Manual tracking

mountainman

Does any one track the sun? I have a 400 watt array and I have been wondering how much difference moving my solar panels would make. So I made a adjustable pole mount with a 100 watt panel. Today being the longest day of the year I did a test. I set 1 100 watt panel at 12° from horizontal  and 180°south. I set the 100 watt panel on the tracker at 12° and 100°sse at 12 o'clock I moved it to 180°. I connected  each panel to a separate dc watt meter. At 1:15 the stationary panel had made 274 watt hours. The one that I moved 1 time made 355 watt hours. Around 23% more. About the same as adding 1 more panel.

706jim

By virtue of how a tracker has to work (a large cantilevered stand) it sounds like a great idea, but has to be substantially strong in order to work. I wonder (and welcome any comments) if it would be better to scrap the tracker and buy more panels.

Dave Angelini

You can virtual track by having a south west and a south east array. There are many strategies and it really is based on what your goal is.
Some want to run cooling on solar as long as possible without using the battery. Some have large water pumping needs and want to run longer hours.

 For offgrid you are off the battery earlier and on it later in the day. Having a couple thousand watts available today at 6 am and using it until 8 pm is a very "solstice" way of getting long hours of power. My web-site has a pix link to some of the trackers I use by Array Technology.

clockmanfran

A few years ago we built a cost effective design of 2 axis Solar Tracker, we even published a small A4 booklet 'How to Make your Own'     ISBN 9780993590313    

     http://www.echorenovate.com/purchase-book---make-a-2kw-solar-tracker.php

We kept it simple, Robust, and cost effective.

Designed to work in open fields with sheep grazing.

Easy maintenance.

Easy to maintain the ground under the Tracker PV panels.

This particular design gives about 35% more output over the year than a static PV array.

No fancy complicated bearings, just a single actuator, and manual operation for the seasons of the year.  Structure actually tested in hurricane conditions, Overall cost of the tracker structure is about $600 includes the actuator and control electronics.

Maximum size of this tracker design is 2Kw,  ie 8 panels, above this and the materials required become prohibitively expensive and the foundation block becomes excessive.

My conclusion.......

Don't bother with Trackers, just add more panels to a static array.

 Yes the static array materials and concrete foundations cost about 1/3rd of a tracker frame.  But the ground under a static array can become un-maintainable if the array is not high enough.

 

   

MichaelK

I built this manual tracker from unistruts, rebar, and fencing pipe.  All welded together with a little 110V Lincoln Electric MIG welder.  I sunk a 8 foot length of 3.5" schedule 40 pipe into concrete, then slipped a 4" pipe over it.  The array is welded onto the 4" pipe.  Its adjustable both east-west, and up-down.  It works!  My arrays have to power my 240VAC well pump, and I find that I'm producing enough watts (2200W) to start the pump at about 8:30 when tracked east.  If they were facing due south, I'd have the watts at 10:00am, so tracking give me and extra 90 minutes.  To be honest though, if I didn't have to supply such a high power load for such long periods of time during the day, the tracker would have been too much effort.  BTW, I'm gearing up to start making my Gen2 v6 array that will be holding four 250watt panels.  Stay tuned!

mountainman

The reason I have interest in tracking Is because I get morning and noon sun but in the afternoon mountains are in the path. I'm thinking of testing aiming a couple panels easterly and a couple to the south. And comparing to all being aimed south.

Dave Angelini

That works fine. It is often called virtual tracking. It does get old moving panels and there is the danger of them being damaged when they are not properly mounted. 

 I disagree with the clockmans conclusion because the he is grid tied and it is a different world when you need some form of tracking offgrid for cooling or powering  well pumps for long hours of the day.

mountainman

@Dave Angelini With virtual tracking can you use 1 30 amp mppt  cc and 2 seperate arrays of 200 watts each. Facing 120° and 180°. Midday  With all 4 facing south I'm getting 23 amps. Roughly what peak amperage should I expect with them pointing in different directions?

Estragon

IMHO, you'd want separate controllers on different facing arrays.

You could check pvwatts.nrel.gov for production at your location at different times of year. The point of facing differently is longer production, not peak though.

MichaelK

Thought I've give a quick update on my system, which is exceeding my expectations.  By carefully orienting the arrays eastward in morning, but being careful not to shade one array with another, my well pump can be started at 8:00am.  After a bit of judicial tree limb pruning, I can now keep the pump running till 5:00pm.  The pump needs about 2000 watts total (including power factor), so I can keep that up for 9 hours a day, with keeping the batteries fully charged and floating.  The arrays need a bit of adjustment before 8am, another adjustment around 10am, another around 2pm, and some more careful monitoring from 4:00 to 5:00, but that gives me an honest 20kwh per day with maybe 10 minutes of attention spread out over the course of the day.