Solar panel controller question.

[chuckr]

We had 390w of solar with a 2412(?) Blue Sky controller - we started with 260w and when we added a 3 panel I contacted Blue Sky and they said I could go over but absolutely do not add another panel. As we were sailing in the southern part of the Caribbean we exceed the controllers capacity many many days. We added a 4th panel but also upgraded to 3024 Blue Sky controller -
we have 2 more 6v Trojans than you do.

[masonc]

Originally Posted by chuckr

We had 390w of solar with a 2412(?) Blue Sky controller - we started with 260w and when we added a 3 panel I contacted Blue Sky and they said I could go over but absolutely do not add another panel. As we were sailing in the southern part of the Caribbean we exceed the controllers capacity many many days. We added a 4th panel but also upgraded to 3024 Blue Sky controller -
we have 2 more 6v Trojans than you do.

Exceeding the input capacity of the solar charge controller is no big deal as long as you don't exceed the voltage rating. The current generating capacity is a resource, it will take current it wants.
Voltage is a different animal, you must not exceed the rating. If you do and there is a problem, you will lose any warranty, especially if the unit has logging and the manufacturer can check.
You are unlikely to exceed the voltage rating in the Caribbean as the voltage drops with temperature. The problem comes with very cold weather when the voltage output of the panels climbs and exceeds the rating.

[masonc]

Originally Posted by carlo de leo

It's strongly recommended to install a bipolar DC circuit breaker just before the controller. So my suggestion: install this DC breaker rated at 20A, then install your new solar panel and see what happens. The controller itself may deal with an eventual extra load, you would be wasting some power if your panels exceed 20A, but you'd be safe.

This is a really bad idea. The breaker is not a current limiter, it is a safety device. The breaker for a charge controller should be rated at 125% of rated output to allow for constant current. You should not plan for the breaker to trip. If the breaker trips, it can damage your charge controller. For a 20A ma output charge controller, you need a 25A breaker, unless the breakers are constant current rated (some Midnight solar breakers).
If your solar panel rated output is more than the charge controller rating, it will not harm the controller, as long s the voltage remains within rating. You might lose some output at peak production but that's not a big deal.