Just make plug-in hybrids! It’s obvious. Simple, even. It’s the solution. Read enough forums, social media posts and comments and you’ll surely learn that for yourself. Automakers seem persuaded. Everyone from Ram to Chevy to Nissan is following along.
There’s just one giant issue here. Making a plug-in hybrid is hard. Harder, even, than making a great EV. Anyone who thinks they can just spin up a world-class PHEV has another thing coming.
The issue is simple, in that the issue is complexity. Set out to make a car and you couldn’t come up with a more Wile-E.-Coyote-style solution than a car that requires a gasoline engine, electric motors, a battery big enough to run the car on its own, a charging system, a transmission and all of the software and tuning prowess necessary to blend this all together into an acceptable smoothie.
It’s no wonder many come out with more of a crunchy-peanut-butter consistency.
Photo by: InsideEVs
Lexus and Toyota have figured out how to make smooth, reliable PHEVs. But not every company has worked them out.
Just ask Consumer Reports. The average PHEV had 70% more problems than the typical gas car in its latest reliability study. That’s a worse showing than EVs—which do have 42% more issues than gas cars in aggregate—yet, astoundingly, also a remarkable improvement. In the previous year’s survey, PHEVs had 146% more issues than gas and hybrid vehicles.
“Although the BMW X5, Kia Sportage, and Lexus NX PHEVs all have average reliability, their non-PHEV versions are more reliable,” Consumer Reports said. For more proof, look to the Mazda CX-90 I’m driving this week. It’s a beautifully designed SUV from a company with a reputation for solid reliability. But it was also all-new for 2024.
“The Mazda CX-90 PHEV is the least reliable three-row SUV we have data on because of issues with the hybrid battery, electrical accessories, and climate system,” the publication said. “It’s not surprising that its unique engine, PHEV system, and rear-wheel drive setup were all designed from the ground up.”
One factor that explains this issue: new products tend to be less reliable than proven designs, a truism that also explains many EV issues. But PHEV complexity only exacerbates that issue.
Now, Mazda has addressed many of the CX-90’s issues via updates and service bulletins, and the one I’m driving feels far smoother than the reports of early examples. Yet the example is instructive.
Photo by: Mack Hogan/InsideEVs
The Mazda CX-90 PHEV I’m driving this week.
It’s just incredibly difficult to get this technology right on your first go. Unlike extended-range electric vehicles (EREVs), PHEVs do not have enough all-electric oomph to fully disconnect their engines from the wheels. Doing so streamlines design, as you don’t have to worry about blending two dissonant power sources, or figuring out the handover between them. (EREVs have their own challenges, which Kevin Williams explains in his excellent explainer on the Ram 1500 Ramcharger’s battery.)
PHEVs do have to blend their powertrains and braking systems, like a conventional hybrid. Unlike a hybrid, though, PHEVs need enough power to run for significant mileage with the engine off, and need onboard chargers to convert external AC energy into the DC power a battery needs.
That means you need every complicated part of an EV alongside every complicated part of an internal combustion engine. Improvement comes only via addition. So while an EV may be simpler to produce once you get over the hump, PHEVs will always be harder to make and package than internal-combustion cars.
This helps explain that while hybrids have achieved near cost parity with traditional gas-only engines, PHEVs remain far more expensive. This CX-90 I’m driving starts around $12,000 higher than the gas version, and only $7,500 of that can be offset via tax credits, and only if you lease it.
Photo by: Ram
EREVs like the Ram 1500 Ramcharger offer the flexibility of PHEVs, but without the need for the gas engine to ever power the wheels directly. That means you can remove a lot of the tuning work and some of the trickier components, like the transmission.
It isn’t an outlier. The average PHEV was priced just under $63,000 in July, according to Business Insider. That’s over $14,000 higher than the average transaction price of a new vehicle overall that month, $48,401 per Kelley Blue Book. That’s expected. What may surprise you is that it was also around $4,400 higher than the average transaction price for a full EV at that time.
That’s a consequence of complexity. PHEVs are harder to build and—with lower average reliability—cost more to warranty, too. Then there’s the tuning nightmare.
PHEVs must attempt to smooth the transition from the smooth, linear powerband of their electric powertrains to the mechanical, imperfect torque curve of their internal combustion engines. They must do so nearly instantaneously, at varying speeds, all while the user continues to adjust throttle inputs.
They must be quick to kill power to the internal combustion engine to save fuel, and quicker still to re-fire it when torque demand outpaces the supply from the electric motors. They must keep the engine in its most efficient operating range without letting it drone incessantly at a stable frequency, which customers hate. It is a tall order.
I drove a Hyundai Tucson PHEV last year and loved it.
Many companies have figured out how to handle it. Plug-in hybrids I’ve sampled from Toyota and the Hyundai Motor Group, which includes Kia, are great. The Chevy Volt was wonderful. BMW’s system also impressed me when I drove the X5 PHEV. Others struggled, then figured out how to overcome. Volvo’s early plug-in systems were jerky and annoying, but the new stuff is pretty good. Mazda’s CX-90 and CX-70 struggled initially, but the system seems far smoother today.
Many more, however, haven’t crossed that gap. Stellantis makes a ton of PHEVs, and while some are smooth, others aren’t. Many have reliability issues. General Motors may have also aced the Volt, but the second-generation car was designed a decade ago. Since GM just announced last year that it was once again investing in PHEVs, we’ll see if the institutional knowledge to make good ones survives that gap.
Audi has had some success, too, but Volkswagen’s push toward PHEVs remains unproven. Subaru’s plug-in hybrid Crosstrek flopped, too, with a modest electric powertrain that required near-constant interventions from the internal combustion powerplant.
Subaru’s next hybrids—the Forester and Crosstrek—are conventional models without a plug. Ford’s PHEVs may be better, but it’s hard to say for sure. While the company has sold more Escape Hybrids, Mavericks and F-150 Hybrids than I care to count, its PHEVs have had little success.
The Escape Plug-In Hybrid has done alright, but the C-MAX PHEV was basically a compliance car. And whille the company made a big deal out of launching PHEV versions of the Ford Explorer and Lincoln Aviator, they were quietly dropped after their own quality issues (which were not all specific to the hybrid models).
The Volt was the original plug-in hybrid. Too bad GM killed it before PHEVs caught on.
None of this is to say that PHEVs are a bad solution, or a doomed one.
As someone with only level one slow charging at home, who also takes an above-average number of road trips, a PHEV may be perfect for me.
Yet I see so many people acting as though they’re the easy solution. I want to dispel that once and for all. They are a solution, one we’ll need. But if you want to make a great PHEV, it’s going to take even more work than making a great EV.
Those who bet big on them before working out the kinks have a long, painful road ahead.
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