Reply
 
Thread Tools Search this Thread Display Modes
 
Old 09-20-2018, 08:59 AM   #1
4 Rivet Member
 
1995 30' Excella
Harper Woods , Michigan
Join Date: Aug 2017
Posts: 258
Seasonal tilt adjustment of solar panels

For those who use portable solar panels, this discussion of seasonal tilt angles might be of interest to you to get the most energy from your panels.

https://www.solarpaneltilt.com/

Oh, I just had an idea that is interesting, but probably wouldn't work out in practice. How about repurposing the elevation mechanism of the Winegard VHF/UHF television antenna to optimize the solar panel orientation? I'm doubtful that it could withstand much wind force, and so it would necessary to lower it during windy weather, but then again the same must be considered for the awnings.
__________________

Bob Blarney is offline   Reply With Quote
Old 09-20-2018, 09:24 AM   #2
4 Rivet Member
 
2007 23' Safari SE
2016 23' International
Fernandina Beach , Florida
Join Date: May 2013
Posts: 365
If you don't want to bother changing tilt angles, and will be parked in the same locale most of the year, a good rule of thumb is to tilt the panels at the same angle as the value of your latitude. I have 7.8kW worth of panels on a South Facing roof of my house which coincidentally matches my latitude of 30 degrees. On the Equinoxes, the Sun elevation at Solar Noon is 60 degrees which puts it perpendicular to the panel surface. During the Summer its elevation is much higher and in the winter much lower. But for optimal capture, match the angle of your latitude. Granted, this is for fixed panels facing South. The optimal arrangement would be a tracking system that always faces the Sun.

I would not set an Airstream panel angle up this way simply because of air resistance, but for portable panels, it's a good technique. Any good astronomy site can give you the altitude of the sun at your location at Solar Noon for a particular date. I really like this site too. https://www.esrl.noaa.gov/gmd/grad/solcalc/
__________________

Tomzstream is offline   Reply With Quote
Old 09-20-2018, 09:43 AM   #3
4 Rivet Member
 
1995 30' Excella
Harper Woods , Michigan
Join Date: Aug 2017
Posts: 258
Quote:
Originally Posted by Tomzstream View Post

. Any good astronomy site can give you the altitude of the sun at your location at Solar Noon for a particular date. I really like this site too. https://www.esrl.noaa.gov/gmd/grad/solcalc/
Yes, I've used this site too, to set up sundials. As a matter of fact, I've imagined adapting the analemma from analemnatic sundials to adjust panel orientation. Somewhere in my back pages, I have a spreadsheet that calculates and displays such a sundial for any specific location. One well-known analemnatic sundial is located at Longwood Gardens in Kennett Square PA, which would be nice travel destination.
Bob Blarney is offline   Reply With Quote
Old 09-20-2018, 09:45 AM   #4
Half a Rivet Short
 
2017 30' Classic
Carlisle , Pennsylvania
Join Date: May 2017
Posts: 6,295
Hi

You very much do *not* want to try this with something as lightweight as the antenna arm gizmo. A solar panel has a lot of weight and a lot of "sail area". You will rip it right off the top of the trailer pretty quickly.

Any "tilt" device on a roof mount RV solar needs to have a way of latching down when in motion. That semi in the other lane on a 2 lane road is pushing a lot of air in front of it. If you both are going 60 MHP, your roof likely is getting hit with 120 MHP gusts.

Adequately designed tilt gizmos add weight. Pretty much the last place you want to put weight on an RV is on the roof. Stability wise, it's a bad thing. Weight on the roof and right at the rear is a very bad thing .....

Lots of issues ...

Bob
uncle_bob is offline   Reply With Quote
Old 09-20-2018, 12:20 PM   #5
4 Rivet Member
 
1995 30' Excella
Harper Woods , Michigan
Join Date: Aug 2017
Posts: 258
Quote:
Originally Posted by uncle_bob View Post
Hi

You very much do *not* want to try this with something as lightweight as the antenna arm gizmo. A solar panel has a lot of weight and a lot of "sail area". You will rip it right off the top of the trailer pretty quickly.

