LED Driver not producing full power, please help


I recently got two of these setups for my indoor garden:https://www.alibaba.com/product-detail/Top-sale-800leds-samsung-lm561c-s6_60718595185.html

I’ve been running one of them for approx. 3 weeks and the other one I plugged in last night. While doing some watering today I noticed the driver (Meanwell HLG-320H-48B) for the newly installed light was just warm, not hot like the other driver after it’s been running for an hour or more. When I realized the driver wasn’t producing nearly as much heat as it should I took a look at the panel and realized it’s only producing approx. half as much light as the other one.

I don’t even have the dimmers connected to either driver so both lights should be running at 100% by default but the newly installed one just seems to be running at half the power.

I have been trouble shooting for nearly 3 hours; trying different sockets, unplugging it for a while and waiting before plugging it back in, I also wired up the dimmer to the driver in question but it still just produced half the light while set at 100%. I also switched the wires to each of the drivers so they would run the opposite panels and I’m sure now it’s an issue with the driver in question because it will only produce half of the power regardless of what panel it’s wired to. The other driver has no problem running both panels at full blast, so I know the panels aren’t to blame.

Any advice, knowledge, or input that anyone can offer would be much appreciated. I imagine it’s extremely rare that a Meanwell driver would be faulty out of the box so perhaps there’s something I haven’t considered.




What made you order the Meanwell driver? When selecting an LED driver you should take a few things into consideration. LEDs are devices that are operated by current , and the forward voltage can differ. That being said a constant current option is what will mostly be used for these type of applications. What you need to take into consideration is the forward voltage, forward current, and the maximum power. Given the voltage and the current of the device you give that would put you at about 372 watts for maximum power. The driver you gave is for 322W max, so that may be causing an issue. I looked through our system and I was not able to find an option for an LED driver that has a higher wattage that meets the forward voltage. Since we do not know the design of the circuit, there may be other things to take into consideration as well. I do hope this helps and please feel free to contact us at anytime.


Thank you for the input. I still do not understand why the one driver would run at seemingly half power if they are identical setups though. I mentioned as well that I tried the other driver on the panel that the faulty one was wired to and it was much brighter, so that rules the panel out as the problem and it seems the issue is specific to the one driver, not both.


It may be an issue with the one driver. If you hooked your other driver up and it worked fine, that pretty much narrows it down. You may want to look into getting a replacement driver. It is hard to trouble shoot the specific driver from our end. Based on the information that you provided that is where I would start.

Thanks, Bobby

Mean Well Driver is humming, is that normal?

Hello @MustardTiger,

I did speak with my product manager for MEAN WELL and he confirmed that you should not have to use the dimming circuit for this product to function properly. It appears that you have properly checked the driver against both panels and it appears that you have a faulty driver. At this point I would suggest contacting our customer service depart at customer.service@digikey.com with your order information and they can walk you through the process of getting you a new driver.


Thank you for helping me confirm it is an issue with the driver.

I ordered the driver as part of a kit from a company overseas. I do not have faith in them to replace the item or provide a refund (I am speaking with them currently but they don’t seem willing to help). Is there any help I can obtain from Meanwell?

Thanks again for your response on the matter.


MEAN WELL has a Contact US Page on their site. You would need to contact them as we would only be able to help with parts that are purchased through Digi-Key.


Thanks a bunch!


Hey, was hoping you could answer another question.

Are the drivers supposed to get “really hot” after being on for a few hours? The one that seems faulty just gets warm and I can hold it without a problem. The other one that puts out more light is very hot and I can only hold it for a second or two before it’s too hot to bear, but from what I understand they are supposed to run hot if going at max output.



The cases of these can get fairly hot. There is an load output vs Tcase in the data sheet. Most of the time they do not run as hot as you are describing, however you are running them at 100% load. My main concern at this point since your overseas disti is not working with you would be weather these are valid parts or not. If there are not you may be running a risk using them if they are not designed with proper safeguards in place.

Also make sure you have all of the proper certifications listed on your part. You should be able to verify a serial number/lot number with MEAN WELL when you talk with them to ensure you have valid parts.


I ordered a similar kit from a China based company. 2x 300w panels with HLG-320h-48B’s. Mine only drew about 260w when I first hooked them up. I contacted the company and they were no help.

Even though they’re labeled as B type, they have the current adjust pot built in. (Like they’re actually AB type…is there supposed to be a difference in the label?) I opened them up to 320w each and all is well. Hope this helps someone.