Adding DIY 48 V Battery Backup to Existing 5 kW SolarEdge (Line-Side Tap) System – Advice Needed

[Colin42]

I have an existing 5 kW SolarEdge grid-tied system that’s connected via a line-side tap to my main panel.

From that main panel, I run a subpanel on a 60 A double-pole breaker that feeds selected household circuits. I have the Emporia Vue 2 and uses the Emporia EVSE to charge my car with excess solar when home.

I’d like to add my own 48 V battery bank and inverter/charger to achieve the following goals:

• Charge the battery from excess solar production during the day.
• Provide backup power to the subpanel during grid outages (automatic transfer preferred).
• Ideally, back feed to the main panel during peak rates (is this allowed by code?)

I’m aware my current SolarEdge inverter is not battery-enabled, so I assume I’ll need an AC-coupled solution (preferred) or replace the inverter with a battery-ready model.

The Battery Evo Walrus 4 looks close to what I need, but I don't see a way to vary charging based on excess solar on my main panel.


My main questions:

1. Are there any inverters/charger systems that can dynamically adjust their AC charging/discharging based on line-side current probes, so they only charge from true excess generation?
2. Are there any inverters that can back-feed through a breaker into the main panel to offset grid demand during on-peak times (while still being code-compliant)?

 

[DIYrich]

Any of the grid interactive inverters will do what you want. Put a CT on the wires to the meter, and set the inverter to "limit to home". It will read the CT to zero out draw to/from the grid.