First: The Petrol Reality Check
Before we talk about optimising your EV charging, let's remember what you're not paying anymore — because this context matters.
Forget the "Official" Fuel Ratings
Car manufacturers advertise fuel consumption based on lab tests. Real-world driving — with aircon, hills, traffic, and actual humans behind the wheel — is typically 20-40% higher.
What Petrol Actually Costs (Real-World)
| Vehicle Type | Real Consumption | Cost @ $1.85/L | Annual (15,000km) |
|---|---|---|---|
| Small car (Corolla, Mazda 3) | 8-9L/100km | 15-17c/km | $2,220 - $2,500 |
| Medium SUV (RAV4, CX-5) | 9-11L/100km | 17-20c/km | $2,500 - $3,050 |
| Large SUV (Prado, Patrol) | 12-14L/100km | 22-26c/km | $3,330 - $3,885 |
| Ute (HiLux, Ranger) | 11-13L/100km | 20-24c/km | $3,050 - $3,600 |
That's $2,200-$3,900 per year just on fuel. Over 5 years: $11,000-$19,500.
The EV Comparison
A typical EV uses 15-20kWh per 100km in real driving. Even at the worst charging rate (40c/kWh peak), that's only 6-8c/km — less than half the cheapest petrol car. Optimise your charging, and it drops to 1-2c/km or $0.
So yes, even inefficient EV charging beats petrol. But why pay more than you need to?
The Problem: Most EV Owners Overpay
You're already saving money compared to petrol — but most EV owners are paying 3-5x more than they need to for charging.
The Common Mistake
You come home at 6pm, plug in your EV, and it starts charging immediately — at peak rates of 35-45c/kWh. You're paying premium prices for electricity you don't need until tomorrow morning.
What You're Probably Paying
| Charging Method | Cost/kWh | Annual Cost (15,000km) |
|---|---|---|
| Flat rate (anytime) | 30-40c | $1,350 - $1,800 |
| Peak rate (3pm-9pm) | 40-50c | $1,800 - $2,250 |
| Off-peak overnight | 8-15c | $360 - $675 |
| Free solar window | $0 | $0 |
The difference: $1,500-2,000 per year between worst and best case. Over 5 years, that's $7,500-10,000.
EV Tariff Plans Compared (2025)
Several retailers now offer EV-specific plans with cheap overnight rates or free daytime charging windows.
| Retailer | Plan | Overnight Rate | Free Window | States |
|---|---|---|---|---|
| AGL | Night Saver EV | 8c/kWh (12-6am) | — | NSW, VIC, QLD, SA |
| OVO Energy | Free 3 | — | FREE 11am-2pm | NSW, VIC, QLD, SA |
| Origin | EV 360 (restricted) | — | FREE 10am-3pm | NSW, VIC, QLD, SA |
| Red Energy | EV Saver | — | FREE 12-2pm weekends | NSW, VIC, QLD, SA |
| Synergy | EV Add-On | 18.9c (11pm-6am) | 8.4c (9am-3pm) | WA only |
Note: OVO Energy's "Free 3" plan previously included 8c overnight EV charging, but this was removed in November 2025. The plan still offers the free 11am-2pm window.
Origin EV 360: Only available to customers with an Origin 360 EV Subscription (i.e., you lease your EV through Origin). Not available if you bought your EV elsewhere.
Our Pick: AGL Night Saver EV
8c/kWh overnight (12-6am) is hard to beat. Available to anyone who owns an EV — no special subscription required. You just need a smart meter. If you work from home and prefer daytime charging, OVO's free 11am-2pm window is a good alternative.
Requirements
Most EV plans require:
- Smart meter — so they can track time-of-use consumption
- Proof of EV ownership — rego or purchase documents
- Home charger — some plans require a specific charger or app
Free Charging Windows: How They Work
Why do retailers offer free electricity during 10am-3pm?
Simple: excess solar floods the grid during the day. Wholesale prices often go negative. Retailers would rather give you free power than pay to export it.
How to Use Free Windows
- Work from home? Schedule charging during OVO's free 11am-2pm window
- Have a smart charger? Set it to only charge during the free window or overnight
- Tesla owner? Use scheduled departure or the app to control timing
- Weekend warrior? Red Energy's free weekend window (12-2pm) suits occasional chargers
The Catch
Free windows are usually 3-5 hours. At 7kW home charging, you'll add 21-35kWh — enough for 100-170km of range. If you drive more, top up overnight at 8c.
Smart Chargers: Solar-Aware Charging
The ultimate setup: a charger that automatically uses your excess solar. No scheduling, no thinking — it just works.
MyEnergi Zappi
Best for: Non-Tesla owners who want automatic solar charging
Price: ~$2,000-2,500 installed
How it works:
- Built-in CT clamp monitors your solar generation
- Eco mode: Minimises grid usage, prioritises solar
- Eco+ mode: Only charges when excess solar available (pauses otherwise)
- Fast mode: Full speed, grid or solar
- Works with any EV, any solar system
- Available in 7kW and 22kW versions
Charge HQ App
Best for: Mixed-brand systems, existing charger owners
Price: App only — no hardware required
How it works:
- Australian app that connects to your solar inverter AND your EV/charger
- Adjusts charging to match excess solar in real-time
- Works with Tesla vehicles directly (no charger needed)
- Supports OCPP chargers: Wallbox, Fronius, Keba, Ocular, etc.
