Will future EVs simplify and save weight by dropping the onboard charger?

Canada-based Hillcrest Energy Technologies aims to replace EV onboard chargers with a more streamlined system.

The company earlier this month filed a patent application for a new bidirectional charging architecture based around a high-efficiency inverter, according to a press release from the company. This eliminates the need for an onboard charger, it claims.

As we've emphasized before—and often confused by consumers—when you buy a Level 2 "charger" you're essentially buying a cable with some smart safety features built in. The conversion of the electricity from AC to DC current happens in the vehicle, in the onboard charger.

But in EVs, the vehicle's inverter already converts AC to DC current for the battery—as you decelerate. Hillcrest's solution would eliminate this redundancy, instead putting the vehicle's inverter to use, reducing cost, complexity, and weight.

Since it's not unusual for onboard chargers to lose 12-14% of the energy inputted, there could be an efficiency benefit as well.

Hillcrest also claims its system will allow EVs will 800-volt architecture to DC fast charge on 400-volt chargers without the need for a booster.

This technology is still in its early stages, however. Hillcrest said it was only completed initial "proof-of-concept lab testing," with further development work planned later this year and validation testing with a yet-to-be-named partner in 2023.

As major automakers like Volkswagen decide how to deploy bidirectional charging, this could also potentially be an inexpensive solution. It could also be more compact versus the setup, for instance, in the Ford F-150 Lightning, with dual onboard chargers adding up to 19.2 kw.

This isn't the only strategy aiming to update the extra baggage of onboard chargers. Texas Instruments is aiming to dramatically downsize them. In 2020 the company once known for its calculators began marketing new transistors it claimed could double the power density of onboard chargers, allowing components to be reduced 50% in size.