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45 W solar panel

  1. Aug 8, 2007 #1
    I recently aquired a 45 Watt solar panel and am now curious about how best to use it. I am currently connecting it to a 60 amp hour battery, on which I would like to store electricity to run small lights and a laptop computer. How can I figure out if this setup will be enough for my small uses?

    The panels are putting out about 20 volts, so I am getting about two amps. I used to use a 6 amp charger (from an AC outlet) and it took about 14 hours to charge the battery. So now I am wondering if my 45 W panel will keep my battery charged at my use rate.

    I have in the past run a few small lights on my battery, and it lasts for months on a charge. I would like to run a telephone and a laptop computer. The computer has a 12 volt socket plug which connects to a port on the computer labelled 19 V DC.

    Any help? Do I need more panels? Can I hook two panels to one battery? If so, should I hook them in parallel or in series?
  2. jcsd
  3. Aug 8, 2007 #2


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    Staff Emeritus
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    Your computer probably uses somewhere in the neighborhood of 50-90W, depending upon the model and what you're doing with it. Your 45W solar panel is only able to collect 45W at noon; at other times of the day, it will produce significantly less power.

    You haven't told us how much you intend to use the laptop, either, but there's no way this single solar panel will be able to power your laptop 24 hours a day. 2-3 hours a day would be more likely.

    - Warren
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