I'm finalising the design of my ESS system and have some questions. The system is for a grid-connected house in the UK. Primarily to store excess summer PV, but also to charge the batteries in the winter from "Intelligent Octopus" or other cheap-rate nighttime electricity. The grid is generally reliable, but there is talk in the media of a small chance of blackouts this winter.
I've bought most of the system components to experiment with parts of it off-grid, before having it properly connected to the grid by my electrician.
- I've got a Quattro 10k 48v (Thought having "AC-in-2" could be useful for generator or VTL future use) - Easily meets peak household requirements.
- Cerbo GX
- Lynx Power In / Shunt / Distributor
- ET112 (If required, see below)
- 13.5kwh battery
Other
We've got 7.5kw of grid-tied solar (I might move these panels to Victon MPPT, or certainly any expansion of PV would be with Victron MPPT)
Ohme Home Pro EV charger (7kw).
I need some help deciding whether to ask for it to be connected "Grid Parallel" or have some/all loads connected to AC-OUT-1. Maybe there are some differences in ESS operation between the two options that I'm not aware of.
I did some pros/cons from what I've read (please let me know if incorrect)
Grid parallel ESS
Pros:
Quattro failure wouldn't affect the normal on-grid operation.
Cons:
In event of grid failure parallel loads on AC-in are lost
ET112 meter required at additional cost
Maybe not so responsive in keeping export to zero, as having to wait for meter data?
AC-OUT ESS
Pros:
In event of grid failure loads on AC-out-1 are supported
No need for ET112 meter
More accurate/responsive power monitoring/switching
Cons:
Quattro failure (or even restart?) would turn off loads - Could be bypassed in event of failure.
Any considerations I've missed? It looks like you must use ac-out-1 if you want to keep loads during grid failure. Grid Parallel ESS does not have UPS function.
