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chrisr asked

MPPT readings fluctuate

I'm having some strange readings on the MPPT's and PV production.

The system is Cerbo GX controlled with 2/ 10KVA inverters, 3/ 450-100 MPPTS and 8/ Pylontech 5000 batteries. PV is 5 strings of 12 panels each (60 panels) facing 45deg due South with no shading.


The MPPTs are connected to VE.Can, Batteries to VE.Bat and inverters to VE.Bus with all spare VE.Can/Bat sockets terminated.


The issue I'm having is with the PV generation fluctuating as per the video attached. 2023-02-08 09.25.47.mp4


Comparing this to another system I have running, is it severely under generating and it's strange differences between strings when they are all the same. Is there a way of seeing the commands being sent around the system so I can try and work out whether its a PV / control or component level issue?

MPPT Controllers
2023-02-08-092547.mp4 (36.5 MiB)
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1 Answer
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chrisr answered ·

This is a screengrab from VRM illustrating the problem.


I've updated the ESS settings to make sure they're set correctly as per the Pylontech config. I've also swapped over the strings to check for any wiring errors (none), I've taken one working MPPT out and reset the system just with the No1 and No3, but No3 never turns on past a few watts.

Also not sure why it's pulling from the grid when string 2 on MPPT 2 looks like it's being throttled back and not even switching no.3 on!


Each string is 12 panels, all facing the same direction (South) at the same angle with little to no shading.


I've also noticed the VECan gives an error fairly often on the MPPT's saying "device disappeared" not always the same one, I've swapped out all of the VECan cables for new ones so pretty confident it's not a broken cable.


vrm-screengrab.jpg


I'm really starting to pull my hair out on this one now!


TIA

Chris


vrm-screengrab.jpg (168.3 KiB)
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