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Itinerant1's avatar
Itinerant1
Explorer
Oct 18, 2017

Solar panel shading

With 1,280 watts of solar I don't worry to much about getting enough solar. This time of the year with the days getting shorter and we're in the national forest boondocking catching light shadows from some pines I would expect some drop off in amps going to the battery (can see it on the display).
Yesterday morning while I was walking the dog I was checking the shadowing on the panels from the trees from the hill behind the 5th wheel and noticed that the crank up antenna was casting a good shadow on 2 panels (each in a different series string). This morning at 10am I remebered about the antenna shadow and before cranking it down there was 25-26amp reading, after lowering it down 36-37amp. That's a pretty fair boost just lowering the antenna, during the day seeing we're not watching it anyways. I'll have to pay attention to the tv antenna during the winter so not I'm losing any possible power.;) We know about shadowing on the panels but seeing it yourself is a little eye opener.

35 Replies

  • Almot's avatar
    Almot
    Explorer III
    Itinerant1 wrote:
    ... A .5kwh pick up is nice and certainly helps keeping the batteries charged.

    ... or it helps you staying fit, through cranking exercise :)

    When batteries are floating and controller goes to rest before sunset, - doesn't matter how much more energy there is in the sky. In your case it sounds like they were not floating yet or some loads were running often.
  • Easy to take out more real estate than actually covered.
    Certainly did not lose everything.
  • Almot's avatar
    Almot
    Explorer III
    30% drop, and antenna shade probably didn't cover 28-29 sq.ft. (30% of 1,280W).

    When I posted about this oddity in series panels few years ago, nobody believed me. People were talking about magical powers of bypass diodes, sheesh...
  • I never paid attention to the antenna but will for now on. I've been in this location for 12 days now with the past 3 days having 2.7, 2.8, 2.8kwh harvested. Today with the same conditions as the past days and harvested 3.3 harvested. A .5kwh pick up is nice and certainly helps keeping the batteries charged.
  • Good catch. Just orient the RV different to eliminate the antenna shadow.

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