Short circuit one panel to reduce max voltage.

[SveinHa]

Thank you all

I have fallen down on the solution with an extra MPPT ant use 2 series on my inverter and the last panels on the extra MPPT.

I see 2 scenarios:

1. 8+8 panels on inverter and 2 panels on the extra MPPT
2. 7+7 panels on inverter and 4 panels on the extra MPPT (2 series of 2 panels each connected in parallell)

My main inverter/MPPT is EASun ISolar SMW 8K and the extra MPPT may well be EASun ICharger-4860-H. Alternative 2 seems well within specs in any worst case scenario for both units.

Problems with supply of panels and fixings at the moment so I may end up on other similar panels than those I originally had in mind.

 

[timselectric]

Option 2, seems to be better. For both chargers.
Neither will work hard, or starve.

 

[SveinHa]

My solar plant have been in operation for a couple of weeks and I have made some experiences...

I ended up on this solution:


Fairly full roof...


Inverter installation:


My theoretically 10.8kWh flooded battery pack only deliver about 2.6kWh before the voltage is so low that the inverter turns on utility charging so there are 16 pcs of EVE 280Ah LiFePO4 cells and a 200A JK BMS/2A Active balancer heading my way.

In not too bad rain, I get something around 100W. Similar grey weather without rain give me 1000-1500W. In bright sunshine, I've been up to around 7000W but that depends on how much power I can take care of. The point of installing 8.1kWp is not to get 8000w but to get as much power as possible in less than ideal conditions.

I'm impressed on how the EASun SMW 8k inverter handles variuos conditions, seamless mixing power from the available sources. One disastrous thing is the app. Fine for setting parameters but status updates may be up to 5 or 10 minutes old as worst case. Luckily, I already had a RPi installed within one USB-cable length from the inverter and I installed mpp-solar on it to get status updates to Node-Red via MQTT at about a 10 second rate.

My Node-Red dashboard (work in progress):


Looking good so far...