Solar controller showing low wattage

Hello! We’re very new to solar, bought a 12 v system from SunTan Solar. We have two panels that are supposed to be high efficiency, they are also 335 watts each panel. We have hooked everything up, it’s a fairly sunny day, and our controller is showing 350 to 220 watts. Shouldn’t it be showing more as both panels combined are 770?
Thank you for any input!
Comments
A lot can be happening, your batteries could be mostly charged and the charging tapering off...
The panels might be mounted on an RV and not at a perpendicular angle to the sun.
I took a look at Their solar panel kits and I only see 250 watt panels. Perhaps they had higher wattage panels earlier?
Solar Panel Kits Archives - SanTan Solar Store
Something you should be aware of is that solar panels are rated at Standard Test Conditions (STC) but a more realistic output is Normal Operating Cell Temperature or NOCT values. These are about 75% of the STC rating. as the panels warm the cells output somewhat lower voltage and amperage. So perhaps you have 2 - 250 watt panels outputting 350 watts or (350/500=) or about 70% of the STC or about NOCT. Very light clouds can rob a lot of output.
If the batteries were close to full they accept less current, Flooded Lead Acid batteries reach this point at around 80% full then accept less current. Maximum current could also be an issue if you have a small battery bank. FLA batteries can only accept 13-15% as they approach that 80% mark. So 350 watts delivering roughly 24 amps at 14.5 volts, would represent 20% charge rate of a 120 amphour 12 volt battery bank...
So the stages of charging;
The sun really starts picking up now and I get good power for the rest of the year .
A good test is if you put a load on the system your controller should put out max power to feed your load.