EVs (In Canada): FAQ

Q:  What range can I expect with an EV, and how does this change with the seasons and driving use in Canada?

A: An EVs maximum range can be estimated by taking its electrical consumption and dividing it into the size of the battery.  Most EVs will use electricity at the rate of between 15kWh and 30kWh per 100km and will have a battery pack that is between 40kWh and 100kWh.

For example:  A compact EV will use about 15-20 kWh per 100km with a 60kWh battery pack.  Maximum range would then be between 300km and 400km (60kWh / 15kW per 100km x 100km = 400km).  A large electric SUV might have consumption of 25kWh per 100km and have a 100kWh battery pack - it would have a maximum range of 400km as well.

Winter driving in Canada will give substantially less range.  The battery has more draw, including the thermal management of the battery pack and power electronics, heating the cabin, seats, rear window, as well as the other electrical accessories.  Also, winter tires with their softer rubber compounds have more rolling resistance than the harder summer tires.  Expect range to drop 30% in winter driving conditions. The chemistry of the battery also changes and slows down the movement of electrons back and forth from the annode to the cathode.  This limits charge rate and power output.

Q:  How long will it take to charge my EV at home?

A: Home AC charging speed is a function of the power available at the charging socket, the size of the vehicles on-board charger, and the size of the vehicle’s battery.  Other factors like ambient temperature and the state-of-charge of the battery are also contributing factors, though not as much so as in DC fast charging.

Power at the socket:  This equals the total available Amps x Volts.  Available safe amperage is 80% of maximum, the limitation necessary to prevent over-heating and to adhere to building codes.  A 50Amp 240V service will allow 40Amps at the plug, and charge the EV at a rate of 240V x 40Amp or 9,600w (9.6kW).  Divide the kW available at the plug into the battery size in kWh and you get the number of hours to charge the battery from empty.  For example if you have 96kWh of useable battery storage and you charge the battery at 9.6kW, then it will take you 10 hours to charge the battery from empty.  An EV with consumption of 20kWh per 100km driven 50 daily will deplete its battery 10kW every day.  This vehicle would then need to charge for about 1 hour each day at 9.6kW to replace the lost charge..

EVs have on-board chargers necessary to convert the AC power coming into the car from the electrical grid, to DC power that can be stored in it’s battery (A/C power can not be stored in a battery).  On-Board chargers vary in size, with some as low as 3.3kW and others at 11kW or more.  Some vehicles have optional, higher capacity on-board chargers.  If the capacity of the vehicles on-board charger is less than the power from the plug, the EV’s charger would be the bottle-neck and the car would only charge up to the rate of its power electronics’ maximum.

EV Battery size:  If you have a 100kWh battery pack and you are charging it at 10kW then it would take 10 hours to charge (100kWh/10kW).

A typical home installation would see a 50Amp Service at 240Volts giving a charge rate of 9.6kW.  Most new EV designs allow up to 11kW for their on-board chargers, so the vehicle can charge at the full 9.6kW.  Most EV batteries are rated between 60kWh and 100kWh.  Charging from 5%-85% would then take between 5 and 10  hours for most EVs.

Q:  What are the costs of wiring my home with an Electric Vehicle charging station?

A: Generally between $1,000 and $3,000.  An electric vehicle should have a dedicated 50Amp circuit and a 240V service to the garage where the charging station can be installed by a qualified electrician.  Upgrading the electrical supply to the home is generally not required as long as an energy management system is installed at the same time which will allow the vehicle to be charged at night.  If you wanted to charge your EV at the same time as running your stove and dryer, then you may have to upgrade your electrical service.

Q: How much electricity will my EV use in a year of driving and how much will it cost?  How does this compare to running a similar vehicle on gasoline?

A: Costs will vary depending on your driving and electricity plan, but typical use would see a large EV traveling 20,000km per year, and consuming 25kW/h per 100km of power at $.015 per kWh if charged at home.  This means using 5,000kWh of electricity annually and paying $750 for it.  In comparison an equivalent ICE vehicle might average 14 L/100km of premium fuel @ 1.30 per Litre.  That would equal 2,800L of fuel at about $3,640 per year.  Using these estimates the EV would cost $2,980 less to operate than the ICE Vehicle on an annual basis.  Carbon taxes, set to increase from $40/ton to $170/ton will increase this differential.

Q:  What is MPGe and Le/100km?

A: MPGe and Le/100km are consumption measures which are useful for comparing internal combustion engine (ICE) vehicles with those powered by electricity.   An EV will take 80% of the energy that it receives and translate it into turning wheels.  An ICE vehicle, by comparison, would be lucky to convert 20% into forward motion.

MPGe is a US measure of EV mileage.  It equates the energy in 1 US Gallon of gasoline with 33.7 kWh of electricity.

MPGe tells you how many miles an EV will travel using 33.7kWh of electricity.

A typical EV will use about 30kWh per 100miles, so will get about 100MPGe.

Le/100km is a Canadian measure of EV mileage. 1 Litre of gasoline contains the equivalent energy in 8.9kW of electricity (there are 3.79L in a US Gallon.)

Le/100km tells you how many 8.9kW units of electricity are required to travel 100km.

