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Building a DIY solar panel mount: how would I calculate the parameters for a linear actuator to tilt the panels between completely horizontal and vertical? (self.engineering)

submitted 5 months ago* (last edited 5 months ago) by ikidd to c/[email protected]

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Terrible diagram 1

I'm trying to figure out how long to make A and B here if I have linear actuator of length C (extended = 2C) in order to tilt my panels from completely horizontal to vertical so they avoid wind and shed snow respectively when I run up the actuator to the extremes respectively based on sensor input.

Is there a simple formula I can use to plug the length of whatever actuator I settle on to figure A and B out? I know it will have to be a certain minimum and maximum size to work properly and might have to experiment to get an idea of what works in the end, but I'd like a reasonable start point to purchase an appropriate actuator.

I've googled around and decided I'm not smart enough to even come up with the right search criteria, let alone figure this out myself since it's been 35 years since I've used anything except the most basic trig.

This isn't really homework except for the fact that I'm trying to make my home work right.

Edit: seems like if I select A=.75C and solve for B at horizontal, then it always works out. No idea why, but the couple examples I try seem to agree.

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[–] ikidd 2 points 5 months ago

OK, so there's some way to use the idea that at retracted, b^2 = a^2 + c^2 and at extended, 2C = A + B.

Since I have a 78" long panel I was going to hinge about 1/3 of the way from the top, it seems like a 60" tall post would be a reasonable height to work from. Just plugging random numbers in, if I have an LA of 24" and randomly select A=18, at horizontal B=30 and at vertical those add up to 2C=48.

It seems like if I make A=.75C and figure out B with pythagorean, then the second equation works out as well, ie: C=18 and A=13.5, then B=22.5 and it comes out right at 2C=36. Same with C=16 and A=12, B=20 and 12+20=32.

No clue how I make the above equations prove that, but seems to work.

Thanks for reviving that part of my brain. Now I can go back to killing those brain cells with alcohol.