- Supports inverters: Fronius, SolarEdge, Sungrow, Enphase, GoodWe, Growatt
- Can also optimise for off-peak tariffs
Great for: People with existing equipment who want solar-aware charging without buying new hardware.
Tesla Charge on Solar
If you have a Tesla Powerwall + Tesla vehicle, you get this feature built-in.
Requirements: Powerwall (any model with solar) + Tesla Model 3/Y or 2019+ Model S/X
Software: Vehicle 2023.32+, Powerwall 23.12.10+
How It Works
- Enable "Charge on Solar" in the Tesla app
- Kicks in when there's at least 1.2kW of stable surplus solar
- Adjusts charge rate every 10 seconds to match available excess
- Can set hybrid mode: e.g., charge to 40% on any power, then solar-only above that
Works with Mobile Charger
You don't need a Tesla Wall Connector — Charge on Solar works with the standard mobile charger plugged into a regular 15A outlet. The smarts are in the Powerwall + car software, not the charger.
Priority Order
In Self-Powered mode, the Powerwall prioritises:
- Backup reserve (if below your set %)
- Home loads
- EV charging (excess solar)
- Battery charging (remaining excess)
The Optimal EV + Battery Setup
Here's how to charge your EV for essentially $0:
Daytime (When Home)
Smart charger uses excess solar automatically. Cost: $0
Daytime (Free Window)
OVO free window (11am-2pm). Cost: $0
Overnight Top-Up
If needed, charge at off-peak rates. Cost: 8c/kWh
Avoid Peak (3-9pm)
Never charge during peak. Your battery powers the house instead.
Battery Strategy
- Battery charges from overnight off-peak (8c) or excess solar
- Battery discharges during evening peak (40c+) to power house
- EV charges from solar or free windows
- Result: You never pay peak rates for anything
Don't Put EV Charger on Backup Circuit
EV chargers draw 7-22kW. In a blackout, this would drain your battery in 1-2 hours. Keep the EV charger off your backup circuits.
ROI: Smart Charging Pays for Itself
| Scenario | Annual Charging Cost | vs Flat Rate |
|---|---|---|
| Flat rate (35c/kWh) | $1,575 | Baseline |
| EV tariff (8c overnight) | $360 | Save $1,215/year |
| Solar + smart charger | $100-200 | Save $1,375-1,475/year |
| Optimal (solar + free window + overnight) | $50-100 | Save $1,475-1,525/year |
Based on 15,000km/year, ~4,500kWh annual charging.
Smart Charger Payback
| Solution | Cost | Annual Savings | Payback |
|---|---|---|---|
| EV tariff only (free) | $0 | $1,215 | Immediate |
| Charge HQ app | ~$100/year | $1,300+ | Immediate |
| Zappi smart charger | ~$2,000-2,500 | $1,375-1,475 | 1.5-2 years |
| Tesla Mobile Connector (with Powerwall)* | ~$550 | $1,475+ | ~4 months |
| Tesla Wall Connector (with Powerwall)* | ~$1,500 installed | $1,475+ | ~1 year |
*Requires Tesla Powerwall for Charge on Solar functionality. The Mobile Connector is sold separately (~$550); the Wall Connector adds faster 11kW charging. If you're comparing home batteries, factor in that Powerwall includes smart EV charging at no extra cost — other batteries may need a separate $2,000+ Zappi to achieve the same result.
Bottom line: Even a $2,500 smart charger pays for itself in under 2 years. Switching to an EV tariff is free and saves $1,200+ immediately.
The Bottom Line: EV vs Petrol
Let's bring it all together. Here's what 15,000km per year actually costs:
| Fuel Method | Cost/km | Annual Cost | 5-Year Cost |
|---|---|---|---|
| Petrol (medium SUV, real-world) | 17-20c | $2,500 - $3,000 | $12,500 - $15,000 |
| EV — peak charging (ouch) | 6-8c | $900 - $1,200 | $4,500 - $6,000 |
| EV — flat rate (default) | 5-6c | $750 - $900 | $3,750 - $4,500 |
| EV — overnight tariff (8c/kWh) | 1.5-2c | $225 - $300 | $1,125 - $1,500 |
| EV — solar + free window (optimal) | 0-1c | $0 - $150 | $0 - $750 |
The Gap is Enormous
Even the worst EV charging scenario (peak rates) costs less than half what petrol costs.
Optimise your setup with the right tariff, solar, and smart charging? You're looking at $50-150 per year instead of $2,500-3,000. That's a saving of up to $14,000+ over 5 years — just on fuel.
The fuel you used to pump into your car is now free sunshine hitting your roof. That's the whole point of getting the charging right.
Don't Forget Servicing
Fuel is just one part of the equation. EVs also have significantly lower servicing costs — no oil changes, fewer brake replacements (regenerative braking does most of the work), no spark plugs, no timing belts. Typical EV servicing runs $200-400/year vs $500-800+ for petrol vehicles.
When you factor in fuel, servicing, and potential tax savings through novated leasing, the total cost of ownership (TCO) gap between EVs and petrol vehicles is substantial.
See the Full Picture
Our EV Novated Lease guide breaks down the complete 5-year cost comparison — purchase price, tax savings, depreciation, fuel, and servicing. Spoiler: the EV wins by $25,000+ even with higher depreciation.
Complete the Picture with a Home Battery
A battery lets you store cheap overnight power and excess solar, then use it during peak times. Combined with smart EV charging, you can eliminate most of your electricity costs.
Calculate Your Battery Savings