Controller limits in suboptimal conditions

So, I have a Renogy Rover 30a controller being fed by 4 100w panels charging a 12 V battery bank. This puts me near the theoretical limit of what my controller can handle. E.G., 400W/12V = 28.57 amp output, near the limit.

However, my solar cells are considerably off-angle. I've never seen anything like 400w, even on a sunny august day with no shading. Can I thus "push" the theoretical limit by adding a 5th panel? While this theoretically could exceed my amp rating (500w/12v = 41.66a) I can't imagine a situation where it would do so. I could also fix this by angling the panels, but would rather spend the extra for another panel and not create "wind sails" attached to my roof.

Opinions? Also, with the Rover if I did hit a solar flare and exceed the 30a, would it fry the unit or just trip an overamp cutoff and still be usable?

From the manual for the unit, "The controller will limit the battery charging current to the maximum battery current rat ing. Therefore, an over-sized solar array will not operate at peak power". This means that the unit itself will limit the current if there is more power available from the panels that the unit is rated for. That's good. A lot of cheapie controllers don't current limit and will damage themselves in this situation.

The question then becomes one of voltage. You must never exceed the voltage rating on the controller's solar input. When looking at this voltage you have to use the VoC rating of the solar array. The controller's maximum input is 100VDC. According to the manual the controller will disconnect the solar array if the voltage from it exceeds 100VDC. This is a really good behaviour. A lot of controllers will simply burn up components if the input voltage is too high.

How are your panels arranged? All in parallel, all in series, 2 x 2 or ... ? What is the panel's VoC spec? Check the label on the back for that.

Voltage is a great point. I have four in series and adding a fifth would often exceed 100V. I should be able to fix by doing a string of 2 and a string of 3, connected in parallel. Right?

You need to keep the voltage on the strings the same, so unfortunately you can't use that configuration.

2x3 then?