I say this not to discourage anyone from considering a PHEV as their next vehicle. They are excellent, potentially necessary bridges to the EV lifestyle, offer some flexibility that EVs do not as well as the opportunity to achieve significantly better fuel economy than HEVs on short to medium distance drive cycles. But for them to ever make economic sense, to recoup their extra cost, and to make ecological sense as well, they must be plugged in routinely, and multiple times a day if needed. On very long road trips (of several hundred to thousands of miles) one will not have as much opportunity to charge unless making the trip in short to medium stints of 50 -150 miles at a time. So, if one is making a decision about a PHEV purchase based on the bottom line, it is important to consider whether the additional cost of a PHEV will be recouped over time by the ability to drive mostly on electricity for short to medium distances. If one drives a majority of their miles on long distance highway cycles, a PHEV may never make financial sense. Likewise, if one lives where electricity costs are high and gasoline costs are low, it may compound the financial equation for PHEVs vs HEVs or EVs.
Our odyssey ended up being 2,718 miles in total, from Seattle, WA down to Anaheim, CA via Sonoma, CA and the Oregon coast. This was a trip that included many hazards, including dodging a familial visit due to a COVID infection at our first stop, chasing a hurricane (ne tropical storm) through southern California, an earthquake on our way, and forest fires so bad we had to reroute our drive home which meant we missed out on our planned activities in the redwoods (due to smoke). On the trip, we used 66.9 gallons of gas and approximately 85 kWh of electricity, which translates to roughly 10% of the miles covered on electricity and 90% on gas. Running the numbers, that means I got about 36.6 MPG, combined. For a 3-row, midsize SUV like the Sorento PHEV, on a very long trip like this, that isn’t bad. I charged the battery fully about 7 times at places we stayed overnight (friends and family’s houses or the hotel we stayed in) or spent the day at (a theme park). I only spent about $5 for the 85 kWh I used in total. Gas was fairly expensive though, at an average price of $5.17 per gallon, so paying less than 40 cents per kWh to charge was worth it (equivalent to paying between $4 and $4.50 per gallon). All told, I spent about $351 in fuel to make the trip and got to see some beautiful scenery up close, too.
Important findings from our return trip began on the Tejon (aka the Grapevine) Pass. When we were headed down to Anaheim, my wife only managed to get about 31 MPG going over the pass, in Sport Mode and used up a third of the energy stored in the battery by the time we reached the high point, even with Sport Mode recharging it. I drove us back over the pass in Eco + HEV mode, again with about 12 miles of range remaining on the battery. I managed to get 34 MPG and did not lose any range from the battery, heading north. I expect this was due to my slower overall speed (60-65 MPH instead of my wife’s 70+ speed), but a different slope/less demanding climb could also be a factor in the better MPG figure going home. I don’t know which approach, north or south, might be more demanding on the vehicle. I’ll suggest that speed, more than anything, determines fuel efficiency though and suggest that this is another example of such. I’ll also point out that by the time we reached the bottom of the pass, going home, our battery state of charge reflected 19 miles of range, which is more than what we saw headed south when it only returned to the 12 mile figure we had at the start of the climb. That suggests that the northbound route may have a little more downward slope.
On the return journey, I also learned that you can force Smart Mode out of EV mode by pressing the HEV/EV button until it displays “HEV” on the dashboard display. I am pointing this out since I incorrectly assumed that Smart Mode “chose” to use up my EV range in a previous article; it actually just defaults to that just like in Eco mode. I also saw that Smart mode (like the HEV Mode does as well) will turn off the gas engine when coasting downhill whereas the Sport Mode would not, per se (it may eventually, but is slower to do so). This was just one more reason I am now certain that, in short to medium distance applications in particular, Sport Mode is likely to be less efficient than the other modes. It still may be useful or desirable for maximum performance, but will ultimately challenge one's ability to get the best possible fuel efficiency in those situations.
But what if a trip like this had included perfectly situated charging options and what if the Sorento PHEV could have charged up to 3x faster at my stops, in a sort of ideal PHEV scenario? Or, what if the capacity of my PHEV battery were 3x larger? Though none of these scenarios are reality at this point, my calculations suggest that a faster 240V charging rate would have added, at most, about 50 additional miles of electric only driving to my trip (since that faster speed would only have applied to the stops I made for 30 mins or less, rather than overnight). Even if I could have charged at a rate similar to what the Mitsubishi Outlander PHEV can (50kW on 480V), and I stopped a little more often or for longer than the 10 mins or so I mostly made stops for, it would not have added much more range. However, if perhaps the battery were 2-3x larger and capable of faster than 50kW charging while I was simultaneously adding gas, using facilities or having a snack or a stretch, then perhaps I could have added hundreds of miles of electric range (but that basically describes a fully electric vehicle). I guess what I am trying to get at here is that I don’t think we really need to keep making PHEVs with larger and larger batteries. Yes, it is good to offer people choices and a range of battery sizes, but sizing the battery to match about 1-2 gallons of gasoline range is the best configuration for a PHEV. Otherwise, one is lugging around a combustion engine they hardly ever use (which is a waste of resources and just adds unnecessary maintenance, though one could legitimately make this argument about all PHEVs, regardless). People who drive more than the distance of the battery on a regular basis may want to consider either fully electric vehicles or standard, non-plug-in hybrids for a more economical solution and better use of limited resources.
Any questions about the performance of the Sorento on very long road trips? Any different perspective on the application of larger batteries in PHEVs or techniques for using them on long trips? Please leave any comments or questions 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 https://www.torquenews.com/kia for regular electric and hybrid news coverage.