CMB24 and power supply

[Scooch]

Looking for some recommendations on power supplies. I am adding 2 CMB24 controllers to run RGB dumb strips.  The total length of the runs is about 75m.  The longest single run is about 45 feet.  The spec sheet says output is 74w/5m. Is that the same as power draw?  Specs also stated 1.2A/m. Any help is appreciated. 

Edited August 25, 2019 by Scooch

[TheDucks]

That is 15W'/M (so their number was very close)

15(W)/12(v) = 1.25A   (all white)  If you plan on running them all white very much, I would use the 80% rule and that would be a PS sized at 1.5A / M 

Other things to consider. 10M is the typical Maximum string length (string wire limiting). So your 45 feet run needs to be done with at least 2 strings

Since you indicated 2 CMB24's, I am assuming 🙄 that you plan on using almost all of the 16 RGB ports for this. and you might want to make this into 2 self contained systems, so the controllers are closer to their LEDS

If you look at PSU prices. They fall into clear price groups as the Watts jump. It is the initial W (in the range) that sets the major costs for the build. So all you really want to avoid is Too Small for your use.

The CMB24 is fused per BANK., so you don't need to worry about additional BANK protection when using a single BIG supply. (you do need to use care as the ports are not protected against over current from that 30A bank)

 

[Scooch]

Thank you for the reply.  When running power to the longer runs would it be sufficient to use a splitter at the center of the run, effectively making it 2 separate strips running off one power lead?  One other question, would 18 gauge wire be sufficient to handle the load?

[TheDucks]

10 hours ago, Scooch said:

Thank you for the reply.  When running power to the longer runs would it be sufficient to use a splitter at the center of the run, effectively making it 2 separate strips running off one power lead?  One other question, would 18 gauge wire be sufficient to handle the load?

That would help with the voltage drop part of the issue, Dumb stings don't care where the connections are.

but. .. A CMB port has a current limit you need to stay under.  (and I must be mis-reading it)  4A per port 12A seems a bit much and there are 3 more RGB connections in the bank. 48A exceeds the bank/fuse rating