COB LED Constant Current Driver Selection Tool


  1. Select a COB from the dropdown
  2. Enter the quantity of COBs
  3. Select a drive current.

The spreadsheet will calculate your total forward voltage and highlight all of the Mean Well HLG-C drivers that are compatible with the parameters you entered. All data is pulled from manufacturer product simulator tools. If the total forward voltage (Vf Total) of your system falls within the rated constant current range of a driver (between V_min and V_max), that driver will turn green, indicating it is a match. I welcome any and all feedback on how to improve this tool – if you notice an error, have a suggestion, or would like to see other COBs or drivers, leave a comment.

Please note that even though big drivers may be capable of driving tons of COBs in series at low current, the high voltage generated by wiring the COBs in series may exceed the rating of your COB holders or connectors (a number of common holders are rated for a maximum of 250V – this would equate to a max of about 7x 36V COBs in series per driver). Always check your equipment specs to verify it can handle the total voltage.

UPDATE 04/17/2017: Citizen CLU COBs updated to Version 6 (F1), Quantum Board 288 and 304 models added.

UPDATE 05/30/2017: HLG-480H-C Drivers added.

UPDATE 06/16/2017: 72V Cree CXB3590 added.


  1. Hey, just got those volt readings for you, 35.47v with the pot cranked up all the way, and 30.22v all the way dimmed.

    • LEDGardener

      January 27, 2017 at 12:37 pm

      Thank you! Hmm, I think I’ll have to use a higher case temperature in the spreadsheet for the higher currents, since the voltage is considerably lower than predicted. I was hoping 50C would be close enough.

      It’s tricky for configurations that are close to the voltage max or minimum, since a few tenths of a volt per COB can be enough to make the difference between a driver being suitable or not. In your case, the tool says a 185H-C1400B isn’t ideal because unless it’s dimmed, the Vf on those 4 COBs would be a touch over 143V. However, at a higher temperature combined with other factors, it obviously works just fine in practice.

  2. Great spreadsheet by the way, thats pretty slick, just plug in the info and there you go, good stuff man.

  3. Hey, what do you think about these power supplies? They are cheap and it looks like they only have a voltage adjustment though.

    • LEDGardener

      March 10, 2017 at 6:56 pm

      Those would work just fine. I only use the voltage adjustment on my constant voltage driver and just leave current cranked anyway. Only thing is that you can’t easily dim them… For $50 less than an HLG-320H-C, that might be worth it though.

  4. Hi, I have selected 4 cree 3590 cobs 36V, and HLG-120H-C turns green. This driver is for each cob or with this one can supply all cobs?


    • Hi there. The 120H is capable of powering 4 of those COBs at 700mA and 1050mA. If you bump up to 1400mA, you’ll need a bigger driver.

  5. Not like you don’t have enough on your plate, but any plans to add the higher wattage Mean Well drivers (HLG-480H-Cxxxx) to this spreadsheet?

  6. Wow, dude – you don’t f- around… sweet, thank you!

  7. Beau-Jacob Eaton

    June 16, 2017 at 2:41 am

    Hey there,
    Awesome tool!! Just wondering if you are able to include the Cree CXB3590 72 volt.
    And thanks for all your helpful info.

  8. Can you add cree cxa1304 please?

    • LEDGardener

      July 6, 2017 at 10:42 pm

      Hey Limsleia, sorry – that COB takes very low current so none of the currents I have built into my spread sheet will work. I’m happy to help you match a driver though if you need a hand.

      • Ah. Yeah it is extremely cheap! $1.10 per cob. I have no income so buying 35-45 dollar chips is out of hte question but if I can do something for around 40-50 dollars total thats my goal for a build. As much light as possible for 40-50 bucks. What do you think?

        • LEDGardener

          July 6, 2017 at 11:45 pm

          50 bucks including heat sink and driver?

          • Not including the driver but still need driver recommendation. Thanks for humoring me. Am disabled and have no income as of yet so trying to find a way to gradually move away from terrible chinese leds i got for free that are hurting my growing in alot of ways.

          • LEDGardener

            July 8, 2017 at 8:35 am

            The best budget COB in my opinion is the Citizen CLU048-1212. They can be had for like $12 each. Pin fin heat sinks for them are about $12 each as well.

  9. A question pls… can i mix 50w cobs and 5w cobs wiring them To run on the same driver ?

    • LEDGardener

      July 24, 2017 at 8:27 am

      If it’s a constant current driver and both the COBs are rated to take the same current then it’s fine. E.g. – if you have 50W COBs and 5W COBs and they can both take 700mA, you can hook them both up to the same 700mA driver.