Q:  What is the difference between 400Volt and 800V architecture, and why does it matter?

A: Different components of the car operate at different voltages. The EV is full of ‘black boxes’ that continuously convert one form of electricity to the other, step up or down the voltage, and send each part of the car what it needs. Any transmission or conversion of electricity generates heat, which can be substantial. This needs to be managed carefully by on board electronics and liquid cooling systems. Electronics, particularly batteries, don’t like being cold either, so heating systems are needed as well to keep all the electrical components operating in an optimal thermal window.  Higher voltage is necessary to quickly generate or transmit power without generating excess heat.

If you raise the Voltage for a certain amount of power (kW) you half the Amperage.  Heat losses are proportional to the square of the Amps, so when you half the current (Amps) you quarter the heat losses.  With less heat generation the power electronics in the EV can be more efficient, which leads to faster charging and discharging of the battery.  This means more ‘repeatable’ maximum acceleration runs, and the battery can maintain greater kW for longer during the charging cycle.

Currently the Hyundai/Kia/Genesis E-GMP platform, the Audi/Porsche J1 performance platform and upcoming PPE platform, as well as the Lucid and Rimac run at 800V.

The orientation of the individual battery cells is what gives the EV its total voltage.  Batteries can be wired up positive to negative in series, which multiplies the voltage, or they can be arranged in parallel which keeps the voltage the same.  The number of cells and modules in series or parallel in the battery pack determines its voltage.

GM has created a 400/800V system with their Ultium battery packs where they provide 400V to the vehicle while in operation, but switch the 400V battery packs to operate serially which increases the voltage for charging at 800V.

Q:  How does the maintenance of the EV compare to other vehicles?

A: The maintenance requirements for an Electric Vehicle are much lower than a comparable combustion engine vehicle-at least in the first 8 years when the battery pack is under warranty.  EVs generally only require a visit to a dealer every 2 years, and that is mostly for checking the vehicle over.  Common maintenance items like fluid changes, brakes, mufflers, engine and fuel filters etc. are not required on an EV.  Tires, cabin filters and wiper blades are the generally the only things that need to be replaced during the first 10 years of an EV’s service life.  If a typical ICE vehicle averages $1,000 per  year in maintenance over the first 5 years of ownership, an EV would only be 25% of that amount.

After 10 years and 250,000km both an ICE and an EV can be expected to require investment to keep them operational.  In addition to a major service, the ICE vehicle may require additional engine or transmission work, Exhaust, and radiator.  The EV may require a new battery, or replacement of cells within the battery pack.  A new battery pack could be $20,000 or more at todays prices, though it is expected that these costs will come down. When purchasing an older EV, it is certainly worth investigating the health of the battery, and the length of time left on the battery warranty (normally 8 years and 160,000km for most manufacturers)

Q:  How long will it take to charge my EV on the road?

A: This varies considerably with several influencing factors:

1. The voltage and power output of the charging station:  DC fast charging stations can be rated anywhere from 50kW to 350kW and produce the power at either 400V or 800V.  The maximum rating may not be the power coming out of each individual plug, particularly if more than one EV is charging.  Other variables with the grid, or the specifics of the site will influence the actual charge rate.

2. Depending on the model and in some cases the optional equipment specified, EVs vary in the amount of charge they can accept at different EV charge points.  The EV’s voltage (either 400V o 800V) will determine if the power coming from the plug has to be stepped up or down in voltage before it goes into the battery.  In addition EVs have different maximum charge rates dependent on their on-board chargers and internal cabling.

3. Ambient temperature and the temperature and State Of Charge (SOC) of the EV’s battery will determine how much power the EV can accept.  EVs have sophisticated charging electronics that will monitor the state of the battery and charging station, only accepting as much current as the battery can handle without compromise to it’s long-term durability.

Actual charge rates can be anywhere from 25kW to 270kW, which will charge an EV battery from 5% to 85% anywhere from as long as 3 hours to as quickly as 20 minutes.

Most EVs will have integrated into their infotainment and navigation systems a range planner which identifies high output charging stations and plans charging points when route guidance is activated. The planning takes into account the power available at the stations and the resulting charging time for the optimum charging range and can pre-condition the battery to accept the highest possible rate of charge.  The fast charging infrastructure in Canada is experiencing rapid development, and there are still significant reliability issues.

Q: How much does it cost to charge your EV at a ‘Level 2’ or ‘Level 3’ DC Charger?

A: Rates vary and can be based on kW or time, but generally speaking you will pay between $.30 and $.50 per kWh at current rates in Canada - two to three times the cost of charging your EV at home.  Charging stations that charge by time can be anywhere from $.25 per minute to $.60 per minute, depending on the provider and the power rating of the station.

A charging session from 30% to 80% on a vehicle with a 150kW maximum DC charge rate and a 100kWh battery pack, would see 50kWh charged (.8-.3 = .5 x 100kWh= 50kWh at an average rate of perhaps 75kW (in good conditions),  taking 2/3 of one hour to charge (50kWh/75kW) or 40 minutes.

Q: Why does the DC charge rate vary so much and what is a 'Charge Curve'?

