Living the dream of a dual-EV garage, but how much does it cost to charge a Tesla Model Y and Model 3 at home on 240v

Spending time with the Model Y has really allowed me to get a vision into what our future garage will look like. Tonight, both my Tesla Model 3 and the Tesla Model Y are charging away happily on 240 volts.

For the past 4 days, I’ve driven the Model Y more than 700kms. What this time has enabled me to do is to live with the car, see how it would actually fit in our lives and experience what most Australian families will get to over the next decade and change, a dual-EV household.

This week I’ve been using the Model Y to do everyday tasks like running my daughter to childcare, driving to work and back, home for lunch, to the supermarket and shopping centre to buy essentials and it’s an incredibly capable car as a daily driver.

Tonight as I pulled into the garage, I had 51km of range remaining so it was time to charge. While there is a 6-bay Tesla Supercharger just 10 minutes down the road I could charge at, I wanted tonight to reflect an average night of owning a Model Y and charge using the slowest charger, the 240v mobile charger.

Having a Model 3 on the other side of the garage enables me to run a test and answer some questions.

What if both of you have 2 electric vehicles and they both need to charge at the same time?

My wife and I built our home around 5 years ago and have done nothing special to setup for this. We did think far enough ahead to put power outlets on either side of the garage, although both cars do have their charging port on the left, meaning you either have to run the cable on the ground or rig up something overhead.

Thankfully the cars are smart enough to ensure you can’t reverse over the cable, you’ll need to disconnect it before the car moves.

When I bought the Model 3 back in 2019, Tesla included a high-performance wall charger as well as the portable charger. It’s still an option to get that installed if we wanted a faster charge, but for now, it remains in the box. The HPWC costs A$780 if you buy one from Tesla and probably the same again in installation costs.

There are also 3rd party options available from places like JetCharge, but these feature a higher entry price.

The reality is, that there is plenty of power available to charge both our vehicles at one.

How much energy would that consume ?

What I tried to do today is start charging from a realistic state of charge. Most days you could probably get away with not charging, depending on your average daily drivng distance, particularly when you remember these cars both have over 400km of range.

The Model Y was down to 51km remaining (of 435km), while the Model 3 had 168km remaining.

What many people tend to do, is calculate charging time and costs based on the absolute worst case scenario and the thing about the worst case scenario, the likelihood is extremely low that you ever find yourself in that position.

Generally you’ll use your car, and just before getting out, you may glance at the remaining range and decide to plug in or not. You could of course think about it later at night and check the app to confirm if you have enough range to achieve the driving you have planned the following day.

Better yet, many will simply get in the routine of exiting their EV and plugging in the charger everyday regardless of their agenda. This means you start every day with lots of range and whatever the day throws at you, you’re ready for it.

The cars are both adding between 11-12km/hr and considering they’ll be on charge from 6PM to 7:30AM, 13.5hrs, they’ll add around 150km of range overnight. While a full charge would close to 24hrs of charging, its important to remember that 150kms is around 3x the average daily use, so for the vast majority of EV owners, charging will be a complete non-issue a few days into ownership.

Thanks to my Solar Inverter app from Solar Edge, I can monitor the energy draw from the entire house. Tonight, with both cars charging, the heater, a computer, a TV and not much else, our house is consuming around 4.1kW. The energy graph history shows prior to me starting charging, our use was hovering around 0.5kW of consumption, meaning the draw from each car is about 1.8kW.

How much does it cost ?

Charging your electric vehicle at home is by far the cheapest power you have access to and dramatically lower than fuel during the good times (often around 1/3rd the cost), but exceptionally lower right now with fuel north of $2 per litre in many places.

If I was to charge through the day, most of the energy would come from my 6.5kW solar system on the roof, but any drawn from the grid would be charged at 39.060 c/kWh.

Imagine I’m not home during the day and with Covid-19 mostly behind us, many are returning to the office, so if I’m smart, I’d charge during off-peak times and pay just half that rate at 19.810 c/kWh.

In Victoria, our energy provider, Origin Energy lists peak times as between 7 am and 11 pm Monday to Friday, outside that, is classed as off-peak. Thanks to Tesla’s ability to schedule when charging starts, you could definitely delay the start of charging until that off-peak window, to save money.

So now we understand the cost of energy, we just need to determine how many kWh of energy we need.

The Model Y SR uses the newer lithium iron phosphate battery which is est. to be 62kWh in capacity, which doesn’t mind being charged to 100% daily. When charged to 100%, the range estimate is 435kms.

The Model 3 Performance on the other hand, uses the more traditional Nikel-based that is 75kWh in capacity, but is recommended to only be charged up to 90% regularly.

Both vehicles shouldn’t be left at a low state of charge and warns you to plug in when under 100kms, with Sentry Mode also disabled under 10% of available range.

Now for the answer. It depends.

Tonight I’ll spend A$6.89 on charging two electric vehicles to get a combined 300km of extra range between the two Tesla’s.

If you do find yourself needing to go on an unplanned trip and need to charge, there’s a growing set of DC fast chargers available. If you buy a Tesla, their network costs $0.51 per kilowatt-hour, while 3rd party options like Chargefox costs 60c/kWh, 3 times what home charging at off-peak times will cost you.

While this figure is still dramatically cheaper than powering your transport with dinosaur juice, ultra-fast charging effectively comes with a convenience cost and with a tiny amount of planning, you can reduce your costs.

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Jason Cartwright
Jason Cartwrighthttp://techau.com.au/author/jason/
Creator of techAU, Jason has spent the dozen+ years covering technology in Australia and around the world. Bringing a background in multimedia and passion for technology to the job, Cartwright delivers detailed product reviews, event coverage and industry news on a daily basis. Disclaimer: Tesla Shareholder from 20/01/2021

2 COMMENTS

  1. Hi, I like that you are promoting EV’s, I do, don’t get me wrong. But you have some issues with your facts.

    1. No model Y’s have been delivered to home users in Aus yet. They’re is only display room vehicles and test drive vehicles.

    2. Your energy calculations are wrong. A standard Aus 10amp 240v outlet (which actually puts out 230v +10%/-6%) puts out 10amp x 230volt = 2.3kW. This is per car, adding 4.6kW to your household load. There will be some efficiency loss so the car won’t get all of it. Unless you reduced the amps in your Tesla app, you calcs are off.

    And 3. Basic fact, sentry mode disables below 20%, not 10%.

    I am a big advocate of EVs, I have a model 3. I do appreciate your efforts to promote EV take up but we need to educate the public with irrefutable facts so they don’t lose confidence in what we are trying to educate them about.

    • Thanks for the feedback Rusty.

      1. This is a review vehicle I have for a week.

      2. Checked both cars this morning and my estimates were pretty close, but needed to leave before 8AM, so time wasn’t exactly what I had planned.
      Model Y had 188kms of range (charged at 12km/hr), up from the 53kms when connected.. so it added 135kms of range.
      Model 3 had a range of 282km (charged at 11km/hr), up from the 163kms, meaning it added 119kms.

      3. I think you’re right, although 20% is different per vehicle, depending on your capacity.

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