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Thread: Solar security lights - rate of energy flow from solar panel to battery

  1. #1
    Join Date
    Sep 2006
    Location
    Las Cruces, NM
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    2,037

    Solar security lights - rate of energy flow from solar panel to battery

    In a typical solar powered security light, the solar panel charges a battery. When the sun is out, is the battery capable of absorbing energy at the rate the panel generates it ? Or does the panel have over capacity relative to how fast the battery can charge?

    The specific situation that comes to mind involves two security lights, each with its detachable solar panel. if the sun shines on the panels differently during the day (due to the shade of trees etc.) it might make sense to modify the wiring so each panel charges both lights. If one panel has over capacity relative to charging a single light, it could charge both of them when it was in the sun and the other panel was shaded.

  2. #2
    Join Date
    Sep 2007
    Location
    Longview WA
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    Is there a problem with one of the lights not working through the night?

    This may be an over simplified equation to answer a complex solution.

    To charge a battery the source only needs to be at a higher voltage potential than the battery. The charging rate would be determined by how much amperage is produced by the charging source versus the amount of drain sustained by the battery.

    Some home solar systems have circuitry to bypass cells that are in the shade. My neighbors solution to the shade on his panels was to get my permission to cut down the trees shading his roof.

    The technology has changed radically since my days of being involved in electronics. Someone else may have to offer a better answer. My short answer would be to find out from the maker of your units if is possible to connect the two units. They may have a way to set them up in tandem.

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  3. #3
    Join Date
    Mar 2003
    Location
    Monroe, MI
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    11,896
    I bought a relatively expensive solar shed light. There's a small panel and bracket assembly that mounts on the shed and an LED light for inside. Great at first, but now it doesn't work. I suspect the batteries but haven't messed with it yet to figure out why. Our subdivision put commercial grade solar lights on the entrance signs, now we've signed a contract for the local power company to install lights at the entrances because the solar lights failed.

    I wouldn't recommend them at this point. Not sure if the charge circuits are poor or the batteries don't handle the weather.

    That said, I also put a 12x12 solar panel on our shed roof with a 12v charge controller and use that to keep our push mower's electric start battery charged. Its rarely used, but starts every time. That's a gel battery though. I've thought about getting a second gel battery and a 12v LED "bulb" and setting up my own light.


  4. #4
    Join Date
    Sep 2009
    Location
    Medina Ohio
    Posts
    4,515
    round here the county has been installing stop signs with red LED solar lights on them. They are a couple years old now and still work The first one I used to go by is over 3 years old

  5. #5
    Join Date
    Mar 2003
    Location
    Monroe, MI
    Posts
    11,896
    Quote Originally Posted by Jerome Stanek View Post
    round here the county has been installing stop signs with red LED solar lights on them. They are a couple years old now and still work The first one I used to go by is over 3 years old
    I'm guessing that's a different caliber (and order of magnitude more expensive) design than what is available to consumers and light commercial users.


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