AC-coupled vs DC-coupled battery: one day

Enter one day of hourly array DC power and home load. It compares where the energy goes in the two layouts.

How to enter the profiles. Give 24 numbers each, for the hours starting 00:00 to 23:00. Each value is the kWh in that hour, which equals the average kW. Separate values with spaces or semicolons. The battery starts empty and nothing is charged from the grid.

Start from:

Hourly profiles (kWh per hour)

Array DC power Home load

Settings

Inverter AC limit (kW) Inverter efficiency (%) Battery energy delivered to the home (kWh) Battery power each way (kW) AC-coupled round trip, AC to AC (%) DC-coupled solar to battery to home (%) DC-coupled charging rule

Defaults: 90% is the AC round trip on the Enphase IQ Battery 5P and Tesla Powerwall 2 AC sheets. 89% is Tesla's Powerwall 3 solar-to-battery-to-home figure. 97% is the Enphase IQ8+ CEC weighted efficiency, used here for either inverter. Battery size and power are assumptions.

Day total (kWh)	AC-coupled	DC-coupled
Array DC energy	-	-
Clipped (lost)	-	-
Direct to the home	-	-
Battery to the home	-	-
Exported	-	-
Imported from the grid	-	-
Solar to battery to home (end to end, %)	-	-
Grid to battery to home (end to end, %; DC is our estimate)	-	-

Method: hourly steps, load first, then battery, then export. AC-coupled: the PV inverter passes at most the AC limit, so clipped energy is lost, and the battery charges from AC. DC-coupled: the battery charges from the DC bus. The DC-coupled grid-charging figure is an estimate: the solar figure times the inverter efficiency. Hourly data hides short clipping spikes. Not the standard text or any manufacturer's tool; check the datasheets.