SunSaver 20

I'm using a SunSaver 20 amp charge controller. I do not have an ammeter. Presently, I have 3 100 watt Harbor Freight solar panels feeding the charge controller and haven't had any problems. I use a Harbor Freight 7 input-1 output junction box.

The problem is that I don't know how many actual amps the panels produce. This area, Greenville, VA, gets many more cloudy and overcast days than it does clear. I want to add another solar panel. That would make 4 panels feeding the SunSaver 20.

Twenty divided by four equals five amps. Although the nominal maximum current from each panel should be 100 watts divided by 12.6 volts, which is about 8 amps, I doubt that the panels regularly produce 8 amps. On the cloudy and overcast days, I'd be surprised if they made even 1 amp.

The reality of my use of solar panels is that I need to rely upon them to keep my freezer running even on overcast days. The freezer is rated to use about 1.1 amps at 120 volts, and therefore is not a large draw, but it's large enough to give me problems.

Will connecting 4 100 watt panels to the SunSaver 20 cause damage? If an overload shuts it down, instead of burning it up, I'd just venture a try.

What do you reckon will happen with the charge controller? Shut down or burn up?

I presently have 3 other panels charging the batteries through Harbor Freight controllers.

What usually happens when you massively overload an inexpensive pwm charge controller is the complex circuitry in it that allows it to "pulse" gets fried and you end up with a simple on off switch. The problem is it will allow much higher voltages to the batteries then it should and you boil your batteries shortening their lives. If you have several hundred watts of solar at this point you should invest in a single larger mppt charge controller. One charger reading the batteries unaffected by others would give you much better charging and an mppt charger works much better in cloudy condition.
Cheers, David

The user manual claims it will shutdown. It also says to install a fuse or circuit breaker.  

One idea might be to orient the panels at different angles so that at any given hour on a sunny day, not all the panels will get direct sun, but on a cloudy day they’ll all receive diffuse light.  ( This could be say 1 aimed SE, 1 S, 1 SW, 1 layed flat and aimed straight-up or even slightly north)

It's really a non-issue.  Solar panels almost never put out their rated output, because that's determined in an artificial test chamber with artificial light.  If you ever get even 5A out of one of those panels, consider that to be amazing.  If you really want an accurate measure of what your real-world output is, borrow a clamp meter that can read DC current.  I have a Uni-T216C clamp, that can read DC amps, AC amps, and AC inrush current.

In the long-run though, I agree with other posters suggestions to upgrade to MPPT.  Take a look at Epever's Tracer 4210AN.  You pay a price premium for 12V automotive panels.  You'll get more bang for your buck going MPPT, which will allow you to use high-voltage residential panels for your 12V system.  The cutoff is ~300W.  With systems implementing more than 300W of solar, MPPT and residential panels will actually be cheaper than sticking with older PWM technology.  A MPPT controller acts as a transformer, taking raw high-voltage solar, and transforming down to battery voltage, making extra charging amps out of the extra volts.