The Axpert 5kVa 4000W inverter says max 3000W solar input.

If I add more to try get better cloudy / low sun charging, will it damage the inverter when full sun and more than 3000w available, or is there a chance the invertere may limit the input and only allow the 3000W?

Welcome Colin

Most SCCs can be oversized by 20-30%. I  have 3kW of panels and was considering installing a 5th string to take me to 3.75kW of PV. I have bought a 2nd Axpert so in a effort to have a more robust system I am going to parallel the 2 inverters and put 1500W of panels on the second inverter so I have abandoned the idea. Solar systems in Australia and the US are often oversized for the very reasons you present and in some cases legislation limits them to the size of inverter one may install. The only South African I know of who has oversized an Axpert's array is @Sidewinder who had 3750kW of PV. As far as I know it was very successful but he too has expanded and paralleled two Axperts .

 

I wonder if @Sidewinderand @viper_za are distantly related?

4 hours ago, Colin said:

If I add more to try get better cloudy / low sun charging,

I think that adding around 20% panel is a good idea, but for sunny days not for cloudy days.

The thing is that your 3kWp will seldom produce that amount of power, even at midday on a bright sunny day. Adding 20% is more likely to get you to that maximum when required, and your MPPT will limit it on the rare occasion that it may be able to exceed the rating.

As it turns out I am living through a perfect example right now...

It is an intermittently cloudy day in Joburg and close to midday - my panels have been putting out around 900W under cloud, adding 20% panel would raise that to about 1100W and certainly not worth the effort in my opinion - then the sun came out and raised the output to 5200W, and extra 20% would put me at around 6000W (max on my parallel Axperts) which would certainly be worth the effort.

So the point is that it is a good idea in my opinion, just don't expect a major boost in cloudy conditions.

3 hours ago, Chris Hobson said:

I wonder if @Sidewinderand @viper_za are distantly related?

hmmmmm

My system is ready for the next 3 panels.
When I installed the last 3 I already prepped the cables fuses, mountings etc for the next 3 (This was over a year ago)
All I need to do is buy mount and connect, should be less than an hours worth of work.
Will maybe do it in the next two months
 

Coming to a roof near you ... E. coli Bacteria Powered Solar Panels

I must say ... damn this is what you call "thinking outside the box", E. coli nogal. 

Thanks for all the replies 

I will put another string in this weekend hopefully, together with the new pylontech 

That should make the missus happy

52 minutes ago, The Terrible Triplett said:

E. coli nogal

It's not that surprising really. Scientists use E.coli to do a very large amount of research, in fact they grow the bacteria in the millions because it is so easy and cheap. If anyone is looking for a bacteria to try anything with, they usually try Ecoli first.

Ecoli is also a rather disappointing little sucker. Millions and millions of generations and the damn thing hasn't evolved one bit! :-P

Not related...but maybe further than splitting (should have been spitting) distance.

Btw, my system was 3600W on the axpert, but am now on 7200W on 2 x Infinis V's. So have a 5kVA Axpert waiting to be used! Just keeping it in case i end up with a real off the beaten track offgrid opportunity.

Edited July 14, 20186 yr by Sidewinder
spelling error