An argument for west and east arrays vs the traditional south array.

softdown · August 13

Battery wear and tear is the chief long term expense of off grid solar.

South facing solar production is strong from ~ 9am to 3pm.

East and west array production is substantial from ~ 7:30am to 5pm. This should, in theory, potentially lower battery wear and tear.

Additional arguments for the west and east arrays:

1) A small amount of work may allow one rack to hold both the west and east arrays. Though two charge controllers will be needed. I hope to post a pic of using one rack for both arrays when it is done.

2) The longer hours may help reduce the impact of summer time air conditioning. Summer time is when the west and east arrays compete more evenly with the south arrays.

3) The east array protects the west array from easterly wind shear. The west array protects the east array in the same way.

4) Some applications will find the west/east more favorable for reducing shade. Others will still favor the south array.

5) If you tend to have cloudy mornings or afternoons the installer may adjust west vs east production accordingly.

* I don’t remember the name of the web site that allows the more exact numbers to be crunched. But I do remember that west and east arrays can be competitive except for substantially more limited production during the winter months.

I’m not saying that west and east panels offer more production. They absolutely do not. But a longer and more evenly balanced production? It should.

BB. · August 13

Can supply more information, including hour by hour 24x365 for spreadsheet.

https://pvwatts.nrel.gov/

Might look at Southeast and Southwest facing arrays with pvwatts.

Lithium batteries work fine on se/sw arrays as well as South facing. can be fully charged in several hours (check manuals and specifications).

For lead acid, need 10+hours on charge to fully recharge (bulk+absorb+reach float) especially important during short winter days.

-Bill

706jim · August 16

I have one array facing southeast and a second facing southwest. All panels in parallel and a single FM80 charge controller. The system works great as built.

Miller_Ranch · August 17

I would suggest the Wattsun HZLA for East and West production.

https://www.wattsun.com/images/datasheets/AccuTrak_HZLA.pdf

softdown · August 18

I have not found a satisfied user of solar trackers. Why don’t the solar farms use them?

softdown · August 18

South facing panels produce more energy - we all know that. I am arguing the benefits of significantly more hours of solid solar production. The voltage level starts climbing earlier - so I can justify heating coffee in the microwave instead of boiling water. The voltage level also stays high for a couple more hours. This has to reduce battery wear and tear.

I used all 40’ of the flat passive solar sunroom for south facing solar production. Works great except for the summer months. I have at least eight fridges and freezers and panels mounted at 45 degrees.

Added 800 watts of ~ 10 degree east facing panels and am quite surprised at their effectiveness. Planning to add 600 watts of ~ 15 degree west panels soon. Then I’ll be back to my usually obnoxious habit of bragging about my solar system. Helps that I live in a solar paradise - 7500’ elevation and dry.

Miller_Ranch · August 18

softdown said:

I have not found a satisfied user of solar trackers. Why don’t the solar farms use them?

Solar farms do use them.

https://www.epelectric.com/energy-tech/energy-portfolio

softdown · August 18

Some of those depicted actually do use trackers. Most do not. A neighbor had a tracker and was dissatisfied. Significant winds often disabled it. This area can be windy.

Miller_Ranch · August 18

The 190 megawatt solar farm in Los Lunas New Mexico uses trackers.

May be an image of text

Image: https://scontent-phx1-1.xx.fbcdn.net/v/t39.30808-6/530846616_1184323823711159_4196097271329320120_n.jpg?_nc_cat=107&ccb=1-7&_nc_sid=127cfc&_nc_ohc=3CbUpeDhvcUQ7kNvwH8fK_r&_nc_oc=AdnJd9RswxK9DLD12Y555_voNhc43tfbHdMSUGPAToAtVTjU6iIaIxg3JG2rk6JhIZpRnHhsniAU3OkphbwXcsFX&_nc_zt=23&_nc_ht=scontent-phx1-1.xx&_nc_gid=kNBiHH-9INdYj52g-EHkCw&oh=00_AfWfLMUhhW3L126YVGwyo4ypK1_RnVHKaUleX5HwKMGBtw&oe=68A92C0B

littleharbor2 · August 18

The solar farms in the Imperial Valley use those same type of rotating axis trackers as depicted in Miller ranches photographs above

softdown · August 18

OK, you guys have prevailed. A few solar farms do use trackers. I wonder if they tend to be lower wind locations. My neighbors complaints seemed wind related and we do have notable winds at times.

Years ago the board consensus was basically “better to buy more panels” as panels have become more affordable. But not everyone has the space.

Miller_Ranch · August 19

A few?
Array technologies has installed 80+ GW globally.
Don't take my word for it.

https://arraytechinc.com/

Passive wind mitigation.

https://player.vimeo.com/video/376938214

I am all for DIY projects. I installed my South facing manual tilt solar mounts myself. I think your efforts would be better rewarded with an East West tracker if your goal is to harvest maximum East and West sun.

Wattsun claims 25% increase over a South facing array.

If your design results in more than 25% gain please let us know.

I live in solar paradise too at 6000' Need some rain.

softdown · August 20

Been here since 2014. Solar tracker isn’t what I want right now. You sound a bit dominant for 49 posts.

An argument for west and east arrays vs the traditional south array.

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