  10. Ronald Mosely

    July 31, 2017 at 4:41 pm

    Using the calculator how do you know which to choose for the Vero 29SE. Attempting to run 8 of them on 2 drivers at near max.

    • As far as voltages go, the Vero SE units are the same as the Gen 7 – it’s really only the case that’s different. Just use the Gen 7s in this calculator and the results will be the same for SE.

      • Ronald Mosely

        July 31, 2017 at 6:01 pm

        Thank you for the timely response you’re awesome

      • Ronald Mosely

        July 31, 2017 at 6:11 pm

        If i am running 4 in a strip 2 3500k and 3000k which driver would be best as far as output and efficiency is of concern. not quite understanding the math when pairing a driver for output and efficiency.

        • LEDGardener

          July 31, 2017 at 8:08 pm

          The closer the load is to 100% of driver output, the more efficient the driver will be. You can estimate how efficient the driver will be by looking at the spec sheet for the driver you have in mind. If you scroll down a few pages, Mean Well includes charts that plot load vs. efficiency at different input voltages.

          The driver you’ll need for your 4 Veros will depend on which flavour of Vero you get. The B and D versions are the most popular of the three.

          If you go with the D version, a very efficient match would be the 185H-C1400. If you go B version, its tougher to line up with a driver for high efficiency. To get the same power as the combo above, you’d need a 240H-C1050 and a load of 4 Vero B’s wouldn’t push the driver hard enough to get that same driver efficiency.

          • LED Gardner how do i determine the watt per light or for 4 Vero 29 per driver Meanwell HLG -185-C1400b?

          • LEDGardener

            August 9, 2017 at 10:17 pm

            Watts is voltage * current. If you know the current (e.g. – 1.4 Amps), you can find out what voltage will be across each COB by looking at the data sheet or using the manufacturer product simulator.

            The Vero 29 voltages will be different depending on which model you use (B, C, or D)

  11. LED Gardner thank you for the previous information but i am in the process of uptaking a new project and would like to consult with a knowledgeable person before i continue forward. So i had previously bought some cheap LED lights the viparspectra 700 dimmable, i just recently took one of them apart and have discovered that it has 6 drivers. there is not much on the drivers but the model number which is chinese. The voltage: 50 -70 V DC and the current 700MA. With these 5 drivers what COB LED could i possibly power and how many as this unit is actively and passively cooled . Would like to stay in the realm of bridgelux. Any information would be more than helpful. Once again thanks in Advance.

    • LEDGardener

      August 13, 2017 at 3:45 pm

      Hi Ronald, Is be happy to help – can you please make a thread in our COB forum for this? I’d like to collect all the questions like this in one place so everyone else can benefit from it as well. Plus, there are some smart cookies on the forum as well that can help.


  12. Hey LEDGardener,

    I was wondering what the difference is between the Total Power (W) vs Max Power (W)? If I were to run 3 Bridgelux Vero 29 Gen 7 B at 1400mA, would I be getting 210.4W (Power Total) OR would I be getting 320.6W (Max Power) using the Mean Well HLG-320H-C1400? Thanks again for your help. Your youtube videos and this website with the Driver Selection Calculator Tool are PRICELESS. Thanks again!

    • LEDGardener

      August 20, 2017 at 12:56 am

      Hi James! The total power is the wattage that the COBs you’ve selected will draw at the current you picked. Max power refers to the rated max power output of each driver. Your Veros would only be drawing 210.4W even though the driver might be capable of outputting 320.6W at maximum. Glad you’ve found this tool helpful!

      • Thanks again! I know I’ll be counting on you, your site, and this forum to help me along with my future build. I’m brand new to this stuff and it’s been challenging but hopefully it’ll pay off! Thank you.

        • LEDGardener

          August 20, 2017 at 1:11 pm

          It most certainly will pay off. I’m always happy to help and the guys in the forum are a great resource too. If you have any questions, feel free to ask!

  13. Hi Mate, great calculator, much appreciated thanks! Im going to fill a 4×4 area and was looking at 10no CLU048 1212s running at 1400mA – is this suggesting i can get away with 2 HLG-480-C1400 to get 960w output from 500ish at the wall?

    • LEDGardener

      September 1, 2017 at 9:55 pm

      Hey Will! Those COBs will only draw 50W each at 1400mA so you could do this off of 2x 240H-C1400 drivers. This would be a very efficient build because 5 of those COBs is practically maxing out 1 of those drivers so it’s perfect. Total wattage would be 500.

