Automatic or manual method to tilt solar array

solarguy
solarguy Registered Users Posts: 4
in General Solar Power Topics #1
Hi,

Am new to this site, but have a question. Does anyone know of a weathproof jacking mechanism (no not a tracking system in the traditional sense), a way electronically or mechanically to adjust the tilt of my solar array without having to climb up on my roof at the cottage and physically lift the panel array by hand to change the tilt from say 22 degrees to 64 degrees. I am just adjusting in one dimension not tracking in a two dimensional sense. Just looking for a way to adjust the angle of the array (3 235 watt panels) without having to climb the roof? Any ideas or suggestions, thanks for your help (in advance).
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Automatic or manual method to tilt solar array

    Welcome to the forum.

    I must say I've thought about this quite a bit for the same reason: the Summer/Winter shift at 52 Lat is quite significant. I have not found any commercially available device specifically for this. I have thought of multiple schemes for achieving the effect (all involving electrically driven screw-jacks or scissor jacks and micro switches to control limits). The expense for something that would get used 2X, maybe 4X a year didn't seem worthwhile. Adding in the potential need to climb up there anyway and fix it when it didn't work when needed ...

    In the end I opted for setting them at the Spring/Fall angle as a compromise. The long Summer days makes the power adequate then, and the place isn't used in Winter so there's still enough to keep the batteries up even though the angle is less than ideal.

    Of course I'm a lazy old man so what you choose to do may differ. :D
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #3
    Re: Automatic or manual method to tilt solar array
    solarguy wrote: »
    Hi,

    Am new to this site, but have a question. Does anyone know of a weathproof jacking mechanism (no not a tracking system in the traditional sense), a way electronically or mechanically to adjust the tilt of my solar array without having to climb up on my roof at the cottage and physically lift the panel array by hand to change the tilt from say 22 degrees to 64 degrees. I am just adjusting in one dimension not tracking in a two dimensional sense. Just looking for a way to adjust the angle of the array (3 235 watt panels) without having to climb the roof? Any ideas or suggestions, thanks for your help (in advance).

    Not sure whether it would work for the weight and wind loads you would be experiencing, but there have been mechanisms for opening large arrays of windows in commercial buildings which use either a hand crank shaft or an endless chain turning a wheel along with gearing to rotate a crank arm, which could then be used to move one end of the array with the other end pivoted. I think this would be a lot more stable than trying to use some sort of center mount as you would for a ground-based array.

    You could probably get a used mechanism from a scrapped roll-up door that could be adapted. (But do not get involved with the torsion spring unless you know what you are doing! Those things are dangerous!)
    SMA SB 3000, old BP panels.
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  • solarix
    solarix Solar Expert Posts: 713 ✭✭
    #4
    Re: Automatic or manual method to tilt solar array

    I too have thought about how to capitalize on the significant benefit of retilting the array a few times per year. Even tried to rig up a scissor-jack arrangement. What I learned was: that there is a sizable weight involved especially if you factor in dynamic wind loads. A low-cost gizmo is not going to do it. Also found that the gains were not that great. My array is fixed at 15 degrees and I only saw appreciable gains when adjusting the tilt way up for the winter. Of course that would mean spreading my array rows way out - needing more space. Bottom line is that the cost of the tilt mechanism is around four times the value of the extra power. Plus the risk of failures, etc. Lower cost PV modules kill this idea just like they are doing in the standard tracking systems.
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  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    #5
    Re: Automatic or manual method to tilt solar array
    solarguy wrote: »
    Hi,

    Am new to this site, but have a question. Does anyone know of a weathproof jacking mechanism (no not a tracking system in the traditional sense), a way electronically or mechanically to adjust the tilt of my solar array without having to climb up on my roof at the cottage and physically lift the panel array by hand to change the tilt from say 22 degrees to 64 degrees. I am just adjusting in one dimension not tracking in a two dimensional sense. Just looking for a way to adjust the angle of the array (3 235 watt panels) without having to climb the roof? Any ideas or suggestions, thanks for your help (in advance).
    I do have a suggestion. Before you expend any effort or money on this (and if you haven't already done this), run a few simulations in PVWatts to see if doing this is worth it to you. Use the monthly data from the months you propose tilting the array at different angles and total it up for the year and compare it with different stationary year long tilts and see what you get. Also consider wind loading; a 64 degree tilt will be a sail. Another thing: that's a tilt differential of 42 degrees; that sounds like too much to me, but run those simulations.
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  • Organic Farmer
    Organic Farmer Solar Expert Posts: 128 ✭✭
    #6
    Re: Automatic or manual method to tilt solar array

