Home made dual axis solar tracker

[qrper]

I've been thinking of build a dual axis tracker for years. Now that I've retired, I have some time left to tinker.
The electronic part is easy.
The challenge I see is how to do the mechanical stuff. I have searched this forum and found very little, except of one post, and I have to say, I'm impressed with what I saw. I don't have a welder, so looking for something a bit bolt on. MY thinking is to use linear actuators for both axis.
This would be for top of pole mount and should carry the weight of about 6—8 60 cell modules.

Anyone have any thoughts or plans?

Mike

[Ampster]

If you have the skills go for it. Keep up informed.

[bcroe]

Yes the electronics are trivial, kits are available. The array support with actuators
is the challenge, first to get it working, and then keeping it working. These consumer
tracker systems are likely to be quite small, will it be enough?

Alternatives are single axis tracking, and multiple facing direction extra panels. A
single axis (N-S) array does pretty well at the equator, losing efficiency farther
from it.

With panels being relatively cheap, a system can be designed with an array facing
the rising sun, another facing the setting sun, sharing the same inverters between
them. No tracker needed. The best reason I know to do that, is to increase (double
here) your output under clouds. The dispersed light will mostly keep all panels
generating, keeping the rest of the plant busy. A tracker cannot help you in that
situation, what is your cloud situation? good luck, Bruce Roe

[qrper]

Oh this is only something I want to tinker with. I like motors and things that move. Been looking at slew drives buy whoa are they expensive

[bob-n]

Here are some wild ideas, not well thought through. Pick any that may work and forget the rest:
You're talking about moving slowly, so a gear motor might be best.
Use a sprocket on the slow output shaft and drive bicycle-like chain. Or simply drive an arm tied to a nylon rope or rigid linkage.
Move each panel individually or gang them together with a flat aluminum bar.
Use a panel-size aluminum angle frame for each panel, with two corners in place (pivots) on the roof and the other two ends free to move. Have one motor drive that axis. Mount that motor on the roof.
Attach the panels to the frame similarly: two points pivoting & two points free to move, but in the other axis. Mount the second motor to the frame so it moves with the frame. It will be a harder to gang frames together in that axis, so you may need lots of motors.
If you want it to last a long time, use stainless steel for bushings and brass rods for pivots. Have a lot of clearance between rod and bushing (sloppy fit). If you're just putzing around, a pivot made from a stainless rod or bolt and a hole in the aluminum frame will last quite a while.
Exact angle is not critical, so don't make things tight. Allow some slop.
I hope some of this helps.

[J.P.M.]

Long ago as a student, I conjured up a mechanical engineers wet dream using a couple of linear actuators and a collimating tube with a pair of photocells at the bottom on a gimbal support with some circuitry and got something to work, that is, it followed the sun (but it would occasionally get a mind and notion of its own and lock onto a bright spot in the clouds on a cloudy day).

I never did get to scale it up. The real obstacles for me, as Bruce notes, and as and bob-n seems to suggest, were with the array supports and keeping the assembly operating in all kinds of weather. Also the idea that large mostly flat surfaces take a lot to keep them in one place - with that problem made all the harder if the whole thing is supposed to move in a proscribed fashion - was a deal killer for me. Nice project, but as cheap as panels are now, a fixed array is probably cheaper than a tracking array due to the extra cost of a moving support system robust enough to be reliable and strong enough to say in one location during wind events.

[qrper]

Thanks everyone for the comments. I have been kicking some ideas around in my head and nothing seems to pop out at me.

Please, everyone, this project is simply a way of tinkering and having a bit of fun. I have ground mounted arrays and yes I know the cost of adding a tracker does not make sense anymore.

But tell me. They are cool as a hell!

The north/south axis is not going to be that hard to do. A linear activator will do the job.

However the east/west axis is a completely different problem.

I thought of using a truck axle, then welding a auto flywheel to it. Then find the proper sized gear to fit the flywheel. Wait! that won't work unless I use some sort of clockworks to slow the motor down. Even if I were to find a low RPM DC motor it would still spin the main gear too fast. Yes, a PWM speed controller could be used, but I think that maybe a issue unto itself.

Same idea, a different direction. Instead of a gear drive, how about a toothed belt like they use in motorcycles? As a matter of fact, a used rear drive sprocket from a cycle would work. But then you're up against the speed issue once more.

So, how about using a differential from a small truck? Lock on side of the axle in place, and rotate the input shaft and let the differential gears provide the right angle drive and the top axle plate to connect the rack to. Once more there would be an issue with mounting a motor on the drive side of the diff. It would to be a rather beefy motor to overcome the gear loading, after all it was for a small truck.

Toss that idea out. How about this one?

Axle welded to the top plate, than an arm welded to it. A linear actuator would push/pull on this arm and move the array east/west around the center pole. I don't know if I could get enough throw to move the array from one end to the other.

Then I could simply tilt the array like Eco-worthy does in their design. I worry about this because of the number of bearings used on this gimbal type of mount. (I guess it would be the same, four bearings, no matter what the design)

OF course the whole shebang has to be built like a brick out house to deal with the weight of the frame and panels. Then be able to withstand the wind loads.

Still working on this in my head.

Mike

[morgandc]

Has anyone tried starting with the cheap packages online? For example EBay or Aliexpress