Solar tracking

[Praveen]

What are your experiences with solar tracking? I have 2KW solar installation. If I can do solar tracking(2 axis) that will help me generate 2.3 KWH more a day.

My biggest concerns are,

* I have to design the mechanical structure.

* Stability from wind.

I like this system below(from youtube). However, I don't see this available for sale in my place.

 

https://www.youtube.com/watch?v=SSrnkKdo-0s

 

[DeepBass9]

It is cheaper to buy an extra solar panel and achieve the same result, without the mechanical complexity IMHO.

[Guest]

Plus one on that. More complexity, more costs. More panels are cheaper.

[___]

5 minutes ago, DeepBass9 said:

It is cheaper to buy an extra solar panel and achieve the same result, without the mechanical complexity IMHO.

Might need a bit more than 1... you'll need around 500W extra, which is two panels. Still much cheaper :-)

[Praveen]

10 minutes ago, plonkster said:

Might need a bit more than 1... you'll need around 500W extra, which is two panels. Still much cheaper :-)

Agree. I was thinking about that as well  Yeah, it makes sense to add more panels than investing in the complexities.

[___]

IMHO PV modules are becoming so cheap it makes sense to add multiple strings pointing in different directions so you get a flatter peak at noon but a longer solar day. Will have to see how that pans out, I'm about to point a bunch of panels North-West to see how much afternoon sun there is to be had.

[Mark]

I've done that with a small test string facing WNW (480W @ 45deg tilt) and get 7 amps @ 17:00.  There is power to be had!!

[___]

1 minute ago, Mark said:

I've done that with a small test string facing NNW (480W) and get 7 amps @ 17:00.  There is power to be had!!

If it all works out, I'll have 600W pointing North East, 600W pointing North, and 640W pointing North West. There will of course be some overlap too. The idea is to get a 1kw peak for as long as possible. Sure, that doesn't sound like much, but it means I don't have to put the midday peak into a battery and take it out again later, and with my ESS setup I'm really only after baseline+common appliances. The objective is to cut about 30% of overall consumption (for now) because that's the bit that costs more than R2/kwh from CoCT.

Of course, come winter time, a new itch will begin, because one thing that has certainly exacerbated is the ratio of summer to winter consumption. Presently about 3:1 :-)

[Mark]

The trick is the multiple MPPT's (unless your inverter already has 2+).  I have set my float voltages differently to avoid arguing around mid day.

[Riaanh]

Or simply procure one of THESE

[___]

1 minute ago, Mark said:

The trick is the multiple MPPT's (unless your inverter already has 2+).  I have set my float voltages differently to avoid arguing around mid day.

I plan on using the repaired Microcare unit for the second array, but I'm possibly going to move it over to a Victron BlueSolar unit at some point. With ESS, the MPPT is voltage-controlled from the CCGX/Multi, so that bit is sorted. I'm not yet sure how the Microcare is going to do in this setup, we'll have to see :-)

[___]

1 minute ago, Riaanh said:

Or simply procure one of THESE

Wahaha! The smartflower. Wish I could afford one, it sure is pretty! It has blue guts you know...

[Mark]

Microcare does well. I also have the 40A

[Mark]

Just now, plonkster said:

Wahaha! The smartflower. Wish I could afford one, it sure is pretty! It has blue guts you know...

TTT would love that 

[___]

Just now, Mark said:

TTT would love that 

He's making small-printed noises of defecting, init? :-)

[Chris Hobson]

I know Don has a solar tracker. He still needs to tell us how he does it. I briefly considered a solar tracker but decide not to based on cost and complexity. 

[Mark]

I think the gate motor on semi-circle track is the way to go... how its controlled... ????

[Chris Hobson]

1 minute ago, plonkster said:

He's making small-printed noises of defecting, init? :-)

If I had blue kit I would stay with it. Both you and TTT invested before us Voltronic clowns arrived on the scene. I have no doubt that without Voltronic we would mostly be blue and if Voltronic was available earlier you might have been tempted.

[Guest]

It was a moment of weakness ... I am allowed one or two. 

It hit me like a fist between the eyes last night when it dawned upon me that the small, very small, battery bank I have (4 x T105RE's), costs more than a 5kva Axpert.

EDIT: I am looking at grid tied SMA to power the loads daytime with the current Vickey powering the off-grid stuff 24/7. But the wife, eish, she said something about the lounge, did not hear it clearly.

[SilverNodashi]

There are a couple solar tracker tutorials, using a raspberry Pi or Arduino to track the sun - very easy to build. 

But the cost todo so if often more than the cost of adding more PV panels

[Riaanh]

47 minutes ago, SilverNodashi said:

There are a couple solar tracker tutorials, using a raspberry Pi or Arduino to track the sun - very easy to build

The easy/cheap bit are the coding, MCU, tracking, sensors etc.

When you get to the structure and motors/steppers, that is where it gets really expensive.

[SilverNodashi]

2 hours ago, Riaanh said:

The easy/cheap bit are the coding, MCU, tracking, sensors etc.

When you get to the structure and motors/steppers, that is where it gets really expensive.

On that scale, not really. You can use a wiper blade motor and a square worm drive gearbox to tilt it very easily. 

[Don]

On 3/1/2017 at 11:20 AM, Chris Hobson said:

I know Don has a solar tracker. He still needs to tell us how he does it.

Yes, I have the Deger Energie dual axis tracker. I know Chris, I said I would post something. I just can't seen to finish the installation completely. I need to take a day or 2 and just finish it. Mostly putting all the covers back covering the wires and some labels and connect up the lights. 

1. Dual axis trackers are expensive. It will probably take me 20 years to get return on investment and to justify the installation. (I wanted it and had the money, so I bought it)

2. You can reduce the number of panels by 25%, and still achieve the required kw rating with a tracker.

3. As mentioned before, rather install additional panels to make up for losses and inefficiency. It is a lot cheaper.

Consider installing tracker:

1. When you have limited roof space or your roof not facing North. 

2. Your roof is facing north, but shaded by a large tree or adjacent building for a large part of the day.  

3. You have a GTI or Infini to maximize solar production and run your panels flat out the whole day. Excess solar fed back to grid and meter running backwards. Use Eskom as "storage bank". At night use Grid/Eskom to cook a chicken in the oven with the excess you "stored" there during the day. Just make sure your meter has a positive reading when they read the meter at the end of the month, lol. 

There is no sense in installing a tracker to track the sun every minute of the day and you sit there with an Axpert with a load of 500-1000 watt. They will happily supply what you need, but without loading them, all the available excess will not be utilised. What a waste, you can then just as well stick the panels on the roof.

With a tracker you have the advantage of very early solar production and late afternoon production. I have 12 x 315 W panels = 3780 W. If I have the load, I can achieve the full capacity of my panels before 9h00 and later in the day exceed it by about 25%. 

This is my record production to date from my 3780 W Panels - 5738 W. That is 52% above design duty. 

 

 

[DeepBass9]

Must have been a solar flare or nearby supernova!

[Don]

5 hours ago, DeepBass9 said:

Must have been a solar flare or nearby supernova!

No, the wife switching on the stove and frying pan at the same time to make breakfast.