MEDIA WORKERS AND TV RESEARCHERS - Please seek permission before posting on this site or approaching individuals found here by phone or email - write to the Editor - mail to nick@off-grid.net


Home Forums Technical Discussion Do soalr panels have to be “aimed”?

This topic contains 11 replies, has 7 voices, and was last updated by  elnav 7 years ago.

Viewing 12 posts - 1 through 12 (of 12 total)
  • Author
    Posts
  • #36622

    rbd1967
    Member

    I am new to this, and was wondering if solar panels should be aimed to where they will get the most direct sunlight. What angle should panels be set? Any help is appreciated.

    #40664

    tlagrone
    Member

    http://hubpages.com/hub/Solar-Angle-Calculators

    No shade is more important than exact angle.

    #40666

    revinger
    Participant

    In addition to setting the angle as mentioned in the previous post they should be ‘typically’ pointed straight south for those in the northern hemisphere. There are exceptions to this though based on what obstructions are around you.

    automated trackers are available but unless one has a huge array the cost is usually not worth it. The time of year where trackers would benefit the most (winter) is also the time of year when they will least help.

    bob

    somewhere in illinois

    #40481

    elnav in hixon
    Participant

    Forget the complicated stuff like compass or latitude scale. the simplest tool to determine the right angle is a simple block of wood or plastic. Place a shadow pin in it by drilling a hole that is a tight fit for a short lenght of arc welding rod or even a piece of straight coat hanger. Drill the hole with a drill press so the shadow pin is exactly perpendicular to block surface. Place block on solar panel and adjust panel angle and direction so there is no shadow of the pin showing. the pin is now pointing directly at sun. As soon as the panel is angled off a shadow appears. You can either manually adjust the panel every 15 minutes or pick an average at local high noon then lock in the panel for the season. It has been mentioned that summer and winter angles will vary. This shadow pin tool also helps here. I tested it out while measuring the solar panel output. adjusting every 15 minutes makea big difference.

    For permanent attachment place the block and pin along the frame do not let block obscure panel because it reduces output voltage.

    #40680

    elnav in hixon
    Participant

    Forget the complicated stuff like compass or latitude scale. the simplest tool to determine the right angle is a simple block of wood or plastic. Place a shadow pin in it by drilling a hole that is a tight fit for a short lenght of arc welding rod or even a piece of straight coat hanger. Drill the hole with a drill press so the shadow pin is exactly perpendicular to block surface. Place block on solar panel and adjust panel angle and direction so there is no shadow of the pin showing. the pin is now pointing directly at sun. As soon as the panel is angled off a shadow appears. You can either manually adjust the panel every 15 minutes or pick an average at local high noon then lock in the panel for the season. It has been mentioned that summer and winter angles will vary. This shadow pin tool also helps here. I tested it out while measuring the solar panel output. adjusting every 15 minutes makea big difference.

    For permanent attachment place the block and pin along the frame do not let block obscure panel because it reduces output voltage.

    #40811

    elnav
    Member

    evinger wrote:

    The time of year where trackers would benefit the most (winter) is also the time of year when they will least help.

    bob

    somewhere in illinois

    REPLY

    That all depends!! I thought as bob did as well but I have been taking note of sunrise and sunset positions for a year now and find that in summer the sun rises in the north east BEHIND a south facing solar panel and also sets behind it to the northwest. There are several hours between when the sun is due east or west of a south facing solar panel and either sunrise or sunset. In practical terms ther is very little difference in hours winter or summer that the sunlight strikes the panel ant a usable angle. There is a difference in how high in the sky the sun gets at noon. The further north or south of the equator you are located the greater this effect becomes.

    Trackers can become very expensive real quick when the solar panel array is large enough and weighs more than a few pounds. There is an additional consideration. Winds can be strong enough to rip the solar panels away from their mountings unless they are very secure. By their nature a tracking array is more fragile than a fixed post frame support.

    People should be aware of how this is related to their latitude

    #40851

    revinger
    Participant

    Yes. I am at about 40 degrees north and even at this latitude I notice the pronounced northeast sunrise, northwest sunset. I am not so far north though that I losing all that much.

    I have really good siting. In the summer time I have nearly 12 hours solar exposure but the leading and trailing hour or two is pretty wild angle.

