A decade has passed since I drove my first modern-era electric vehicle. There have been many others since then, and the learning doesn’t stop. “EVs have all sorts of unknowns about them,” a government scientist remarked to me recently. “The manufacturers will know certain things but might not report it to the public.”
While the driving range of EVs has advanced dramatically since the 2011 Nissan Leaf, the real mileage has typically lagged behind the claims. The colder the weather, the greater the lag. But recently, some EVs I’ve driven in more favourable conditions have comfortably exceeded their rated range.
Over the past year, through three different seasons, I’ve spent time with three different, yet similar, Hyundai-Kia sibling-rival EVs. The Hyundai Kona Electric and the Kia Soul and Niro EVs are close in size and weight, and powered by the same basic powertrain – a 150-kilowatt motor juiced by a 64-kilowatt-hour battery pack. Official claimed ranges, according to Natural Resources Canada, are 383 and 385 kilometres, respectively, for the Soul and Niro, and 415 km for the slightly lighter Kona. (There’s also a 39-kWh Soul rated at 248 km.)
First up was the Kona. During a February week with the mercury ranging between -6 and +4 C, a full charge provided 250 km of mostly freeway driving with the heater on, and left 60 km of range in the “tank.” Going right down to the wire, that adds up to 310 km, or, more realistically, 290 km – 30-per-cent less than the claimed 415.
In late June, the Kia Niro EV, with the air conditioning on for much of the time, achieved an extrapolated realistic range (distance driven plus range remaining, less a 20-kilometre peace-of-mind cushion) of 434 km, well over the claimed 385 km.
In late October, a Kia Soul EV came for a weekend of mostly highway driving. At temperatures ranging between 1 and 13 C, my extrapolated range was 390 km, slightly more than the 383 km claimed.
The Soul EV returned for a full week in early March, now with temperatures mostly in the low single-digits. Driving mostly in the suburbs, with the heater on, the extrapolated range came in at 330 km, 14-per-cent less than the official 383.
No surprise that the colder the weather, the greater the range loss. I was more curious about the added range I saw in warmer weather. Is battery-pack capacity subject to production variations, I wondered? Do individual units have a little less or more storage capacity than their nominal rating?
That’s unlikely, says Sankar Das Gupta, co-founder and chief executive officer of Electrovaya Inc., a Mississauga company that supplied the batteries for the former Smart ED and now focuses on batteries for forklifts.
Battery capacity coming out of the factory, he said, “is typically consistent.” More likely, “the software could throttle back or throttle up the range.” To maximize long-term battery life, he said, EV makers don’t allow battery packs to charge fully or draw down completely, regardless of what the car’s gauges may say, so there’s some wiggle room there.
That figures. After all, Jaguar recently raised the I-Pace’s range 8 per cent by reprogramming software.
But I doubt automakers are tweaking the range of the individual cars available for press to drive. A more likely explanation lies in the test cars’ specifications. The Kona, and the top-trim Soul (Limited) and Niro EV (SX Touring) as tested, have heating, ventilation and air-conditioning (HVAC) systems based on heat pumps rather than conventional electric resistance. They also have battery heaters that improve charging efficiency in cold weather.
The Niro brochure calls the heat pump “EV range-enhancing climate control.” However, it seems government tests don’t take that into account. While the test protocol for conventional vehicles includes some driving cycles in extreme heat and cold with the HVAC operating, an older methodology without HVAC is used for EV testing, an engineer with the U.S. Environmental Protection Agency told me.
That would explain why in the case of the Nissan Leaf Plus, the S trim, which doesn’t have a heat pump, has a higher official range (363 km) than the SV and SL, which do (349 km). The higher trims are loaded with tech features that add weight and use more energy, explained Francois Lefevre, Nissan Canada’s senior manager of market intelligence and corporate planning. At the same time, the tests don’t reflect any benefits from their heat pumps.
And the specs suggests those benefits should be meaningful. Kia Canada said the Niro’s heat pump draws only 1.75 kW, versus 5.5 kW for the standard HVAC. On a small EV with a rated power consumption of about 19 kWh per 100 km, that 3.75-kW saving looks significant.
That said, heat pumps lose efficiency as the temperature falls to zero or below, so the benefit diminishes or disappears when it’s really cold. On the Leaf, for example, Lefevre says the heat pump shuts down below -10 C and the back-up resistive heater takes over. Kia Canada says the heat pump’s operating range is between -20 and +15 C.
In short, official government test range is not the whole story. We easily exceeded the official range during a summer week with a heat-pump-equipped Kia Niro. And in most parts of Canada, most of the time, cold-weather range loss should be significantly less if you drive an EV with a heat pump.
Of course, the best way to preserve or extend range is not to use the HVAC at all. Seat and steering-wheel heaters help a lot, and most EV cabins can be prewarmed or precooled while they are charging.
Here’s a list of affordable – meaning they qualify for the $5,000 federal rebate – battery electric vehicles with heat-pump HVAC systems.
- BMW i3s*
- Hyundai Ioniq
- Hyundai Kona
- Kia Niro SX Touring**
- Kia Soul Limited**
- Nissan Leaf SV**
- Nissan Leaf Plus SV/SL**
- VW e-Golf
* Optional on base i3, standard on i3s
** Specified trim levels only
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