SunSynk 5kw odd use case - battery connected no PV

[Barry Osborne]

Hi all,

I have a SunSynk 5kw inverted connected to a 15.5kWh battery (Fogstar) this inverter has no PV connected to it it just runs (inverts) the battery and does it really well. I have another inverter that deals with the PV generation.

The inverter is connected to solar assistance and then to home assistant via MQQT, this gives me full control over the battery and grid charging, i do this by the following:

I used the timer and have grid charge turned on all 6 timer slots point, I then use home assistant to change the state of charge to 100% when I want to charge and back to 14% when I don't, works like a charm.

The is pretty niche, but what options would I need to set on the inverter to do the following:

Not charge from the grid

Not discharge the battery to the load (house)

I'm with octopus agile, so I have sensor that picks the cheapest 2 hours to charge the battery each night, but sometimes the next cheapest rates are essentially the same and I don't want the battery to be used when its not worth it, lets assume the the rates for octopus agile are the below, I've assumed negative prices to prove my point:

00:00 - 00:30    -10.00p/kWh - cheapest 2h so battery will charge
00:30 - 01:00    -10.00p/kWh -cheapest 2h so battery will charge
01:00 - 01:30    -10.00p/kWh - cheapest 2h so battery will charge
01:30 - 02:00    -10.00p/kWh - cheapest 2h so battery will charge
02:00 - 02:30    -9.5p/kWh - not the cheapest 2h so battery will provide supply the power to the house - what I want to stop
02:30 - 03:00    -9.5p/kWh - not the cheapest 2h so battery will provide supply the power to the house - what I want to stop
03:00 - 03:30    -9.5p/kWh - not the cheapest 2h so battery will provide supply the power to the house - what I want to stop
03:30 - 04:00    17.71p/kWh - not the cheapest 2h so battery will provide supply the power to the house - happy with this
04:00 - 04:30    16.63p/kWh - not the cheapest 2h so battery will provide supply the power to the house - happy with this
04:30 - 05:00    15.98p/kWh - not the cheapest 2h so battery will provide supply the power to the house - happy with this
05:00 - 05:30    16.4p/kWh - not the cheapest 2h so battery will provide supply the power to the house - happy with this
05:30 - 06:00    16.4p/kWh- not the cheapest 2h so battery will provide supply the power to the house - happy with this

I've tried changing the work mode to Zero export to load and disabling the grid charge in both the timer section and the general options but it did not quite do what I expected, any tips?

Thanks,

Barry

[Scorp007]

9 hours ago, Barry Osborne said:

 

I've tried changing the work mode to Zero export to load and disabling the grid charge in both the timer section and the general options but it did not quite do what I expected, any tips?

Thanks,

Barry

My guess would be to change the SOC to say 25% when you want to discharge and untick grid charge in timer. 

Leave SOC at 100% with grid charge ticked when you want to charge during the cheap periods and prevent discharging. 

[Kalahari Meerkat]

14 hours ago, Barry Osborne said:

I've tried changing the work mode to Zero export to load and disabling the grid charge in both the timer section and the general options but it did not quite do what I expected, any tips?

are the rates between 00:00 and 03:30 actually negative, in other words they are paying you to consume electricity?

either way, whilst the rates are negative, set battery to 100%SOC, this should then charge the battery and power the load from grid and if it is full, use the grid to power the load and leave the battery fully charged...