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DC Power Supply for Desktop Computers?

Posted by Cliff on from the alternatives-to-the-ubiquitous-wall-outlet dept.

cmowire asks: "Given that inverters waste a lot of power and using solar and battery power is getting to be more attractive given power shortages, are there any DC power supplies that can be bolted in place of a standard ATX power supply and tied to a battery/solar panel combo? I know that it's pretty trivial for a laptop to work like that, but I'm more curious about doing that for a desktop system."

1 of 27 comments (clear)

  1. no power supply needed by dutky · · Score: 5

    The entire point of the power supply in most computers is to convert AC to DC: the components in the computer take DC power directly. If you already have the DC power, you could almost (modulo deriving the right voltage levels and some power conditioning) hook up all the components directly.

    The item (or items) you are looking for is called a DC-DC power converter, possibly combined with a moderately sized capacitor to smooth out any sags or dips (you'll also need something to filter out surges, maybe a zener diode or some such). For most of the computer all you are worried about is producing 5 V and 12 V feeds, which shouldn't be a big deal, but for some components (CRTs and the flourescent backlight on most LCDs) you will need to produce some very high voltages (in the kV range, at least). For high voltages you will need to go back to a real power supply and an intermediate AC stage (aka, a switching power supply, which is what you already have in all such applications). Then the question is, do you replace the one that you already have in your CRT or LCD monitor, which is expecting 50-60 Hz, 110V (or 220 V, or whatever the local flavor is) AC power, or do you roll your own that can take whatever DC voltage you happen to have handy?

    Ultimately, it is probably much simpler just to convert your local DC source into a nice 60 Hz, 110 V AC signal and continue using all your equipment in an unmodified manner. The conversion, both in your DC-AC converter and in the computers' power supplies, is pretty efficient these days, so don't worry too much about lost power there.