Electric vehicle charging at home: WA tariffs, costs, and smart strategies

More Western Australians switch to electric vehicles every month. But how much does it actually cost to charge at home? And which Synergy tariff gives you the cheapest charging? Here's the breakdown.

| Level | Power | Charging Speed | Typical Use | |-------|-------|---------------|-------------| | Level 1 | 2.4 kW (standard outlet) | ~12 km/hour | Emergency/overnight top-up | | Level 2 | 7.4 kW (dedicated circuit) | ~40 km/hour | Recommended home charger | | Level 2 | 22 kW (three-phase) | ~120 km/hour | Fast home charging |

Most Perth households install a Level 2 single-phase charger (7.4 kW) — it can fully charge a typical EV overnight.

Charger installation costs

Charger unit: $800–$2,500 (depending on brand and features)
Installation: $500–$1,500 (electrical work, dedicated circuit)
Total typical cost: $1,300–$4,000

A smart charger that can schedule charging times is worth it for tariff optimisation.

The cost of charging your EV

How much electricity does an EV use?

Most EVs use between 14–20 kWh per 100km driven. The average Perth household drives about 40 km per day, which needs roughly 6–8 kWh of charging.

Monthly charging for a typical commuter:

40 km/day × 30 days = 1,200 km
At 16 kWh/100km = 192 kWh/month

Charging cost by tariff

| Tariff | Rate During Charging | Monthly Cost (192 kWh) | Annual Cost | |--------|---------------------|----------------------|-------------| | A1 (flat rate) | ~33.26 c/kWh | ~$64 | ~$766 | | Midday Saver (midday) | ~8.6 c/kWh | ~$17 | ~$199 | | Smart Home (off-peak, existing customers) | ~17 c/kWh | ~$33 | ~$392 | | EV Add-On (overnight) | ~19.4 c/kWh | ~$37 | ~$447 | | Solar self-consumption | $0 | $0 | $0 |

Compare that to petrol: a similar-sized car doing 8L/100km at $1.80/L costs about $173/month — around $2,074/year.

Synergy's EV tariffs

EV Add-On tariff

Synergy's dedicated EV tariff adds a cheaper overnight charging window:

Overnight charging window: 11pm to 6am
Rate: around 19.4 c/kWh overnight
Requirements: a separate meter or smart meter that can record EV usage
Best for: overnight charging when you don't have solar

Smart Home Plan (existing customers only)

The Smart Home Plan is a time-of-use plan that also suited EV owners. Note: it is no longer available to new Synergy customers. If you're already on it, the off-peak rate applies overnight:

Off-peak rate (9pm–7am): around 17 c/kWh, lower than the A1 flat rate
No dedicated EV meter required
Peak rate (3pm–9pm): around 62 c/kWh — avoid charging then

For new customers looking to save on overnight EV charging, the EV Add-On tariff is the current Synergy option.

Midday Saver + Solar

If you have solar and charge during the day:

Grid rate during midday: ~8.6 c/kWh (if your solar isn't quite enough)
Solar self-consumption: effectively free
Best for: work-from-home or daytime charging setups

Smart charging strategies

Strategy 1: charge from solar (best savings)

If you have a 6.6 kW+ solar system, charge your EV during the day while the sun is up.

Cost: $0 (solar self-consumption)
Requirements: daytime charging (work from home, or plug in when you get home while the sun is still up)
Smart charger feature: some chargers detect excess solar and charge only from the surplus

Annual saving vs the A1 tariff: about $766

Strategy 2: EV Add-On night charging

For households that drive during the day and charge overnight:

Schedule the charger for 11pm–6am
The overnight rate applies
Cost: about $447/year for a typical commute
Annual saving vs the A1 tariff: about $319

Strategy 3: Solar + Battery + EV

The full setup:

Solar charges the battery during the day
The battery powers the house in the evening
The EV charges from the grid overnight on the cheapest rate
Or the EV charges from solar during the day

Combined annual cost for EV charging: as low as $50–$100/year with well-scheduled charging.

Sizing your solar system for an EV

Adding an EV typically adds 6–8 kWh of daily electricity demand. To cover that with solar:

Extra solar needed: 2–3 kW of panels
On a 5 kW system? Consider an upgrade to 7–8 kW
On a 6.6 kW system? You may already have enough surplus

Use BillWise's scenario tool to model the exact impact on your bills.

V2H and V2G: the future

Vehicle-to-Home (V2H) and Vehicle-to-Grid (V2G) technology is emerging:

V2H: use your EV battery to power your home during peak hours
V2G: export power from your EV back to the grid for credits
Status in WA: not widely available yet, though some vehicles support it with a compatible charger

Once V2H becomes mainstream, your EV battery (typically 60–100 kWh) could act as home energy storage far larger than any dedicated home battery.

Charger recommendations for WA

For Perth households, a few options stand out.

Budget option:

Any 7.4 kW Mode 3 charger with a timer
Set the timer for your cheapest tariff window
From ~$800 installed

Smart option:

A solar-aware charger (e.g. Zappi, Tesla Wall Connector)
Automatically adjusts charging to use excess solar
From ~$1,500 installed

Premium option:

A three-phase 22 kW charger with solar integration
Fast charging plus full smart control via app
From ~$2,500 installed

Calculate your EV charging costs

Your actual costs depend on your tariff, solar system, driving patterns, and charger setup. BillWise can model all of it:

Upload your bill — we'll read your current tariff and usage
Run an EV scenario — add EV charging to see the impact
Compare tariff options — find the cheapest charging tariff for your profile

Start your EV cost analysis →

The bottom line: charging an EV at home in Perth costs a fraction of running a petrol car, and with the right setup — surplus solar plus the EV Add-On overnight rate — you can charge for just a few cents per kWh.

EV Charging at Home: Everything You Need to Know -- Our complete guide to home EV charging setup, equipment, and installation in WA.

Ready to compare EV charging costs? Calculate your savings → — includes a petrol vs EV comparison with live FuelWatch prices, so you can see exactly what switching saves you.