EV vs Home Power usage (Toronto)

[darkenergy]

Some of you new owners may find this valuable in understanding the electrical usage of the car vs the rest of your house. It is unlikely to match your particular circumstances, but the numbers could be used to make a fairly reasonable projection of your usage.

By way of background, just over 4 years ago we managed to get into a Toronto Hydro pilot program to monitor EV usage. We had just leased a Smart EV, installed a L2 charger and started using it as our primary vehicle.

TH provided a dedicated meter and monitoring and reporting on our car/home energy usage.

We do about 23,000 km annually in the car. The Smart is about 25% more efficient than a Tesla. It is less than a ton, doesn't go over 125km/h without a tail wind etc. There is basically 0% vampire drain over weeks.

We live in an '80s detached house, high efficiency HVAC, new windows, LED lighting, etc. I work at home.

Here's a sample report from April of 2017. Most months are similar, with July/August having a big house side boost from AC.

 

[mknox]

That report is great for showing your kWh consumption and time bands, but unfortunately does not represent your "true" cost. Toronto Hydro is only showing you the volumetric commodity cost. Missing are the volumetric transmission, distribution and regulatory costs, utility-specific loss factor and HST.

 

[Buggle]

That report is great for showing your kWh consumption and time bands, but unfortunately does not represent your "true" cost. Toronto Hydro is only showing you the volumetric commodity cost. Missing are the volumetric transmission, distribution and regulatory costs, utility-specific loss factor and HST.

I sense an accountant.

 

[mknox]

I sense an accountant.

No, a retired Ontario Electric Utility VP who was responsible for Metering, Billing/Settlements and Energy Efficiency programs.

 

[Graffi]

It is easy enough to determine the "Cost per Mile" of your EV. All you need is your average efficiency and the utility rate for electricity.

For us, our Nissan Leaf Cost us $0.03 per mile. Our Tesla Model S 75D cost us less than $0.05 per mile. I suspect our Model 3 (when we finally get it) will be in the range of $0.04 per mile.

For me, this the easiest way to look at EV fuel cost. Never mind trying to tell someone how much per month or year. It all depends on how they drive and how many miles. Everyone can understand the cost per mile. Then they can determine their cost per mile for their ICE to compare. The EV will always be less. jmho

 

[mknox]

It is easy enough to determine the "Cost per Mile" of your EV. All you need is your average efficiency and the utility rate for electricity.

Unfortunately, the way Tesla tabulates the information, it's not even close. The Tesla efficiency numbers only account for the energy that comes out of the battery pack when the car is "on". It does not account for standby losses when the car sits or for charging losses when the car charges. As an analogy, standby losses are like an ICE car with a leaky gas tank and charging losses are like spilling gas on the ground when you re-fuel an ICE car. The ICE trip computer only calculates based on gas that is burned, but you still pay for the gas that you spill when fueling and that leaks out when parked. Same with the Tesla... you still pay for the electricity lost to standby and charging inefficiencies but it isn't in that average efficiency number. For that matter, neither is any energy used when pre-heating or cooling the car remotely or if Cabin Overheat Protection is turned on.

 

[mrElbe]

When I installed my HPWC I also installed a meter in the line. So I know exactly what my Tesla consumes.

 

[Buggle]

No, a retired Ontario Electric Utility VP who was responsible for Metering, Billing/Settlements and Energy Efficiency programs.

Surely that makes you an accountant?

 

[wayner]

Surely that makes you an accountant?

More like an injunear

 

[trevorc]

Here's a sample report from April of 2017. Most months are similar, with July/August having a big house side boost from AC.

Wow I wish those were my numbers. This is me before and after gaining a Model 3 that I drive 160 km round trip when I go to work. As mknox said, I’m waiting/curious how this will pan out with all the delivery/regulatory charges when I get my bill.

 

[03DSG]

I installed this to monitor just the Model 3 circuit:

Home Electricity Monitors - Eyedro

Works great. Set the TOU rates/times and $ (including distribution etc) then create your own reports.

 

[darkenergy]

Wow I wish those were my numbers. This is me before and after gaining a Model 3 that I drive 160 km round trip when I go to work. As mknox said, I’m waiting/curious how this will pan out with all the delivery/regulatory charges when I get my bill.

My wife does 110 km round trip in the Smart, but she does have the advantage of being able to charge at the office. So our EV energy numbers would need to triple to match your charging profile.

 

[mknox]

When I installed my HPWC I also installed a meter in the line. So I know exactly what my Tesla consumes.

Me too.

 

[trevorc]

My wife does 110 km round trip in the Smart, but she does have the advantage of being able to charge at the office. So our EV energy numbers would need to triple to match your charging profile.

Yeah, about half my drive is on 400-series highways and the other half is secondary highway, so the efficiency I’m getting is probably not as good as a lot of others. Ah well - still much cheaper than $1.30/L gas!

 

[wayner]

When I installed my HPWC I also installed a meter in the line. So I know exactly what my Tesla consumes.

What is the ratio between energy drawn from the grid and energy added to the batteries? If you add 50kWh to your batteries how much do you draw from the grid? Something like 20% more?

 

[darkenergy]

What is the ratio between energy drawn from the grid and energy added to the batteries? If you add 50kWh to your batteries how much do you draw from the grid? Something like 20% more?

20% might be a bit high. While I haven't measured the model 3, I did do the Smart 3.3kW charger and found there was a loss of about 11% of the input power. Then there is a small amount from the wiring and EVSE. So maybe 15%.

However, Tesla's power electronics are pretty top notch, so maybe less than that.

Have any of you M3 owners with power monitoring done the checks yet?