Instructables

Solar PV tracker

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Step 4: Adding the linear actuator

I purchased the 12 volt linear actuator on Ebay. It's built to hold up in the weather, is strong enough to move however many panels I would want to add to it, and has a long enough stroke to move the panels all the way from one side to another. (I think the stroke is 8", but I'd have to double check.)

I mounted it on the one side of the frame with a through bolt, and attached it to the movable solar panel frame. To mount it to the side of the frame holding the solar panel I just used a staple on the board that moves on the bicycle wheels. A short piece of cable goes through the hole on the linear actuator and the staple, and iIused a small cable clamp to secure it. This allows everything to move around and flex as needed when it's moving. When hooked to the battery the actuator moves the panel all the way to one side, and reversing it moves it all the way back.

The next step is giving the tracker the smarts to know when and how much to move.
 
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I want to add this tracker to my solar array over the next month or two. It seems the largest consideration is going to be which linear actuator to use.

Obviously if you can find a free or cheap one from someone who is junking an old satellite dish that would be great.

But if left to buy one, other than the stroke and finding one of the appropriate voltage, how much force should one be able to exert on say, 2 45W panels and still be able to operate in blowing winds? It seems like you would want to minimize this in order to draw the lowest amount of current from your battery bank so that you gain the maximum power from your tracker and invest as little power as possible into driving the thing. Thoughts?