LED Strip, PSU, and DMX Technical Questions

I'm looking at buying a house-lot of LED strips from you. I like your helpful website, and the products appear to be of good quality. There are a couple of things I was hoping you could clear up for me.

- The Fivespect 24v strip data sheet says that it draws 36 watts for the two whites and 24 for each color. This is a total of 144 watts for the reel.

- However, it also says "max simultaneous power/ft" of 10 watts. This would be 164 watts for the reel.

- Then you recommend your 120-watt power supply, which doesn't seem like it would be enough.

- But you suggest 3rd party power supplies should be 60 watts?

- I'm guessing I'm missing something here.

And then my next question is about your Centric Home 24v. It says it has a total of 90 watts. Is your dimmable power supply, which is limited to 96 watts (to meet class 2) enough? As this is not as much headroom as I see is normally recommended (20-30%).

And then your DMX controller. It appears that these can be daisy-chained with ethernet-style cables, but I just wanted to check.

We agree that the power specifications on the FiveSpect product are a bit confusing - we hope we can help clarify, and perhaps work on this internally for clarification in the future.

​First of all, the specifications are offered under the assumption that the product will not necessarily be used as an entire reel, so your calculations and power supply limitation concerns are correct and valid.

Specifically, we would not recommend using our 120-watt power supply if you intend to operate all channels of a full reel of the FiveSpect LED strip lights, and at full brightness.

​The 60-watt power supply recommendation for a full reel is based on the assumption that the maximum power draw will be limited to 1.5 amps for the white (T/D) channels and 1.0 amps for the color (RGB) channels. This would be the case for most installations where brightness is maintained across color temperature dimming. For example, to maintain constant brightness from 2700 K to 6500 K, the channels would always need to add up to 1.5 amps, and never exceed it, even at the mid-point color temperatures.

Looking at the numbers, however, we're not sure how the 10 watts per foot limitation adds up, given that the individual circuits simultaneously powered at full brightness would still be less than the 10 watts per foot level. 

​Regarding the Class 2 power supplies, you are correct that the extra headroom in power supply capacity is commonly recommended. On the other hand, we do have quite a few of these dimmable power supply units in service, and we have not had any issues with power supply capacity, so we believe that with robust and reliable power supply design, these units fare quite well even when driven close to their 96-watt limit.

Finally, we can confirm that the DMX decoders can be daisy-chained via the RJ45 ethernet ports.

I have another question, and I have done a bit of research, and I am a bit of a nerd, but I thought I'd ask.

I'm wanting to put some of your home LED strips on my ceiling. They will be in a black aluminum channel, with a black diffuser, in the negative detail between sheets of plywood. 

It looks to be the same channel as the one you sell, but in black. The fact that the diffuser is black means it blocks a lot more light (I've seen varying claims between 40% to 65% are blocked).

Given that the channel will be recessed into the ply, and that the black diffuser stops more than normal light energy, do you think I could have any problems with heat? And by problems, I mean the plywood, and the LEDs themselves.

Also, I see you say that they normally reach 30 degrees C over ambient temperature. I assume this is not in a channel?

While we have not tested this specific type of diffuser installation, we completely agree in theory that it would be more likely to heat up a bit more than a translucent diffuser. A common misconception is that only infrared energy can carry heat; all wavelengths are capable of generating heat upon irradiance on a surface.

​That being said, we can't imagine the diffuser would absorb so much of the optical energy that it would heat significantly. As a rough ballpark estimate, we would say < 15% of the total system energy would be absorbed by the diffuser material. Our estimate is based on 70% efficiency loss in the LED strip itself (only 30% emitted as light), and a very rough guess that no more than half of the emitted light ends up being absorbed by the diffuser based on the transmission specs you provided.

The 30-degree measurements are based on the LED strip without the aluminum channel, so while we don't have the measurements, we expect that the temperature rise would like to be lower when used inside an aluminum channel.

If at all possible, we would recommend testing to verify all of these points, before any permanent installations. 

If I want to power your 5-color strip via the DMX controller, I assume your 200-watt power supply would be suitable. (in case someone puts all colors up full) I only ask as you market it specifically for your Photon panel. 

Yes, while it isn't being offered specifically for the FiveSpect product, the PhotonPanel power supply is certainly compatible and could be a good way to ensure sufficient power capacity.

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LED power suppliesLED strip lightsDMX dimmers

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