Ideas for the Open Source Solar Tracker (and self-introduction)

EarthOS Autarky Lab
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Hi Mark and all!

Nice project!! I think you sould define the objectives more clearly.

So, do you want total energy yield? Then no need for double orientation, just pointing south (if you are in the north hemisfere, and around 30 degrees tilted. Typical and easy.

Do you want a nice steady output along the day? Then because of panels getting 15% cheaper each year, or more, the thing could just be to have twice as many panels and have half looking to the morning sun and half at the evening sun. Tracking could still make sense I guess.

That said, I must admit I am a solar tracker fan. And in my professional time in Spain working with PV I designed many trackers on paper. Many is around 50!!!

One of the main criteria when you do a tracker is wind resistance. More about that later.

And I guess you are aiming at simplicity here.

So my recomendation is a one axis tracker but with a polar axis.

This type: File:Nellis AFB Solar panels.jpg - Wikipedia

Made by a large company with a cheap and very deployable. It is my favourite.

Check of course the wikipedia article on: Solar tracker - Wikipedia

Then for the movement I would do a mechanical system that does not get broken with wind blows. A good option there is to move the panels by the motor relocating a hanging weight, and then a damper.

My last year engineering project, in spanish, has a comparison on solar tracker models. More on that later.

I live in Berlin, met Pavlik recently here. Dont know exactly how we could collaborate. Bye!!

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Hackathon maybe?

Hello @pablo2garcia, nice to meet you. You might be interested in this hackathon coming up. Not exactly solar tracker, but still cool!

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Ideas

Hi @pablo2garcia,

Sorry I didn’t see your answer…

What you are saying is very interesting. I was wondering if it was worth having a 2 axis system - because you have a much more complicated system and I read somewhere the efficiency is increased by 5-10 %.

The second point you mentioned is the wind resistance and you’re right this is crucial of course.

I already realized (or almost) the software part. So my problem is to design the mechanical part. May be, if you have time, you could create a design of a single-polar axis solar tracker. Once I have a plan I really could go ahead on this project.

In any case, thanks for your contribution!

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There’s a friend in Wales who could use one of these.

They’ve been living off-grid for years. They use seven solar panels and three battery banks as their power system, along with a generator using bio-deisel for emergency back-up.

Each solar panel contains three large arrays of solar cells. They’ve used a micro-processor-based switching system, that switches between having all three cells in parallel and having the cells in series.

In series, they get more amps but less voltage, in parallel, they get less amps, but more voltage. They require a minimum of 14.4 Volts to charge the battery banks. (They’re using a 12V battery system.)

Because they’re based in the latitude that gives around an hour of twilight at dawn and dusk, the switching system, gives them an extra 90-120 minutes of the minimum voltage levels to charge the battery banks.

This sort of system isn’t really cost-effective for the more southerly latitudes, where the sunrise and sunset has a relatively short change-over, but the farther north you go, the more cost-effective it is.

It’s approximately a few euro’s worth of components per solar panel, and it pays for itself in three months. It also makes winter-time use a lot more feasible.

Have you considered using bicycle components for the tracking system?

Mounting the frame on a single scaffolding pole, with the pole brackets resting on skate bearings is a cheap 3d-printable home-grown solution.

Using tension wires and sailing-mast support brackets for the main lengths, and, bike chains and bike gears for the actively mechanical parts would work. It would be a cost-effective solution, that would be easy to maintain, as well as being cheap to put together from stock components.

Use a high-torque stepper motor, and a bicycle gearing system, and you’ve got the mechanical parts. And they’ll be widely and cheaply available, as well as being manufactured to a known standard.

How would you deal with the “flapping” problem?