Self setting tracker 

Thank you Rick - I have since made another of the same type to take a larger panel. Works very well.

@@Targetmaster1066 Would you happen to have a "how to" for the larger one as well?

@@MR-nl8xr Not at the moment - I'll get back to this when I've got time. Thanks for the interest.

That's just a small 25w panel - I get around 25% extra power over the day by tracking. I have the same system with a 100w panel.

@@Targetmaster1066 I had an idea for using linear actuators for roof mounted panels to take into account the low horizon sun in the winter months, but I'm unsure if you would get enough extra power to warrant the effort and expense.

It depends on you latitude - I'm at 51N. I've made dual axis trackers but found it only gives about another 8% for a lot more complication. You would be better to have a single axis tracker with just a winter/summer angle for the panel. That should give about an extra 4-5% for very little effort.

@@Targetmaster1066 yes, that was what I was thinking. Just lift the back so it points the panel lower on the horizon. I'm at 51.6N - not too different.