I've studied the limit-switch problem for a week and I've decided that whatever I add on to the mount is going to be subject to failure, due to sun exposure and/or winter icing.
I think the best solution is to buy an actuator with built-in adjustable limit switches. Faster and easier too.
QARL-2418 HV-18 18" Stroke 24V Motech Heavy Duty Actuators
This one has a lot of power and should be able to do the job.
Found it for $109(shipped) on ebay.. Is there a similar unit around for less?
Edit:
Feb 22, pulled the trigger on this item. Ebay is going to ruin my retirement account!!
Edit:
Feb 23.. The Actuator is in the mail (UPS).
Edit:
March 4, replacement Actuator came today. With a little tweaking, the end-limit switches operate correctly, this one is a keeper.
It came with a UPS label to return the bad one. It's ready to go.
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I've been looking at racking for my Solar Tracker Project and I can see that
the width (~41") of the more powerful panels is going to be a problem.
So, I might try to start off with some lower power panels and use enough
to fill the racking foot print. Which I think is going to be about 8x10 feet.
Due to the short post, the center of mass is only about 6' off the ground.