builds. You can do it however you want, but I wouldn’t leave the strip to strip connections as a determining factor using the molex connectors on strips. Will be probably the quickest part of entire build. All you do is depress tab and slide stripped end of wire in then release.

1 Like

You may be correct about the price. A month ago you could get the 560’s for a little over $6 each. Appears they went up quite a bit.

Arrow had a pretty good deal on Samsung f series strips last I knew. Voltage and current would be different, but may be worth checking stock and crunching numbers on them too.

1 Like

Awesome stuff. I’ll run the numbers then order the strips. Can’t afford driver’s until next month but I can get the strips and start building my frame this month. I just didn’t want to order until I was sure on the amount. I’ll check out the Samsung to. At least I’m less worried about the math now than I was before. I wasn’t sure if it was just high me thinking I had it figured out or if I really did lol. :joy:

1 Like

I would expect discount code from arrow within next couple of weeks. For what you’re looking at, probably worth waiting on that.

1 Like

Wait for arrow’s AWESOME discounts. N i missd my 3.60 strip sale db? :joy::joy::joy: hopefully i catch something i cant ignore next payday. I love watching these builds


Probably. Lot of focus right now on import tariffs that largely play into just about all of our components. That coupled with more and more people doing them has increased demand a lot. So prices are up in general, and that 30% off discount for new customers expired.

I think the potential for savings is still there though. The completed fixtures will likely see increases as well.


I’m not having much luck finding the Samsung’s in stock except for at digi key and they’re way to high on price. I’ll watch it over the next few days or up to about 2 weeks. If all else fails I’ll go the Bridgelux route. I’m afraid the longer I wait the worse the price will get. Because of what you said above. I’ve been watching all the tariff stuff and you’re very correct on it hitting the lighting sector hard. Between the electronics and the aluminum heat sinks it’s almost all made in Asia.

To get 28 of those would be $280 versus 14 of the 4ft bridgelux at $216. It would take 25% discount to make them $210 to be comparable in price. Unless they are considerably better light that I could drop the amount needed? I’ve only looked at the numbers on the bridgelux lights so I’m unsure how they compare. Sorry for asking so much. I know you answer a million light questions so I hate adding one more to it.

Voltage, current and output are different on the Samsung strips. You probably wouldn’t need as many of them and probably require different driver.

Gimme a little bit and I’ll look a little closer. Kind of have my hands full at work right now.

1 Like

No rush I’ve got at least a few days before ordering. I will look up the data sheet on them later tonight. I’ve read so much info in the last few days my head hurts trying to process it all.

I should add as long as it doesn’t go up dramatically in price for a worthwhile gain in lighting I’m happy to switch it up. But I’m trying to stay under 500 for led and driver’s etc. Not counting frame basically while getting the most light out of the money. And cheaper is always better with my budget.

So quick math using luminous flux, 40 gen2 eb strips at 700ma has similar output to 22 of these SI-B8U261560WW at 1.12 amps.

1050ma is a standard meanwell output. So let’s look for Drivers to run 22-25 of those Samsung strips and recalculate.

Looks like hlg-240h-c1050a will run 10. Hlg-185h-c1050a will run 8. Hlg-120h-c1050a will run 6.

We should double check with @Aolelon with what you’d need for thermal path there and that my estimation of output from the Samsung strips sound right before you buy anything though


sounds right. The 3500k F-Series are 23fv at 1120mA so you have your numbers correct. I am unsure what you mean about items needed for the thermal path. The single row F-series strips fit really nicely on the .601 profile from HeatsinkUSA for 1$ a foot of Heatsink,