Toyota Says It Found The Key To Convince PHEV Owners To Plug In More Often

• Plug-in hybrid vehicles sometimes don’t get plugged in.
• Toyota says it found a way to change that, and it’s all based on science.
• A smartphone app that intelligently analyzes the owner’s habits gently nudges them to do the right thing.

Plug-in hybrids make a lot of sense if your daily commute is shorter than the car’s electric range, and you don’t really fancy stopping to recharge on long trips. But it all hinges on one simple thing: plugging in at the right time at home or at work.

Because there’s a gas engine under the hood, some PHEV owners don’t plug in their cars as often as they should, which means the very complicated powertrain transforms into a rather inefficient hybrid. 

But now, Toyota says it has found the answer to this problem using behavioral science. The Japanese automaker’s research institute created a smartphone app that gently nudges owners to plug in at the right time. As opposed to traditional apps that bombard users with unnecessary notifications, Toyota’s ChargeMinder prototype app delivers so-called “Just-In-Time Charging Reminders,” which pop up on the smartphone screen when the PHEV owner is most likely to plug in, but maybe forgets or gets distracted.

The app takes into account the time of day and a slew of information pulled from the vehicle to push a well-timed notification. A bit of gamification is also involved, with streaks, summaries and quizzes that make the driver feel good about their actions. It doesn’t sound like a big deal, but Toyota says it had a positive impact on the real-world behavior of several PHEV owners stateside.

The automaker conducted two pilot studies that were designed as randomized controlled trials (RCTs) to see how effective the prototype app would be. In the United States, approximately 100 PHEV owners became paid research volunteers who would test whether the app actually helps them plug in more often. In Japan, another 100 paid volunteers used the app to boost the use of renewable energy when charging all-electric vehicles (EVs).

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Both groups used the ChargeMinder app for five weeks, and in each market, the volunteers were randomly assigned to either the Treatment group or the Control group. The former got well-timed notifications to plug in, while the latter didn’t get any notifications.

In the United States, PHEV owners who were reminded by the app increased charging by 10% compared to the control group. Moreover, the notifications increased the drivers’ satisfaction with their vehicles by 16 percentage points, bringing the total to a perfect 100%.

Photo by: Toyota

In Japan, the app was tweaked to emphasize charging during peak solar hours. As a result, EV drivers changed their behavior by 59%, adding nearly 30 minutes of daily daytime charging per vehicle. This way, more solar power was used.

“Technology is not the only way to reduce emissions–people’s choices matter too,” said Dr. Gill Pratt, Chief Scientist for Toyota Motor Corporation and CEO at the Toyota Research Institute. “This research and development shows how science-based behavioral interventions can both help us reduce carbon emissions as much as possible, as soon as possible, and increase customer satisfaction.”

The ChargeMinder app is not available to the public, but Toyota said it would run other trials in new audiences and. In the long term, the app might make its way to your app store of choice.