    My idea is to mount a row of 6x8 posts in a straight line dew East-West. Across the top of them mounting 1" pipe-black. Then install the panels on that black-pipe using Omega-shape 'strap-clamp's.

    http://www.plumbingsupply.com/images/2hole-galvanized-pipe-strap-clamp.jpg

    In such a manner that the solar panels could 'pinwheel' [assuming there were no wiring or other attachments]

    Then mount hinges on the ends of the panels, 2x4 arms going back to the mounting post, an angle-iron bracket, and cotter-pin to lock the adjustment arm in position.

    In this manner, I plan to be able to make minor adjustment weekly to the angle of all panels.

    Sorry I have no photos.

    I got it all up this fall, [posts, pipe, panels, adjustment arms] but had not gotten proper hurricane tie-down guy-wires in place yet; when we had a gale wind and my entire array blew down. All posts were 6x8s mounted in concrete filled sonotubes, and they broke-off inside the sonotubes at grade.

    I will try again next season. :)
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  • Logan5
    Logan5 Solar Expert Posts: 32 ✭
    #7
    Re: Automatic or manual method to tilt solar array

    an old TV rotor and control box? I have thought of also using a linear actuator off of an old "Big Ugly Dish" ="BUD" some of them go up 24 inch I think. if I ever engineer my panel mount to allow movement, I will just go ahead and buy a tracking system and use a linear actuator since I would mount the panels at the center of the short ends long ways north/south. so as to minimize the actual movement needed to track the sun during the highest potential sun hours. I would prefer to make elevation adjustments manually or with a separate control module. I have also thought of a polar mount straight off of an old "BUD" as I have seen many do this as well. if the Damn SUN would just stay in one place all trouble solved. lol
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #8
    Re: Automatic or manual method to tilt solar array
    Logan5 wrote: »
    if the Damn SUN would just stay in one place all trouble solved. lol


    We all know that it is mostly the earth that is moving. :-)

    This is fine for a single row of panels, just remember that for a roof mount or for multiple ground mount rows, you need to allow more spacing between rows so that there is no shading when they are at maximum tilt. For a roof mount with limited space, you either end up having to lift the entire mult-row array above your roof peak or you lose just as much be dead space between the rows in summer as you gain in the winter.
    What is more important to you in each case, number of panels or the space they occupy?
    SMA SB 3000, old BP panels.
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  • H2SO4_guy
    H2SO4_guy Solar Expert Posts: 213 ✭✭✭
    #9
    Re: Automatic or manual method to tilt solar array

    My solution was to make the roof at a 2 / 12 angle so it would be gentle to work on. Then I went to the scrap yard and purchased steel at $.30 per pound. The upright pipes are 4" around and 1/4" thick steel while the cross pipe is 3" around and 3/16" thick. The panels are on a closed end type of generic unistrut (Solid back, no holes) doubled up for strength. All of the nuts and bolts are stainless. It is easy for 2 people to change the angle and the weight is balanced so even one person could change angles. The legs were made from the unistrut stuff too. Think teeter todder. So far they are working out very well and quite strong. We also made the roof out of 2x10's on 16" centers with cutouts for 2x10 to run flat along the length of the roof. It is very strong and quite solid under your feet. The old siding tin was used for the roof and elastomeric sealer was used to seal it. Works great, just want more panels!!! Is there ever enough? The goal is to have A/C this summer. This is an old barn and where it is there are no building codes, no zoning, and most importantly, no code Nazi's.

