Modified Rivian R1T Aims for EV Cannonball Record With Dual-Battery Setup

A DIY Attempt to Push Rivian’s Range Limits

A standard Rivian R1T is known for its capability and rugged design, but long-distance efficiency has never been its strongest suit. With modest charging performance and average energy efficiency, it is far better suited for commuting or off-road adventures than nonstop cross-country driving. Even so, a group of dedicated EV enthusiasts is determined to change that by building a unique, long-range R1T specifically for an EV Cannonball Run attempt.

Their project—documented in a recent video by Robert Dunn of Aging Wheels—centers on converting a first-generation R1T into a dual-battery, dual-charging electric truck capable of traveling over 600 miles on a single charge. The effort is entirely independent of Rivian, despite the involvement of a few Rivian employees acting on their own time.

Building a 310 kWh Super-Sized Battery System

The base vehicle is a 2022 Rivian R1T Quad Motor equipped with the 131-kWh Large Pack, which offers an EPA-estimated 314 miles of range. Good—but nowhere near enough for a competitive Cannonball Run. To address this, the team sourced two nearly new battery packs from Rivian vehicles totaled during IIHS crash testing.

After disassembling the donor packs, they managed to fit 12 additional battery modules into the truck bed, more than doubling the vehicle’s usable capacity. Combined with the factory 131-kWh pack, the modified R1T reaches 310 kWh of total energy storage. At an estimated average efficiency of 2 miles per kWh, theoretical range climbs to roughly 620 miles.

To integrate the system, the team identified a high-power bi-directional converter capable of linking the bed-mounted pack to the truck’s high-voltage system. A custom junction box taps into the wiring between the main battery and the motors, allowing the auxiliary pack to supply power, receive charge, and even transfer energy back to the primary pack as needed.

Cooling, Charging, and Practical Challenges

With so much energy onboard, cooling became a priority. The team designed a basic but effective solution: a water pump, a compact radiator, and even bags of ice for thermal management. The auxiliary pack can be charged independently from a DC fast charger, enabling both batteries to recharge simultaneously at two different stations—an advantage during a timed record attempt.

However, the add-on pack is not fully weatherproof, which caused significant challenges during early testing. Heavy rain and harsh conditions ultimately forced the team to abandon their first Cannonball attempt, despite the impressive technical achievement.

Chasing the EV Cannonball Record

A true Cannonball Run from New York to Los Angeles is roughly 2,800 miles. A conventional car sticking to legal speeds would require about 42 hours. The overall record—set by a modified Audi S6 in 2020—is 25 hours and 39 minutes. The current EV record, set by a stock Porsche Taycan in 2023, stands at 39 hours and 29 minutes.

The Rivian team regrouped after their initial setback, improved the design, and prepared for a second attempt. A new video documenting the run is expected soon and should clarify whether the modified R1T has finally dethroned the Taycan as the fastest EV to cross the United States.

A Showcase of Ingenuity, Not Corporate Engineering

While Rivian had no involvement in the project, the effort highlights how flexible electric platforms can be—and how far determined enthusiasts can push them. Whether or not the team secures a new EV Cannonball record, their 600-mile dual-battery R1T stands as one of the most ambitious garage-built EV experiments to date.

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