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I'm remodeling my kitchen and decided to get LED strips. I already know the necessary power for my LEDs, but I want to decide whether to power them all from one source or multiple sources. These are the zones

1 zone: 8 meters 120LEDs 5050 double strip (power supply will connect in the middle on the fourth meter to avoid voltage drop) 2 zone: 4 meters 120LEDs double strip 3 zone: same as zone 1

Since the power supplies and wires will be all behind cabinets I have the option to choose whether to power them all from one power source or get three separate ones for each zone.

First scenario will be:

1 power supply 240Watt for zone 1 1 power supply 120Watt for zone 2 1 power supply 240Watt for zone 3

Second Scenario would be:

1 600Watt power supply for zone 1, 2 and 3.

I'm aware that both will work great. 8 meter zones will be connected in the middle to avoid voltage drop.

In terms of price it seems like multiple power supplies is the better option, at least that's what Chinese suppliers on ebay say. I'm pretty sure that the 600 watt must have a fan which may do produce some noise. Some 240W power supplies I've found are with passive cooling so in terms of noise, separate ones might also be better. And if something happens and some of them dies, I can only replace the one that's dead.

What do you think are there any advantages to having one big power supply for all of the leds?

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    If it were my kitchen, I wouldn't buy Chinese power supplies from eBay, but would buy a known name brand that's got a legitimate UL mark showing that it passed UL testing (some cheap electronics have been known to use a fake UL mark). The advantage of multiple power supplies is if one goes out, you don't lose all of your lighting at once (which could be an important factor if the LED's are your primary lighting). I wouldn't get something so large that it needs a fan - fans tend to wear out over time and need to be replaced. – Johnny Nov 6 '15 at 4:22
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I'd go for many smaller ones.

  • Cheaper.
  • Quieter (no fans)
  • Cheaper to replace in case of failure (you just replace one instead of all of them)
  • Better control over voltage drop (you can put each PSU closer to the load to extend efficient mains wires and shorten inefficient 12V wires)
  • Better control over cooling (you can put them farther apart to disperse heat production)
  • Ability to shut down (disconnect from mains) parts of the system to increase efficiency (underloaded PSUs are very inefficient)

Single large PSU is unavoidable for single large load - that's why they're more expensive.

As a side note, I am bit concerned about the "behind cabinets" part. A 240W PSU running at 80% efficiency will dissipate almost 50W on it's own - that requires pretty good access to fresh air. No problem if they are between cabinet and a wall and this space is open at the top and the bottom - they will create enough draft on their own. But if you close the space, they'll cook themselves, greatly shortening lifespan.

  • I'm also concerned about not getting enough airflow. The three power supplies will be as follows: 1. 240W above the cabinets - this should get airflow as it will be on the open although it will be on the top of the room and where all the hot air goes which is a concern on its own. 2. 120W I plan this to go inside a cabinet. It will be a large one as it's on a corner cabinet, but still it is a closed space. Do you think maybe a fan cooled power supply will do better in closed space or I shouldn't put one at all? 3. 240W again this one should be in a lowest to the ground cabinet, but closed. – gvmk Nov 6 '15 at 12:27
  • PSU with a fan closed inside a cabinet won't do much more than circulating same hot air over and over. You need to ventilate the cabinet itself. Look how fridges are built in - they get air vent below them to suck fresh air which connect to air vent between the fridge and a wall (this is where the cooling happens) and then warm air is exhausted at the top. Cabinet doors are rarely airtight, so if you manage to cut a hole at the top and put the PSU near it, it should be fine. – Agent_L Nov 6 '15 at 13:21
  • Great explanation! I will most probably go with putting all three on the top of the cabinets and just run wires to the led strips from there. But how about putting them all below the cabinets? There is usually about 10 centimeters space from the floor to the lower cabinets which is open at the rear. What if I manage to put them there? Do you think that space will have enough airflow? – gvmk Nov 6 '15 at 15:16
  • If you can make some holes at the front and there will be a "chimney" at the back, then it's probably the best place possible. – Agent_L Nov 6 '15 at 15:44

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