    Trackers are just not an option for me though. Lots of surface error and as elnav notes it gets complicated with the larger trackers. Before I added the ‘big pole’ I would hand track some of my smaller panels but now with 2200 watts of PV summer time I usually have more power than what I need anyway.

    The big pole is a 6″ sched 40 pipe with 6 KD205 panels. As I remember shipping weights including the rack and panels there is probably 500 watts sitting on top of the pole. It takes 2 just to adjust the seasonal angle.

    I actually left all my panels at equinox settings instead of bringing them back to summer. Did that partly due to getting some 1.5″ (nearly golf ball sized) hail. No damage but I liked the idea of the slightly shallower angle to hopefully help deflect hail that size(if it happens again).

    WIth the MPPT controllers I am still getting 10-12 kwh on a full sun day in the summer.

    bob

    marshall, IL

    #40852

    moguitar
    Participant

    My original system was 8-Astropower glass panels on a full tracking Wattsun pole mount to make up for the fact I needed 11 of the same panels if fixed mounted at the average seasonal angle south. I had to buy a Manual Control to defeat the pancaking during a hail storm or heavy snow.

    Later I expanded with Unisolar unbreakaable on a seasonal adusting fixed south mount. I found that just using the average was fine, and I was getting 90% power with the sun at a 45* angle to the panels. I have since added 4 more on much cheaper home made mounts out of aluminum L metal, at the fixed average angle.

    It is the shiny smooth glass panels that have high reflectivity. When I had to fix mine to send in the sun seeker for repair, they only picked up 10% power at a 45* sun angle from the panel face. I never had to worry about the hail storms with the Unisolar. If I was going to be gone in hail season, I would have to fix the tracking array at a steep angle south, reducing power input while we were away. We also had to do it in snow season so the sun seeker would not get blinded by heavy snow, and THEN we had to leave the inverter on to run the house heater. This was taking a risk on auto shut down if it was very cold and cloudy, and the risk of frozen pipes.

    Now there are other rough surface, unbreakable panel companies. Unisolar even has flex panels that have glue backing to go right on metal roofing. Much more wind proof, and you can walk on them. Shiny glass panels really need the tracking. Tornado Alley needs the glue on to a really solid metal roofing system, or something equally strong and unbreakable.

    With fixed mounting, you have to figure in off average sun angle losses for the particular panel type.

    #40864

    houstongrid
    Participant

    There seems to be some confusion regarding panel tracking. I live at lat’ 54 degrees. During summer, If I was not tracking, I would lose almost 6 hrs of sunlight at Solstice, tapering to about 2 hrs at Equinox.(september) and, of course panels do not put much out until the sun angle on them is within about 75 degrees of center, increasing to maximum, at 90 degs, (high noon). There is very little need to track here after about the end of October, although I do because it takes very little to run the tracker and there still is a few amps that can be gained by tracking.Even on the equator, you will loose the low angle radiation, east and west if you do not track. It is easy to prove this for yourself, if you wire a reasonable load resistor, something that will draw/dissipate the rated output of your panels, with an amp meter is series, you will see that the panels will have very little output until the sun reaches 15 to 20 degrees above the horizon of your panels, and, it will increase as the angle reaches 90 degrees. Now, The next morning, as soon as the sun is up, tilt your panels into the sun and watch your amp meter. This is assuming the “tilt” angle is at 90 degrees as well. Hope this helps. Ric,,,,

    #40869

    elnav
    Member

    Houstonongrid are you by chance located on Hw 16 a bit west and north of Burns Lake? Have off grid relatives up in that area on Babine Lake.

    Elnav

    #40872

    houstongrid
    Participant

    Hi Elnav, no, I am south of Houston, Babine lake is N/e of me about 75 Km. “73”, Ric

    #40874

    elnav
    Member

    Hi Ric so you are in the neighbourhood Send me an email [2elnav(at) netbistro.com] Sounds like we have a few things in common. How’s your forest fire situation? We got cut off for about 4 hours today and the smoke from the Quesnel fire is so thick we can’t breathe outdoors. Other than that no problems!

Viewing 12 posts - 1 through 12 (of 12 total)

You must be logged in to reply to this topic.