Not getting full wattage from the roof

[JohanDurban]

Hi guys, 

I recentrly installed an Axpert King, with 12x400W panels on the roof and 4x200aH batteries in series. 

I have noticed putting the dishwasher on, that it is still pulling from batteries, but the load is below the 4800W im expecting from the roof.

Im new to this, so did they install it correctly, or am i misunderstanding how this works? I live in Durban, and its a cloudless day with our famous Durban heat

 

[Gelo]

I stand to be corrected here but u can expect a 20% drop from the 4800watts from the pv array even at peak, no expert here but this is due to wiring loss and so on, so in essence your looking at 3840watts weather dependant and mounting angle, panel temps the list goes on and on (once again I stand to be corrected)

I believe if the wattage produced by Pv array was not sufficient and the inverter then chose to draw from battery bank to cover load

 

What readings where you getting from inverter on the Pv at that specific point?

[alyusuph]

In very rare situations I been getting more than the PV Wattage 3.1KW 100 watts more)  for short periods at around 11.00 AM even though the PV orientation is North West my setup is -15 X 200Watts Forge Poly PVs connected in series + 5KVA Victor NM II Inverter. 

[Coulomb]

23 hours ago, JohanDurban said:

the load is below the 4800W im expecting from the roof.

As others have noted, it's rare to get the nominal power from panels for any length of time. The best you can expect long term is about 80% of nominal, but only about an hour either side of solar noon, and of course if there are no clouds, panels aren't dirty, good orientation and tilt, etc etc.

That said, as alyusuph posted above, you can get more than rated power for brief periods (less than a minute), due to cloud edge effects, when the panels are cooler because of earlier cloud, and so on.