title: "Scenario guide: EV owner — 10 kW PV + 13.5 kWh battery"
description: "Managing EV charging alongside a home battery in Perth — scheduling, coverage expectations and off-peak top-ups."
lastUpdated: "27 Feb 2026"
Scenario guide: EV owner in Perth
This is an illustrative scenario based on typical Perth household data, not a specific customer story.
Other loads: Evening cooking, occasional electric dryer
Daily total usage: ~25-30 kWh (including EV)
System
Solar: 10 kW PV
Battery: 13.5 kWh usable, hybrid inverter
EV charger: 7 kW single-phase (most common in Perth)
Goal: Maximise solar into both car and house, limit peak-rate grid imports
How this typically plays out
The challenge with EVs is that charging demand can easily overwhelm a battery if not scheduled properly. A 25 km commute needs ~5 kWh, roughly half a day's solar surplus that would otherwise go to the battery.
Midday charging (11 am-2 pm) is the key strategy. During these hours, a 10 kW system produces 6-8 kW. That is enough to charge the EV at 3-5 kW while still sending surplus to the battery. By starting the charge at 11 am, the EV gets most of its energy from solar.
The battery still has enough headroom to charge during the afternoon and carry the house into late evening. In this modelled setup, the battery typically provides 4-6 hours of evening coverage even after EV charging.
Cloudy weeks require flexibility. Setting the EV charger to a lower rate (e.g., 3 kW instead of 7 kW) gives the battery more solar access. During extended overcast periods, off-peak grid top-ups at night keep both EV and battery covered without expensive peak-rate imports.
Key takeaways
EV charging strategy matters more than raw PV size once you have a battery. Scheduling matters most.
A slightly bigger PV array (10 kW vs 6.6 kW) provides winter headroom when both EV and battery compete for solar.
Most EV chargers have timer functionality. Use it to restrict charging to solar hours.
On days you don't drive, the full solar surplus goes to the battery, improving evening coverage.
