Is a 10A solar controller adequate?

Discussion in 'Tech/Mech General' started by makems, Feb 1, 2012.

  1. makems

    makems Funster Life Member

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    I'm having problemswith batteries at the moment (see separate thread) and in checking various possible causes I have looked closely at the solar controller which appears to be 10A.

    Is this adequate for 2 x 80W solar panels?

    If I remember my schools Physics properly (not a given since it was over 40 years ago!) P=IV or P/V =I

    So 160w/12V=13.333A

    If i'm right and the controller is under-rated what effect will it have?

    Mike
     
  2. pappajohn

    pappajohn Funster Life Member

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    technically the controller is under rated but the 13 amps is a dream....

    in the real world the output may be around 10amps, if the panels are flat on the roof, in good sunshine.
     
  3. dave newell lvs

    dave newell lvs Trader-Vehicle Services

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    As it happens I rigged up two 80 watt panels this afternoon to test them, with them directly facing the sun they were giving a total combined current of 10.4 amps. Laid flat on the ground they gave 3.5 amps. Flat on your roof in July in Spain they could easily exceed 10 amps so yes you need a bigger reg.

    D.
     
  4. makems

    makems Funster Life Member

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    Thanks for the replies.
    They are flat on my roof so at this time of year even in Algarve they probably won't exceed 10A.

    But what impact will there be on my system should the current exceed 10A?

    I want to wait to get home (April) and get the robbing b*stard who installed them to replace with the correct spec. But I don;t want to risk wrecking something in the meantime and will replace out here if the potential consequences justify it.
    Mike
     
  5. pappajohn

    pappajohn Funster Life Member

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    the controller will regulate the output current to a maximum of 10amps...exceed this and the controller must still get rid of those extra amps.......in the form of heat.

    wont do the controller much good in the long, or possible short, run.

    if you buy a 20amp controller you have spare capacity for another panel if you decide later to buy one.
     
  6. Techno

    Techno Funster Life Member

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  7. makems

    makems Funster Life Member

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    Thanks for the replies.
    I will get a new controller butleave til I get back to Blighty in April as the risk of over-cooking the present one is probably low given the time of year and the fact the panels are flaton the roof.
    I'll alsolook at a sysytem which can raise the panels to face the sun more directly. Loads of vans over here in Portugal seem to have this sort of arrangement.
    Mike
     
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