A: Every DC charging session will have a unique ‘charge curve’ that maps how many kW the battery accepts at what ‘state of charge’. Generally the on board electronics will ramp up the charge rate rapidly from 0-20% SOC, keep it at or near the maximum until about 50%, slowly decrease it to 80%, and then dramatically slow it from 80% to 100%. This is in perfect conditions. If the battery is too hot or too cold it won’t charge anything like the maximum. This is why manufacturers always quote 20%-80% charge times - this is when the battery is primed to accept the fastest charge. To get the advertised charging times conditions have to be perfect, and they seldom are. Actual DC charge times vary considerably from vehicle to vehicle, and from charging session to charging session.

Certain EVs have the ability to preheat the battery pack so that it is at an optimal temperature to accept a fast DC charge. Often this is integrated into sophisticated route planners that prepare the car for the next charging session. The EV can also be driven aggressively to heat up the battery pack prior to charging. In Canada, DC charging stations charge by the minute, so the more kW the car can accept, the less the cost of the electricity.

What this means is that it is very difficult to predict how long it is going to charge your car when you roll into a DC fast charger. Adding to the frustration, the DC fast charge infrastructure is in its infancy, and many of the chargers do not work optimally, or are out of service.

Q:  How long will the battery in my EV last, will it degrade over time, and how long is it warrantied for?

A: Most EVs come with an 8 year warranty covering the battery pack.  There are many factors that influence the longevity and performance of EV battery packs but data so far suggests high levels of sustained battery health for Electric Vehicles.  As a general rule, charging an EV more slowly, with a home AC charger will yield a longer battery service life than charging it at a DC fast charger.  Also charging the battery before it gets completely empty (5%) and charging to only 85%, will also increase battery life.  Not keeping the battery near completely empty or totally full will also help prolong life, as will occasionally excercizing the battery by running it down to 20% and then charging to 100% once per month.

Q:  What are the differences in EV battery construction, and why does it matter?

A: EV battery packs are constructed by individual cells or modules assembled into structural cases with heating and cooling circuits built in to enable the pack to be kept at a favorable temperature range.  There are many types of cells with different metals and chemistry. There are cylindrical battery cells and also ‘prismatic’ cells, sometimes called sheets, that are larger and rectangular.  They are built into modules which enable the pack to be assembled with various kWh capacities to suit different EV variants.

Battery packs can be optimized for storage density, power density, charge and discharge rate, cost and many other factors that compete against each other.  Generally speaking, the greater the quantity of individual cells the quicker the pack can charge and discharge, but this comes at the expense of complexity and cost.

Some battery packs are designed so that a bad cell or module can be replaced, leaving the rest of the pack intact.  These battery packs can be rebuilt.  Other battery packs have their cells all fused together and removing one is not possible. These battery packs can not be rebuilt.

Battery packs for most EVs range in size from 60kWh to 120kWh for cars, and up to 225kWh for large EV trucks. Matching the most efficient EV with the largest battery pack can give range in excess of 700km. Most EVs with the largest of their battery options will try to make their usable battery storage equal to 4X the consumption, giving a maximum range of about 400km at highway speeds. Since most people drive less than 100km per day, this is generally more than enough.

The cost of manufacturing EV battery packs has come down substantially, and is now in the region of $USD135 per kWh. A 100kWh battery pack costs about $13,500 today. The type of battery cells, how they are laid out in the battery pack, how they are heated and cooled, and how they are wired together influence a wide variety of performance factors including, but not limited to, voltage, energy density, charge rate, discharge rate, durability, ease of service, ease of manufacture and cost. Dead batteries can be ground up, the metals separated out, and recycled.

Q:  How much GHG can I save by driving an Electric car?

A: Driving a large luxury car or SUV for 20,000km will consume about 2,800L of gasoline, and emit about 6,500 Kg of CO2*.  Driving a similar sized EV for the same distance would use about 5,000 kWh of electricity.

Over 80% of the electricity produced in Canada come from non-GHG emitters, giving Canada some of the cleanest electricity in the world.  However, the CO2 emitted from the production of electricity varies widely throughout Canada.   Provinces that still burn a substantial amount of coal (Alberta-40%) have a mix that would emit about 3.500kg of CO2.  Quebec and Ontario generate most of their electricity through ‘clean’ Hydro and Nuclear, and the same amount of electricity produced there might emit only 500kg of CO2 or less.

The GHG emitted by electricity production in Alberta is decreasing steadily with the replacement of coal-fired generation that is to be phased out by 2030.

Producing 5,000 kWh of electricity from a home Solar installation would produce 0 GHG from operation.

Canadians on average emit about 16,000kg of C02 per year.  Switching to an EV could potentially reduce this amount by 3,000-6500 Kg per year.   The Paris Climate Change Agreement calls for Canada to reduce its GHG by 30% compared to 2005 levels by 2030.  The Government of Canada has also recently announced that it will develop a plan to set Canada on a path to achieve a prosperous net-zero emissions future by 2050.

*Source: Canada Energy Regulator.

Lawrence Romanosky, Calgary, Canada

Lromanosky@me.com, 403-607-8625