Hi
I've had a Sunsynk 8kW inverter with 2 x 5kWh batteries with 14 x 405 W panels for about 6 months now. Small house, heat pump, entire load covered by inverter. It's been working just as expected, load is prioritised during the day, batteries charge and then discharge at night etc. On sunny days, there is negligible draw from utility (Eskom). At this point no feedback into the grid (normal prepaid meter).
A typical day looks like the first image posted and is entirely expected, viz, battery starts off low, sun comes up and PV picks up, covering load and charging battery, batteries get full and then PV drops off to cover load. Sun goes down and batteries cover the base load (+- 270W with spikes when heat pump runs). See first image (before.jpeg)
This week I got an AMI meter installed (City of Cape Town). Apart from removing the prepaid meter, COCT didn't touch the PV setup. The PV installer then logged on and configured the system remotely to push back to the grid using the following system settings (see second image: AMI-settings.png)
Work mode: Limited to Home
Solar export: [enabled]
Use timer [enabled] - this setting didn't change
Inverter Power Limiter: 5000
Energy pattern: Priority Load
Grid Trickle Feed: 20
Since the AMI meter installation and changes to the settings, I've noticed some strange behaviour. The third image (today.jpeg) and fourth (flow-consumption.jpeg is the profile for today which illustrates this behaviour. The flow screenshot was taken today at 20:46 - well after sunset. Here's what I'm seeing
The battery doesn't cover the load at night and remains almost fully charged
Throughout the day and night there is a consistent 20W being fed to the grid
At night the no load on the house is present any longer (0W). I would expect to see at least the base load (370W)
During the day, the batteries charge first back to 100% - this doesn't take long as they have hardly discharged, and then the load line almost mirrors the PV line throughput the day. I can guarantee you that this is not the real load that the house is drawing.
Its almost as if the load line has replaced the grid line, but on the other side of the graph (from digging into examples, I'm expecting the grid line to display negative as the power is fed back).
Does anyone have any idea what is going on here?