Watts Up?

Just plugged my server, monitor, modem and router into a Watts Up watt meter borrowed from Berkeley’s Sun Light And Power. The goal is to see how much power this machine chews in a month, then purchase solar cells, inverter, and battery backup to match or exceed. Going by initial conversations, should be able do this relatively affordably, even without feeding power back to the grid (if you want to see your electric meter turn backwards, the investment swells considerably — we’ll start small).

Music: Velvet Underground :: Some Kinda Love

6 Replies to “Watts Up?”

  1. just a few questions. first, i assume Don’s on board with this idea (i mean this is one of the things you run by your landlord, no?)

    most of the way it gets reasonable (the last time i paid attention to this stuff) was the tax subsidies. but if it’s not your property, do you still get the subsidy? again, the last time i looked, enough solar power to do anything besides dehydrate a few slices of fruit was not inexpensive. then again, its a mac, so shouldn’t be too bad.

    second, is this an investment you’ll leave with the house when you leave? or will you take it with you?

    third – when you have enough juice that you can power your stereo off it, let me know and we’ll convert all your stuff to DC. and put a switch on the inverter (bad for sound. very bad).


  2. Yeah, I’ll mention it to Don – remember his business is low-consumption energy. He’ll love it. But of course I would get perms to put a few brackets on the roof.

    I don’t know if I can get the subsidy to if it’s not powering the whole home (not sure why feds would care if I own the home).

    By my napkin calculations after an afternoon of running the meter and comparing to our bill, this machine is drawing 1/5 of our home’s power and therefore costing 13.50/month to run. If the solar rig costs $700 it will take 4.2 years to pay for itself even without subsidies. If it draws more hosting customers, it will of course pay for itself much sooner.

    I doubt I’ll have much juice left to run a stereo with…

  3. Running the computer is a wonderful start.
    Let us know how it goes and the juicy details.

    Wouldn’t the generated AC be very clean and
    good for audio equiptment? It has to be a cleaner
    AC signal than what is coming in from the street.

    No line conditioners needed…

  4. whoa!!! $700? everything i saw was more like $7k. what are you looking at getting?


  5. John, inverters come in “modified sine wave” and “sine wave” — the latter should be as clean as what comes out of the wall, but not cleaner. AC still alternates… DC doesn’t which is why it’s great for audio.

    baald, I was quoted $8600 for a full grid-tie system.

    For $700 I would get a 120W panel, an RV battery and an RV inverter, and that’s it. Very minimal, just enought to get the job done. For AC backup I would add a battery charger.

  6. shack/john – yeah, it *could* be cleaner AC, would depend on the converter. There exist what are basically AC>DC>AC converters which are a rectifier which then feeds a very high-quality “inverter” to get extremely pure AC with no switching artifacts for powering audio systems. It’s the switching artifacts that end up problematic even w/ pure sine wave converters (and forget a modified sine wave converter).
    liike i said, depends on the particular one. most people’s street AC is garbage. battery powered music is where its at but not without some potential issues of its own.

    the issue isn’t that it’s AC per se, (and yes there is dirty and clean AC just as there is dirty and clean DC), but how the AC is generated. AFAIK, It will usually involve lots of hi-speed switching devices which generate ugly noise which tends to be hard to filter completly. The high quality dedicated audio ones basically use a synthesized sine wave feeding in essence a heavy duty audio amplifier which amplifies it up to 120 VAC. yep, exactly the same thing as taking the output of your soundblaster and feeding it into an amp, but the input is better and the output won’t blow up (ie, don’t try it at home with your soundblaster and stereo amp)

    one of my imminent projects is a battery powered tube preamp. the problem being of course that i need a B+ of around 180+ volts DC, and would want it dual mono, which means 30 12V batteries in my living room….

    Oh – and the reason that battery power is cool is because rectification itself often involves lots of nasty noise generation. and you have uglies coming in on the AC line. and you often have ground issues. and no matter what, you’ll still have the 60/120 Hz hum to contend with. (and lots of people don’t like the sopund of regulated power supplies which otherwise would take care of some of these issues…)

    if i ever get the project afloat, shack will be the first to hear it so i’m sure he’ll comment on it right here.


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