      • Cheers mate! Yeah that makes sense, although ive read i need approx 50w sq/ft so need another 5 of those to get a decent coverage? 16sqftx50w = 800w req
        Thanks again!

  14. Hello.
    Just found a driver LPV-35-36. This would be perfect for one 36v COB @ 1000ma, right? If i`d like to run one?

    • LEDGardener

      September 6, 2017 at 8:28 am

      Most COBs will try to pull more than 1000mA when driven constant voltage at 36V like this driver does. I’m not sure what will happen with this particular model if the current draw exceeds it’s supply capability. I know you’re safe on the HLG series but I can’t say the same for the LPV.

  15. found your site about 24 hours ago and now I am almost ready to take the plunge, will be my first grow and your driver selector tool has almost given me the confidence to hypothesize different setup, the first thing i want get away with is the veg lighting as i already have seeds that are popping so my question will pertain to that, for me space is not a problem the only problem is powerback up as there are constant outages where i live ( third world developing country) so i want to have the most efficient setup, for my veg room i will have a constant power back up of about 1200-1500 watts
    I was thinking of running clu_48 @ 700ma , according to your calculator hlg 240h c700 will run 10 of these…is it a good idea to run the clu_48 @700ma? I could start with about 50 cobs and 4 drivers
    second option is to run clu_48@1080ma hlg 320h c1050 will run 8 of these ( or maybe 9 as its only 4 volt shy of the required 309 volts.
    please advice as I am all set to order the cobs and drives, these cobs at 10 bucks a piece are hard to beat…or are they?
    for my flower room I will look into vero 29 gen 7 but first things first 🙂
    also do you thing elg 240 h c700 will be able to run at the same spec as hlg 240 ( I am in 220v country)
    Thank you once gain for putting all this together

    • LEDGardener

      September 6, 2017 at 6:42 pm

      Hey man. One thing to keep in mind with this many COBs is that there will be a voltage limit on the COB holders that will likely constrain the number of COBs you can run in series. For example, the big Ideal Chip-Lok holders are rated for 250V, so this works out to about 7x 36V COBs in series. You may have to base your calculations around this. I think running a veg room at 700mA is a great idea though.

  16. LEDGardener

    September 6, 2017 at 6:45 pm

    And the ELG is very similar to the HLG on 220V power (the whole series is actually rated for a lower output power on 120V for those of us in North America, unlike the HLG which is the same for both voltages). At 700mA at 220V input voltage, the output voltage range on the HLG is 13V higher than the ELG.

  17. Password protected spreadsheet! Not fair! And I have no desire to reinvent the wheel. LOL
    I’d hoped to be able to add some of the Samsung H-Series GEN3s to the table just play around with. This is a cool little tool. Very nicely done.

    • LEDGardener

      September 29, 2017 at 5:01 pm

      Thanks Lonn! Those strips would almost need their own tool since there are so many different versions and configurations you can wire them up in. I’ve toyed with the idea of creating one though. How big of a light are you considering building?

      • I became interested in the LED strip cobs as a replacement for the 8′ T12 fluorescents in my tattoo shop, but the more I looked into them I wondered if they could be used for growing. I ordered eight of the 4′ 5000k 80 CRI lights and a Meanwell driver to experiment with. If it works I have an alternative to my Cree CXB3590 system. If it doesn’t pan out the shop has new lights so I really can’t go wrong.

        8 x SI-B8R221B2HUS H Series GEN3
        1 x Meanwell HLG185H-C1050B

        Using 22.5Vf the system will have a total forward voltage of 180V at 960mA. That should be a good match to the Meanwell driver and return an efficacy of 192 lm/W for a total of 33,248 lumens if my math is right. (Cap’t Morgan may have been involved) That’s similar to a four cob CXB3590 36V system running at 1.5A, but the cost is less at the same level of light. Once I get everything in and assembled I’ll run my PAR meter under it and see how it performs.

        • LEDGardener

          September 30, 2017 at 11:24 pm

          Awesome! My calculations say you should get a Vf of 23.2 per strip at that current, resulting in a total of 185.6V, which, as you said, is an excellent match to that driver. Nicely done and please share your PAR results.

  18. This doesn’t have drivers like the hlg-240-48a or anything like that 🙁

    • LEDGardener

      October 7, 2017 at 6:21 pm

      This is the constant current tool. The driver you mentioned is constant voltage. I have a calculator for that as well.

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