First, the scenario: With rotational power cuts ("loadshedding") upon us again here in South Africa I have set my Minimum SoC in the ESS menu to 40%. This leaves me enough battery reserve to endure the worst overnight loadshedding I've experienced so far.
The issue I have is that the Multi will always recharge the batteries from the grid if the SoC falls below 40%. This costs me money, often unnecessarily, because tomorrow the sun will recharge my batteries for free. I want it to only recharge from the grid once the battery level falls critically low, say 15% SoC.
Effectively, I want ESS to manage my battery SoC levels as follows:
- Below 15% SoC: Do not discharge the batteries if the grid is available. Charge the batteries from the grid, if available.
- Between 15% and 40% SoC: Do not discharge the batteries if the grid is available. Do not recharge from the grid.
- Above 40% SoC: Freely discharge the batteries regardless of whether the grid is available or not.
This doesn't seem possible without resorting to hackery, or am I missing something? Consider this a feature request if my assessment is accurate.
A way to overcome this limitation would be a Maximum SoC for Grid Charging option in the ESS menu (with a default of 100%). I could set it to 15% to achieve my goal of only charging from the grid when the battery level has fallen critically low.
Note that this option should not disable the charger in the Multi entirely, since excess power from AC coupled PV should always be utilized to charge the batteries.