I have a Mecer 5kva MKSII inverter with 4.260kw Solar panels and 3x US3000 Pylontech batteries.

My Panels are slightly east of North facing so it starts charging very well in the mornings but tapers of about 2 hours before sunset. I would like to put another 1.2kw of panels on our west facing roof to extend the useful day and also to help with the cloudy days.

The Max solar input for this inverter is 4.5kw, what will happen if on a sunny day at noon the combined panels deliver more than this 4.5kw? does the inverter trip or does it just take 4.5kw and the rest is lost?

I know with Victron charge controllers you can push above it and the inverter will just throttle it to the max output. 

But i suppose an expert on Mecer will be able to give you a definitive answer

An expert regarding your domain could guide you better in this problem.

 

4 hours ago, Bert sa said:

what will happen if on a sunny day at noon the combined panels deliver more than this 4.5kw? does the inverter trip or does it just take 4.5kw and the rest is lost?

The solar charge controller (SCC) will generally take enough panel power so that the solar charge controller output limits itself to its rated value. For recent 5 kVA models, this is generally 80 A. So 80 A times your battery voltage plus a few percent, so just over 4 kW. The rest is "lost" (it just heats the panels a little more than they otherwise would).

Axperts routinely overshoot their targets for a few seconds, sometimes 10 seconds or so, so you may see occasional short burts over this value.

It gets a little more complex with the high voltage SCC models, because there are additional bottlenecks, but the result is broadly the same.

Thanks guys, so it would not be a problem adding those panels.