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Direct current power supply / led canless lights

Kyle Bentley | Posted in Green Products and Materials on

Does anyone know of a system that uses a central AC -> DC power station, so that several led candles lights can be ran without an inverter at each light?  It seems awfully inefficient to have every light responsible for its own power conversion, not to mention a pain to wire.

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Replies

  1. Chris D | | #1

    I can't help with particular brands/systems for this, but I know that what you're looking for is available. I have seen them for sale; they usually look like a normal industrial/commercial power supply (for computers, PLCs, whatever), with a metal chassis and terminal strips for DC wiring connections.

    They need to be compatible with the voltage and current requirements of the lights they are powering, and would need to run LV (low voltage) wiring between the power supply and the distributed LED lights. I don't know if individual control of lights is possible, as much as single group control of all lights connected that power supply, etc.

    I just did a quick Google search and found a few products like this, for example:
    https://www.visalighting.com/ps24-led-power-supply

    Individual power supplies makes things easy to retrofit or easy to wire in the normal methods of distributed AC wiring, and can give individual device control, but you're correct that there's really no requirement to have a single power supply per LED fixture.

  2. Expert Member
    Zephyr7 | | #2

    If the power supplies (which aren't inverters if they are running AC->DC, BTW, inverters go from DC->AC) are properly sized, the efficiency will be the same. As an example, consider a 10w light with an 88% efficient power supply. That light's supply will be losing about 1.36 watts as heat. Now consider ten 10 watt lights running from a common 100 watt power supply with the same 88% efficiency. That central power supply is losing about 13.6 watts as heat -- exactly 10 times what the small power supply is losing running one light. There is no difference between the two configurations in terms of system efficiency.

    The difference would be if you have power supplies at each fixture capable of running multiple lights. Power supplies typically operate a lower efficiency when running at less than full load, so you would gain efficiency by running multiple lights off of a common power supply IF that lets you get that common power supply up to a higher percentage of it's rated capacity.

    I don't really see a different in terms of wiring since you're going to have to run a cable between all the light fixtures regardless. Note that DC is more of an issue to switch on and off compared to AC, so there are some other considerations here like the ratings of the light switches if you want to use a centralized DC power system.

    Bill

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