    Skip
    12K asst panels charging through Midnite Classic 150's, powering Exeltechs and Outback VFX-3648 inverter at 12 and 48 volts.  2080 AH @ 48 VDC of Panasonic Stationary batteries (2 strings of 1040 AH each) purchased for slightly over scrap, installed August 2013.  Outback PSX-240X for 220 volt duties.  No genny usage since 2014. 
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  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    #10
    Re: Automatic or manual method to tilt solar array
    H2SO4_guy wrote: »
    My solution was to make the roof at a 2 / 12 angle so it would be gentle to get up to. Then I went to the scrap yard and purchased steel at $.30 per pound. The upright pipes are 4" around and 1/4" thick steel while the cross pipe is 3" around and 3/16" thick. The panels are on a closed end type of generic unistrut (Solid back, no holes) doubled up for strength. All of the nuts and bolts are stainless. It is easy for 2 people to change the angle and the weight is balanced so even one person could change angles. The legs were made from the unistrut stuff too. Think teeter todder. So far they are working out very well and quite strong. We also made the roof out of 2x10's on 16" centers with cutouts for 2x10 to run flat along the length of the roof. It is very strong and quite solid under your feet. The old siding tin was used for the roof and elastomeric sealer was used to seal it. Works great, just want more panels!!! Is there ever enough? The goal is to have A/C this summer. This is an old barn and where it is there are no building codes, no zoning, and most importantly, no code Nazi's.

    Skip
    What wind zone are you in?
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  • H2SO4_guy
    H2SO4_guy Solar Expert Posts: 213 ✭✭✭
    #11
    Re: Automatic or manual method to tilt solar array

    Wind Zone 4, in the middle of the country.
    12K asst panels charging through Midnite Classic 150's, powering Exeltechs and Outback VFX-3648 inverter at 12 and 48 volts.  2080 AH @ 48 VDC of Panasonic Stationary batteries (2 strings of 1040 AH each) purchased for slightly over scrap, installed August 2013.  Outback PSX-240X for 220 volt duties.  No genny usage since 2014. 
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  • solarguy
    solarguy Registered Users Posts: 4
    #12
    Re: Automatic or manual method to tilt solar array
    Cariboocoot wrote: »
    Welcome to the forum.

    I must say I've thought about this quite a bit for the same reason: the Summer/Winter shift at 52 Lat is quite significant. I have not found any commercially available device specifically for this. I have thought of multiple schemes for achieving the effect (all involving electrically driven screw-jacks or scissor jacks and micro switches to control limits). The expense for something that would get used 2X, maybe 4X a year didn't seem worthwhile. Adding in the potential need to climb up there anyway and fix it when it didn't work when needed ...

    In the end I opted for setting them at the Spring/Fall angle as a compromise. The long Summer days makes the power adequate then, and the place isn't used in Winter so there's still enough to keep the batteries up even though the angle is less than ideal.

    Of course I'm a lazy old man so what you choose to do may differ. :D

    Thanks for your response. I understand that you are not at your cottage in the winter and neither are we (very much), but when you say in winter "there's still enough to keep the batteries up" are you saying they get to 100% of capacity in the winter or do you know what SOC they maintain??? Just wondering because, I was thinking it was important to, if anything, maintain a winter tilt so the batteries would stay as fully charged as possible (since I can't always access them monthly to "equalize" them) and I don't want them to deteriorate before spring. Do you worry about that? Maybe I am worried about nothing....

    Giles
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #13
    Re: Automatic or manual method to tilt solar array

    Over Winter there are no loads on my system: the inverter is disconnected entirely. As such the only power requirements from the charging system is to maintain the batteries against the self-discharge rate, which is extremely low. Ironically the cold temps work in your favour here as they further slow the self-discharge.

    When I show up in Spring, the batteries are full and Floating. You do not need the maximum charge rate/Watt hours to achieve this.
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  • solarguy
    solarguy Registered Users Posts: 4
    #14
    Re: Automatic or manual method to tilt solar array

    We have a cottage in New Brunswick, I know your place is in BC somewhere. Could I ask for your email address as I have some questions about your set-up that is out of bounds of the topic of solar array tilt. Thanks.

    Giles
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