Hi,

My dad added 4 additional solar panels to his solar system yesterday. For a period during the day the PV power is not going above 2000W. I have notice this previously, however, then it was almost his maximum power so it was not as prominent. Between about 11:00 and 13:00 the power varies between 1500W and 2000W. For this duration, the batteries was being discharge almost the whole time, so it cannot be the maximum charge current setting. It was cloudy in the morning, hence the erraticness before 11:00, however, it did clear up later. 

Has anybody encounter something like this.

Thanks

More info will help

First what inverter . Post inverter specs 

Second number of panels in series and pv specs 

 

It is a Axpert King 5kW

There are 6 strings of 2 panels. Panels are 410W & 425W (the 4 new panels are 425W).

Attached is the details of the mppt

36 minutes ago, ErickvWyngaard said:

It is a Axpert King 5kW

What is the main (U1) firmware version?
 

Kings had problems with PV before about 71.94. But they were usually characterised as "dips" (solar stopped charging for several to many minutes at a time) or freezes (solar stops charging until reset or the end of the day).

What size and length pv cable you using as 6 string are around 50amps + so if the cable is to long and thin you going to have surge issues and can only think the the controller will have an issues with  consistency especially with clouds out . 

This inverter has low volts but high wats controller  can only think that's a combination for problems with 6 strings  if pv cables are to long or to thin.  

3 hours ago, ErickvWyngaard said:

It is a Axpert King 5kW

There are 6 strings of 2 panels. Panels are 410W & 425W (the 4 new panels are 425W).

Attached is the details of the mppt

Are each of the strings wired with their own wiring to a combiner box that is also positioned close to the inverter? 

13 hours ago, Coulomb said:

What is the main (U1) firmware version?
 

Kings had problems with PV before about 71.94. But they were usually characterised as "dips" (solar stopped charging for several to many minutes at a time) or freezes (solar stops charging until reset or the end of the day).

U1: 71.90
U2: 02.40
U3: 00.24
U4: 01.10

Where can I find the latest firmware?

6 hours ago, ErickvWyngaard said:

Where can I find the latest firmware?

Right here in the files section:

 

4 of the strings (8 x 410W) are wired on one set of wires and the other two strings (4 x 425W) are on a set of wires (he thinks it is 25mm).

Point 1 on the image below is 2000W where it operates from about 10:00.
At point 2 I've asked him to disconnect the 4 x 425W strings, then the power went down to 1680W
At point 3 he put the 4 x 425W back in and removed the 8 x 410W and the power went down to 870W

So the total does not add to the sum of the two strings
 

 

Dumb question, is the new string in parallel or series?

46 minutes ago, madness_za said:

Dumb question, is the new string in parallel or series?

All strings are 2 in series as indicated. 

@ErickvWyngaard

The different connections only vary with 400W. This is not so far out when summing up. 

Did you have say about 2500W+ in load connected when you tested with all 12 connected? 

15 hours ago, madness_za said:

Dumb question, is the new string in parallel or series?

It is in parallel. 

I don't think it has something to do with the new string. I have notice it before, but then the maximum power was about 2000W so it was limited at about the maximum and for a much shorter period of the day.

15 hours ago, Scorp007 said:

All strings are 2 in series as indicated. 

@ErickvWyngaard

The different connections only vary with 400W. This is not so far out when summing up. 

Did you have say about 2500W+ in load connected when you tested with all 12 connected? 

I only had 2000W when the 12 panels was connected and the some of the two separate strings was 2500W. This was however not at the peak of the day. I will test it again today, but around 12:00 to see if there is a bigger difference. 

if i may, and what i have picked up on my inverter. 

 

using watchpower, there is a "solar balance" option. this specific option and description is a bit "wonky"

as i would happily pass the maximum charge current. with the solar balance switched OFF. it will restrict the amount of PV coming in to max charge and load current combined.  just a guess. as this setting you can see on solar assist. but you cant change it. 

It seems like it is a heat issue. We've directed a big external fan at the inverter and now it seems to work better. The inverter temperature is only around 30 degrees, so I don't understand why it would limit the power.