An API that can tell your EV when it’s the optimal time to charge

Energy management systems should mean cheaper EV charging for end users.

Credit: Aurich Lawson / Getty Images

The switch to electric vehicles is going more slowly in the US than in some other parts of the world. EVs reached a higher market share in 2020 than in any year past, but they still only accounted for 1.8 percent of all new cars and trucks. So for now, there’s not really much impact on the grid from people charging their cars at home at the same time. At least not yet. But power consumption due to EV charging will be a growing concern as the country decarbonizes in the coming years, particularly given how fragile the US’s electrical infrastructure is in places.

Just when EV charging will become a problem is something we’ve looked at before. A study by Matteo Muratori at the National Renewable Energy Laboratory in Colorado found that a residential distribution transformer could handle six EVs all charging at once, as long as those EVs were only charging at 120 V. But adding just one 240 V (level 2) charger to the mix was enough to exceed the transformer’s nominal capacity.

Muratori’s proposed solution? Smart charging.

As Ars’ Megan Geuss explained in 2018, there would be benefits to the end user as well:

Smart charging would use an energy management system that can time when an EV charges and modulate charging power accordingly. Within a demand-response program, utilities might offer cheaper charging for customers willing to be part of such a program, which would reduce the total cost of ownership of the vehicle.

Even though almost all EVs are connected cars, most of them are still pretty dumb when it comes to charging. They can be programmed to charge on a specific schedule instead of just starting the moment they’re plugged in, but the EV owner still has to decide on what that charging schedule should be and then enter it into the car’s settings.

But smart charging is starting to become more of a reality. For example, people using ChargePoint’s level 2 home charger can tell the ChargePoint app which electricity provider and rate they use, and the app will recommend charging times based on cost. The clean energy company Arcadia plans to offer a similar feature to its customers. Arcadia recently acquired a startup called Nanogrid, which developed an energy-optimization API. (Nanogrid will be familiar to Tesla owners who use Nanogrid’s Swing Electric service.)

Rather than telling users when to charge their EVs, Nanogrid’s API cuts out the human and communicates directly with the car. “A driver would preset their expected departure time when they sign up for this service (in a pre-pandemic world, they might go to work everyday at 8 am). Then, after they go for a drive and come home, they’ll plug their vehicle in. At that point, the technology powered by Nanogrid tells the vehicle not to charge right away because it’s too expensive or dirty,” said Jon McKay, Nanogrid’s CEO and co-founder.

“The technology will find the cheapest, cleanest blocks of time to charge between when [customers] plug the vehicle in and when the expected departure time that the driver had set and automatically control the vehicle’s charge rate to accomplish that schedule. We can also enable push notifications via an app or emails to confirm the optimized charging schedule, but ideally, the driver just wouldn’t have to think about it,” McKay told Ars.

As Arcadia has only just completed its acquisition of Nanogrid, it still has some work to do, but Arcadia’s founder and CEO Kiran Bhatraju told Ars that it hopes to offer some of Nanogrid’s features to its customers this summer.