Any "tilt" device on a roof mount RV solar needs to have a way of latching down when in motion. That semi in the other lane on a 2 lane road is pushing a lot of air in front of it. If you both are going 60 MHP, your roof likely is getting hit with 120 MHP gusts.

Adequately designed tilt gizmos add weight. Pretty much the last place you want to put weight on an RV is on the roof. Stability wise, it's a bad thing. Weight on the roof and right at the rear is a very bad thing .....

Lots of issues ...

Bob
As I said, it would not likely be practical. It was just 'blue sky' thinking, but that's how innovation eventually occurs.

It would never do for a trailer underway, but for an AS that was set up as a (semi-) permanent installation it might work. But then again it would be easier to set up a ground or pole installation.
Bob Blarney is offline   Reply With Quote
Old 09-20-2018, 01:53 PM   #6
Half a Rivet Short
 
2017 30' Classic
Carlisle , Pennsylvania
Join Date: May 2017
Posts: 6,295
Quote:
Originally Posted by Bob Blarney View Post
As I said, it would not likely be practical. It was just 'blue sky' thinking, but that's how innovation eventually occurs.

It would never do for a trailer underway, but for an AS that was set up as a (semi-) permanent installation it might work. But then again it would be easier to set up a ground or pole installation.
Hi

If the trailer needs to move down the road safely, that puts constraints on what you can add to it. If semipermanent means the trailer never moves then that's different.

There are already manual tilt setups available for trailers and some have them. The typical response after a while is - "I don't bother with it anymore, to much hassle for to little gain".

Bob
uncle_bob is offline   Reply With Quote
Old 09-21-2018, 07:24 AM   #7
4 Rivet Member
 
1995 30' Excella
Harper Woods , Michigan
Join Date: Aug 2017
Posts: 258
Quote:
Originally Posted by uncle_bob View Post
Hi

If the trailer needs to move down the road safely, that puts constraints on what you can add to it. If semipermanent means the trailer never moves then that's different.

There are already manual tilt setups available for trailers and some have them. The typical response after a while is - "I don't bother with it anymore, to much hassle for to little gain".

Bob
The improvement in efficiency is about 4-5%. I waded through a technical engineering paper that states that a maximal seasonal deviation of +/-24d from the equatorial plane at the solstices will improve efficiency from ~71% to 75%, with 100% obtained by using an active tracking mechanism on the mount. So yes, most people probably won't bother.
Bob Blarney is offline   Reply With Quote
Old 09-21-2018, 07:56 AM   #8
Rivet Master
 
dznf0g's Avatar
 
2007 30' Classic
Oswego , Illinois
Join Date: Jul 2010
Posts: 10,051
Images: 5
I fashioned 3 sets of rods for each (2-100watt) panels for my latitude. I use them primarily for when the AS is at home between trips. Each set is set up for the chart angles...1 set for summer, one set for spring and fall, and one set for winter. I have the AM solar feet with the screw handle mounts.

I had to use some geometry to calculate the proper length, due to the AS curved roof.
__________________
-Rich-

"If the women don't find you handsome, they should at least find you handy." - Red Green
dznf0g is online now   Reply With Quote
Old 09-21-2018, 08:17 AM   #9
Rivet Master
 
DaveP's Avatar

 
2004 28' Classic
Monument , Colorado
Join Date: Nov 2015
Posts: 519
Great information. Thanks for posting it!
__________________

__________________
DaveP
2004 Airstream Classic 28 "Willard"
2014 Ford F150 FX4 Ecoboost
DaveP is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Need 8"x29.75" tilt-out Creation window glass for 1999 Safari 27' roscher Windows, Doors, Locks & Vents 1 09-29-2015 03:04 AM
Hehr vs. Full tilt windows. Soyboy Windows & Screens 28 03-17-2012 07:55 AM
Tilt-a-rack . Advice needed. Thanks Octane General Motorhome Topics 9 09-09-2011 03:19 PM
Tilt Switch source? pwhittle Mechanics Corner - Engines, Transmission & More... 2 04-22-2009 07:38 AM
Tilt Mechanism - Lookout Blinds xengineer Upholstery, Blinds, Walls & Interior Finishes 0 09-01-2008 05:09 PM


Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 02:19 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.