Solar Generator for Bedroom Appliances

Discussion in 'The Projects Forum' started by 42Wired, May 16, 2009.

  1. 42Wired

    Thread Starter New Member

    May 16, 2009
    I’m planning on building a solar generator to power my TV and HTPC to cut down on my electric bill. I’ve looked at 12 V deep-cycle batteries, and the one with the most capacity that I’ve found so far is 305 Ah. My TV and HTPC run at roughly 1000 W combined, so that gives me about three and a half hours of usage. (Do I need to do some sort of RMS conversion for AC voltage?)

    I don’t think 3.5 hours is enough time. I want to be able to run both simultaneously for up to 10 hours without having to plug into a wall outlet. This has led me to the conclusion that I will need more than one battery. I am a computer engineer, but my experience has been mostly software. I know I should put the batteries in parallel to get more capacity out of them, but I just want to make there are no caveats to connecting big batteries this way to AC appliances (through an inverter, of course).

    Below is my planned parts list.
    - 40 W Solar Panel
    - Batteries
    - Inverter
    - Insulated Wire
    - Volt Meter
    - Battery Box (Probably a cooler or something)

    Is there anything else I need? I think a surge protector would be nice, but I could probably just use a power strip with one built in.
  2. Audioguru


    Dec 20, 2007
    For a little 40W solar panel to charge a 1000W battery it will take 25 hours of noon sunlight. That is almost two weeks without any clouds.

    A 400W solar panel will charge your battery in one sunny day but it will be very expensive.
  3. 42Wired

    Thread Starter New Member

    May 16, 2009
    Ooh, right. I scaled up the battery capacity without thinking about that.

    Looking at 400 W models, they are VERY expensive. And they price the lower-wattage models just so if you buy enough to equal 400W, it costs the same.

    If I used a 400 W panel, it would take about 32 years for the project to pay for itself. I guess I overestimated energy rates. I looked up the rates for my area online. It was partly a novelty, anyway.

    If anyone has any alternative suggestions that don't require me pedaling my butt off on a bike, I'd be open to them.
    Last edited: May 16, 2009
  4. HarveyH42

    Active Member

    Jul 22, 2007
    You might be able to get by with a smaller system, unless you live in Canada. :) Conservation is the key to saving money, and battery power. You just need to learn some new habits, which will come easy, since you want to get the most out of your stored energy. Don't think many people spend 10 hours/day in the bedroom, just not health. Learn to turn off the computer, TV, and lights when not in use. Spend a little time outside the house (cleaning solar panels). Maybe use the computer, or the TV, but not both at the same time. Once you get the hang of it, and apply the same habits to your stuff plugged in, you'll start saving even more on your electric bill.

    Figure on at least 200 watts to be barely useful, might get by depending on where you live, but expect to run out of power.
  5. 42Wired

    Thread Starter New Member

    May 16, 2009
    It isn't that my electric bill is out of control. I just wanted a project I could work on that will be useful that could save me a little bit of money. I don't really watch that much TV, but I wanted enough power stored just so I could if I ever wanted to.

    I found a battery that is rated for 225Ah and an 80W solar panel. This would provide a little over 2 hours of use, but take 34 hours to charge...

    I might just make a small one to charge portable electronics or something. Any other good ideas on what a small one could power?
  6. thingmaker3

    Retired Moderator

    May 16, 2005
    You don't happen to have a year-round stream on your property, do you?
  7. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    :p that would be wonderful