12v from wall wart vs 12v from battery

Discussion in 'The Projects Forum' started by cubbyboy57, Nov 24, 2012.

  1. cubbyboy57

    Thread Starter New Member

    Nov 24, 2012
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    I am planning a small off grid solar install and would like to power my network equipment (router/switches/cable modem) off the battery. I am trying to figure out if they can just be wired to the battery as they all are powered by 12v wall warts or do I need to have some sort of regulator?

    Any help would be appreciated.
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,156
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    No concerns, IMHO, on using the battery directly. Typical wall warts deliver well over 12V, maybe 16V or more at light or no load.

    There is one issue - if the battery disconnects or fails and your devices see the full panel voltage. As long as the battery is connected, it will limit the voltage.
     
  3. cubbyboy57

    Thread Starter New Member

    Nov 24, 2012
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    0
    I am trying to set up the system like an RV with a 12v "side" of lighting and light duty appliances and a 120v "side" with larger appliances through an inverter. Seemed wasteful to convert dc to ac and back to dc, but didn't know if these types of electronics are sensitive to voltage changes (11.5v - 14v). Thanks for the quick reply.
     
  4. wayneh

    Expert

    Sep 9, 2010
    12,156
    3,063
    Generally they are not, if they are using a traditional wall wart. If you see a regulated SMPS (smaller, lighter, efficient), it would be worth checking the typical operating voltage with a meter. Even so, I can't think of any such thing I've ever seen that would be damaged by 14V but is fine at 12V.
     
  5. #12

    Expert

    Nov 30, 2010
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    Yep. Solar cells don't have the nasty noise spikes that car alternators cause. I believe this will work.
     
  6. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    Wall warts are not created equal. Some are just a transformer and rectifier so they have no regulation, some have built in switcher supplies which are very well regulated. You can get them on ebay for $5.
     
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