The PHEV Files: If My Kia Sorento Plug-In Hybrid Had A Chevy Volt Sized Battery

Here’s why I say that: the Volt is locked into an electric only drive mode by default and even pushing the accelerator all the way to the floor won’t force the gas engine to come on, typically. That means driving the Volt requires less focus on the specific pressure applied to the accelerator, in order to drive without using gasoline. Kia’s PHEV systems, by comparison allow the gas engine to be fired up much more easily and it is something people regularly complain about on social media. The Volt’s battery is bigger by about 33% though at 18.4 vs. 13.8 kWh, and its electric motor is more powerful (both of which make it easier for the Volt to operate only on battery). I don’t know, but I think the fact that the Kia has a geared transmission (rather than a CVT), or perhaps just the way it is tuned, is another reason their PHEVs will fire up their gas engines more easily. Perhaps the trade off is a quieter, more familiar gasoline powered experience though. 

The Kia Sorento PHEV starts up in electric only mode too, however if you push the accelerator down too far, the gas engine will start up and run for at least a few miles/few minutes. I put over 35,000 miles on our Volt before trading it in for the Kia, and almost 87% of those miles were driven on electricity. The 2017 Volt has 53 miles of EPA rated range on the battery (and 42 MPG on gas once the battery is depleted). I mostly drove the Volt as a commuter car and errand running vehicle though, only taking it on a handful of road trips with my family and none of those was longer than about 600-700 miles roundtrip. This is not the same way I have driven my Sorento PHEV. I only commute a fraction of the miles I used to (roughly ⅙ the distance I used to drive, or only about 1,200 miles a year for commuting, now). I also took our Sorento on several more road trips, the longest ended up being over 2,700 miles roundtrip, and as a result I have skewed my numbers downward. Specifically, I have only managed to cover about 53% of my total miles on battery in my Kia, so far (I expect that may improve a bit over time). If I were to have driven my Volt the same way, under the same conditions as my Sorento, I estimate I would have ended up with roughly 68% on battery for the Volt (given its battery is larger and its efficiency, in terms of my own miles per kWh, is also about 10% better due to being a smaller, lighter, more aerodynamic vehicle: .28 vs. .32 Cd). If my Kia Sorento PHEV had a battery as large as my Volt though, I would have covered approximately another 1,300 miles on electricity than I did with the smaller battery in the Kia. I expect there to have been a small downward trend on my gas powered miles too, since the larger battery would weigh at least a few hundred pounds more and my fuel economy would have been slightly worse.

If the Kia had an extra 4.6 kWh (or 33%) of battery capacity, I would be able to get roughly 11 more miles of range per full charge of the battery. 43 miles on a charge would be fantastic, but would still fall short of the 53 miles the Volt is rated for. In order for the Kia to get 53 miles of range on a charge, consistently, I (personally) would need about 20.5 kWh of total battery capacity (based on my miles per kWh to date average figure). Since the extra weight of more batteries would also negatively impact the fuel efficiency of my gas engine in the Kia (in addition to my miles per kWh), I would expect to lose at least 1 MPG on my lifetime average of 36.3 MPG, too. Overall, that would mean of the last 16,000 or so miles, I would have covered 61% on battery (and 636 more kWh), and the rest on gas with my lower MPG figure of 35.3 resulting in the consumption of around 31 fewer gallons of gas. If we extrapolate out to 240,000 total miles (for the sake of convenience), assuming the same pattern of usage, then the larger battery and slightly lower MPG on the gas engine would roughly equate to 48,800 kWh of electricity and 2,652 gallons of gas. Compared to what I might otherwise achieve based on what I have managed so far in my Kia PHEV, that would be a difference of 6,400 fewer kWh and about 455 more gallons of gas consumed. Note this over simplifies because the Sorento PHEV also burns gasoline to produce heat, when called for, and though such usage is factored into my 16,000 mile figure, I am guessing at the usage patterns for the remainder of the 240,000 miles. Honestly, I don’t know that the juice is worth the squeeze here, as the 6.7 kWh of additional battery would only eliminate about 455 gallons of gasoline usage over the proposed 240,000 miles, and while that is something, I don’t really know if it pencils out. I suppose it all depends on how long the additional kWh might last (the 6,400 kWh being roughly equivalent to 1,000 full charges of that capacity, which should be ½ - ¾ of their duty life). I’ll optimistically say it could be a net positive, if the batteries reach their full lifetime potential, but ultimately I think the biggest impact battery powered propulsion has is in covering that first 35-40ish miles of daily driving.

What do you think? Would having a little over 20 kWh in a Kia Sorento PHEV make it more appealing to you as a consumer? Would the extra battery, and extra cost, be worth it and if so, why? Please leave your questions and comments below.

Images courtesy of Justin Hart.

Justin Hart has owned and driven electric vehicles for over 15 years, including a first generation Nissan LEAF, second generation Chevy Volt, Tesla Model 3, an electric bicycle and most recently a Kia Sorento PHEV. He is also an avid SUP rider, poet, photographer and wine lover. He enjoys taking long EV and PHEV road trips to beautiful and serene places with the people he loves. Follow Justin on Torque News Kia or X for regular electric and hybrid news coverage.