hourly grid draw

[ddmbr]

I have two "Voltronic":"InfiniSolar V x 2" also known as "IGrid SV-IV-5.6KW" from EASun. I have them in parallel config attached to pytes lithium batteries, solar, ac input attached to grid and the output to the breaker panel.

Every hour on the half hour the inverters start drawing power from the grid to supply the load for between 15 and 30 mins even when there is plenty of battery capacity. See solarassistant chart attached.

I notice that the inverter mode is switched to 'solar\battery\utility' during these periods and "solar/battery mode" when not. I have the inverters configured as follows during standard rate periods, the idea being that the load will be serviced by battery and/or solar only as electricity per kwh is 4 x cheap rate.

output_source_priority = 'Solar/Battery/Utility'
charger_source_priority = 'Solar only'

For cheap rate periods I set the following, the idea being the grid will charge the batteries when electricity is cheap as well as service the loads.

output_source_priority = 'Solar/Utility/Battery'
charger_source_priority = 'Solar and utility simultaneously'


Does anyone know why it is using the utility and how to prevent it? I thought of adding an automated wifi breaker to disable the ac input during these periods but my understanding is this could damage the inverters due to surges or inrush. Is there a setting i'm missing? Thoughts?

 

[wattmatters]

What is controlling how/when the inverter changes operating mode?

 

[ddmbr]

I have MQTT running in solarassistant on a raspberry pi attached to the console port on the master inverter and a separate linux box that runs a python script to read/write the settings via the MQTT service. The code runs every 2 minutes and uses the following logic:

if the time period is within 00:30-04:30 ( cheap rate electric) set the system to charge batteries from solar and utility and output source as utility before battery:
output_source_priority = 'Solar/Utility/Battery'
charger_source_priority = 'Solar and utility simultaneously'

if the time period is out with 00:30-04:30 ( standard rate electric) set the system to charge from solar only and battery before utility:
output_source_priority = 'Solar/Battery/Utility'
charger_source_priority = 'Solar only'

if soc > 90 reduce the charge current to minimum if during cheap rate period.
if soc > 90 reduce the charge current to minimum if during standard rate period
if soc <90 increase the charge current to 20amps if during the standard rate period
if soc < 11 increase the charge current to 30amps and switch to utility before battery and charge state to solar/utility.


I currently have the script disabled at the moment and has been for most of the day. The inverter still self switches between mode solar/battery/utility (grid draw) and solar/battery ( no grid draw) every hour for up to 30 mins. I've tried setting the mode "device_mode" via command line but it has no effect so Im assuming there has to be some internal logic that sets the value and hopefully based on properties that can be set.
Do you think its detecting something on the ac input that triggers this? If I'm in the inverter area I can hear it switching as the mode changes.

 

[ddmbr]

FYI - https://solar-assistant.io/help/integration/mqtt

 

[wattmatters]

Just throwing out ideas...

Haven't accidentally activated Solar Assistant's battery SOC management feature in the Power tab?
Check the voltage triggers set in your inverter for swapping operating modes to grid and back to battery.

 

[ddmbr]

Thanks always helps to bounce ideas around.

No SOC management set and back to battery voltage is 57 so itll never trigger and same with to grid at 47. The spikes started when I setup parallel comms so I would surmise it is firmware differences between the two inverters.

 

[wattmatters]

The spikes started when I setup parallel comms so I would surmise it is firmware differences between the two inverters.

Ah, two inverters. Yes they will need to be the same make, model and firmware I'd expect.

 

[ddmbr]

I decided to disable my automation entirely and try the ac charging timer controls. I set the start to 00:00 and end to 04:00 and the inverter time to current minus 30 minutes. So when the inverter time hits 00:00 the actual time will be 00:30 which is when cheap rate begins and similarly for charge end.

This appears to have stopped the inverter from switching to solar/battery/utility mode every hour and the draw from the grid.


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