Angle of the dangle

oldmakooldmako Registered Users Posts: 9 ✭✭
edited October 2017 in Solar Beginners Corner #1
Greetings again from uber noobie and neophyte wannabe.

Installing a 100 W  (26"X40") panel on the T-Top on my boat.  I will ONLY use this to keep my two deep cycle group 31 batts topped off and nothing more.   

Q.  IF I just mount it flat (easy install and ideal for when boat is in use - choppy water etc) will I get reasonable performance from this panel, or is this a complete bust? 

1.  The boat is on its trailer 85 percent of the time.  I'm lucky to get 8 days per month in summer, half that in spring and fall.   Maybe 2-3 to zero in winter when / if the humpbacks show up.

2.  Due to my parking spot, and the fact that the boat is tilted slightly bow up while on the trailer, my panel will likely tilt be a few degrees away from horizontal, and angled AWAY from the sun.  The bow of the boat is pointed south.

3.  According to the solar calculator I used  (, the following degrees of tilt are recommended.   

Winter - 30
Spring / Fall - 53
Summer - 76

Since I am not powering any appliances I don't require maximum performance from the panel.  But, since I am going through the trouble I am kicking around a pivoting mount that will allow me to change the inclination of the panel, IF required to get the voltage I need to maintain my batteries.   I figure that it would be fairly simple to design an articulating 3 position mount -

1- Stowed flat and secured for when the boat is in use.
2. A summer setting.
3. A second setting for Fall - Winter - Spring.  I'd just split the difference between 30 and 53 degrees.

Since the boat clangs and bangs when in use, I'm trying to come up with a mount that is both secure, yet somewhat giving and flexible to minimize the shock to the panel.  Its covered with tempered glass and has thin aluminum channel for its 4 rails.

I guess the Q is, will this panel perform adequately when relatively flat, or do I NEED to make a proper mount to get all perpendicular and what not??

Clueless in Virginia Beach.


  • EstragonEstragon Registered Users Posts: 1,819 ✭✭✭✭
    You might want to check out

    It lets you put in various panel angles for your location to get a sense of what to expect.   Generally, having the panel flat isn't too bad in the spring/summer in higher latitudes.  What you lose in peak production is offset to some extent by extended morning/evening production. 

    Late fall and winter can be a problem though.  The weak sun and low sun angle will cut potential quite a bit.  Also, if the boat is near trees that shed leaves, a leaf or two sitting on the panel can cut output to near nothing (possibly less that zero), as will snow if that's a factor in your area.  If these factors might be an issue for you, maybe consider rigging up a way of hanging the panel vertically over the winter, and put it on the t-top for other seasons? 

    If your weather is cool over the winter, you may be better off disconnecting the batteries if you can't rig up a winter mount.  Battery self-discharge diminishes with lower temps, so leaving them for 3-4 months may be better than risking shaded panels and controller tare losses draining the batteries instead of floating them.
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mcgivormcgivor Registered Users Posts: 1,405 ✭✭✭✭
    The idea of a pivot is a good idea, a hinge on the bow end, latch at stern end with a drop down leg, to give some angle. Another idea which jostling popped to mind is using casement window hinges would have to be weather/salt resistant, just an idea.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • oldmakooldmako Registered Users Posts: 9 ✭✭
    edited October 2017 #4
    There will be pine needles, but only a few, from one tree.  With the panel is inclined 45 degrees I don't think that they'll be an issue for me.  Snow is a rarity here, although it has snowed more in the last 3 years then it has in the previous 25.  I will be surprised if the unit is ineffective during winter, provided I can keep it clean.  If so, I'll disconnect and or give them an occasional AC recharge.   

    Casement hinges.  Genius!  And, they're available in stainless.  Perfect.  Thanks.
  • mcgivormcgivor Registered Users Posts: 1,405 ✭✭✭✭
    Casement hinges.  Genius!  And, they're available in stainless.  Perfect.  Thanks.

    You're welcome.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

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