Solar + Battery + EV

What System Size Do You Really Need?

The Complete 2026 Guide for Sydney Homeowners Installing Solar, Battery & EV Charging

If you’re installing solar and you either own, or plan to buy, an electric vehicle, system sizing matters more than ever.

Too small?
You’ll still rely heavily on the grid.

Too big?
You’ll overinvest without maximising returns.

This article explains exactly how to size your solar panels, battery storage and EV charging setup for a Sydney home in 2026.

Why EV Ownership Changes Everything

An electric vehicle can increase your household electricity use by:

⚡ 2,000 – 3,500 kWh per year (depending on driving habits)
⚡ 6 – 12 kWh per full charge
⚡ 30 – 60% increase in total household consumption

That means your old “6.6kW solar is plenty” advice may no longer apply.

Step 1: Calculate Your Current Household Usage

Before adding EV charging, most Sydney homes use:

15-25 kWh per day
5,500-9,000 kWh per year

Add an EV and daily usage can jump to:

20-35+ kWh per day

The system needs to support:

✔ Daytime household loads
✔ Evening usage
✔ Overnight EV charging
✔ Battery charging cycles

How Many kW of Solar Do You Need With an EV?

For most Sydney homes in 2026:

Household Type	Recommended Solar Size
No EV	6.6kW – 8kW
1 EV	8kW – 10kW
2 EVs	10kW – 13kW+

Why larger systems make sense in NSW:

Feed-in tariffs are low
Electricity prices are rising
EV charging increases demand
Export limits restrict oversizing returns

With EV charging, self-consumption becomes more important than export income.

What Battery Size Do You Need With an EV?

This depends on how and when you charge.

Scenario 1: Daytime Charging

If you work from home and charge during the day:

Solar does most of the work
Smaller battery (10–13 kWh) may be sufficient

Scenario 2: Evening Charging (Most Common in Sydney)

If you charge after 6pm:

Battery becomes essential
13–20 kWh battery recommended
Prevents buying expensive peak-rate electricity

Scenario 3: Future-Proofing for 2 EVs

Larger solar array (10–13kW+)
20 kWh+ battery capacity
Smart load management required

Should You Charge Your EV Directly From Solar?

Yes, if system design allows.

Smart EV chargers can:

Prioritise solar generation
Divert excess solar to the car
Reduce grid imports
Work alongside battery systems

Optimised solar EV charging dramatically improves return on investment.

Solar + Battery + EV: The Smart Sizing Formula (Sydney 2026)

A simple rule of thumb:

Take your current annual kWh usage
Add 2,500-3,000 kWh per EV
Size solar to cover 80-100% of total demand
Size battery to cover peak evening loads

But real optimisation depends on:

Roof orientation
Shading
Export limits
Tariff structure
Driving habits
Future energy plans

What Happens If You Undersize?

Common mistake in Sydney homes:

Installing 6.6kW solar
Adding EV
Keeping 10 kWh battery

Result?

Battery drains quickly
EV pulls from grid at peak rates
ROI drops
Frustration rises

System design must be integrated, not added later as an afterthought.

Is It Worth Installing Solar + Battery If You Own an EV?

In NSW in 2026:

✔ Electricity prices are increasing
✔ Feed-in tariffs are declining
✔ EV adoption is rising
✔ Battery rebates are still available

For most EV owners, adding solar (and often a battery) reduces fuel costs significantly compared to grid charging alone.

Why Sydney Homeowners Trust MPV Solar

At MPV Solar, we design fully integrated systems, not patchwork upgrades.

✔ Solar sized for EV growth
✔ Battery capacity matched to real usage
✔ Smart EV charger integration
✔ NSW rebate compliance
✔ Future-proof system planning

Ready to Size Your Solar + Battery + EV Setup Properly?

If you’re buying an EV, or already own one, now is the time to ensure your system is designed correctly.

Book a free system sizing assessment with MPV Solar and we’ll calculate the ideal solar, battery and EV configuration for your Sydney home.

FAQs Solar + Battery + EV System Sizing

Everything you need to know about solar, and EV charging in Sydney.

What size solar system do I need for one EV in Sydney?

Most Sydney homes with one electric vehicle require 8kW-10kW of solar to comfortably power both the home and vehicle.

An average EV adds 2,500–3,000 kWh per year to household consumption. If your home already uses 6,000–8,000 kWh annually, a standard 6.6kW system is often undersized once an EV is added.

How many solar panels do I need to charge an EV?

Most homeowners need 6-10 solar panels dedicated to EV charging.

A modern 440W panel in Sydney generates approximately 650-750 kWh per year. Since the average EV consumes 2,500-3,000 kWh annually, 4–5 panels may technically offset usage, but 6-10 panels are recommended to account for seasonal variation and daily household loads.

How many kWh does an electric vehicle use per day?

Most EVs use 6-12 kWh per day for typical Sydney commuting.

Breakdown:

Average efficiency: 14–20 kWh per 100km
Daily driving: 30–50km
Daily energy demand: 4–10 kWh

Higher-mileage drivers may require 12–15 kWh per day.

Is a 6.6kW solar system enough for an EV?

In many cases, no.

A 6.6kW system in Sydney produces around 24–28 kWh per day on average. If your home already consumes 18–22 kWh daily, adding an EV can push total demand beyond solar production, especially in winter.

Most EV households benefit from upgrading to 8kW or larger systems.

What size battery is best for EV charging?

For evening charging (the most common scenario in Sydney), a 13–20 kWh battery is generally recommended.

This allows:

Overnight EV charging
Peak-period protection
Reduced grid imports
Greater energy independence

If charging mostly during the day, a smaller battery may suffice.

How many solar panels does it take to charge a Tesla Model 3?

A Tesla Model 3 typically requires 4–6 solar panels to offset its annual driving energy.

With annual usage of 2,200–2,800 kWh, and Sydney panels producing 650–750 kWh each per year, 4 panels may cover theoretical demand, but 6–8 panels provide better real-world performance when factoring in household loads.

Can I charge my Tesla directly from solar panels?

Yes. With a compatible smart EV charger, your Tesla can prioritise excess solar generation before drawing from the grid.

Smart charging systems:

Detect surplus solar production
Divert energy to the vehicle
Work alongside battery storage
Reduce peak electricity purchases

Do I need to upgrade my inverter when adding EV charging?

Not always, but possibly.

You may require an inverter upgrade if:

You are expanding your solar array
Your inverter is undersized
You are installing a hybrid battery system
Your current system was not designed for higher loads

A professional system assessment ensures compatibility.

How long does it take solar panels to charge an EV?

With 5kW of excess solar available, you can add approximately 25–35km of range per hour.

A typical 40–60km daily commute can often be replenished within 1–2 hours of strong sunlight, depending on charger capacity and solar output.

Is it cheaper to charge an EV with solar or grid electricity in NSW?

Charging from solar is significantly cheaper over time.

With NSW electricity prices rising and feed-in tariffs declining, using your own solar energy for EV charging delivers stronger long-term savings compared to purchasing peak-rate grid electricity.

MPV Solar is committed to providing industry-leading solar energy solutions across Sydney, backed by a proven track record of successfully completing over 5,000 projects. As a family-owned business, we prioritise personalised service and truly value our clients, ensuring that each system is tailored to meet your unique energy needs.