How do we solve the weight problem of EV heavy trucks?

Ian Rust
3 min readJan 17, 2024

--

In 2019, Congress added 2,000 pounds to the weight limit for heavy trucks if they are battery electric. This was done to help offset the extra weight that inherently comes with BEVs to help with adoption. Previously class 8 heavy trucks had a firm weight limit of 80,000 pounds. Unfortunately even with that limit raised to 82,000 pounds, EV semi trucks on average require sacrificing 5,000 pounds of cargo-carrying capacity. So a diesel truck that was running at 77,000 pounds Gross Vehicle Weight (GVW) could be legally replaced with an electric truck. A 77,001 pound GVW diesel truck could not.

When you look at the distribution of class 8 truck weights, this may seem a perfectly acceptable sacrifice, with the vast majority of trucks easily able to fit the extra weight of a battery.

Source: Federal Highway Administration, Vehicle Travel Information System, 2008

Adoption, however, has not come. There’s only 867 electric heavy trucks have been deployed in the US. So why still the big deal? To understand this, you need to understand how exactly a semi truck gets used.

For the uninitiated, semi trucks are called that because they haul semi trailers, which have wheels in the back but not the front. The front is expected to be supported by the truck. Together the truck (aka tractor) and trailer are a vehicle built out of 2 modular parts which together make what we all know as a tractor-trailer.

Tractor and Trailer. Source: https://www.youtube.com/v=VPJ1biinnx8

On any given day, a tractor can encounter any number of different trailers. Flatbeds, tankers, dry vans, refrigerated trailers, the list goes on. All of these can be empty, loaded as much as possible, and anything in-between. The advantage of the modularity of the tractor and trailer is that any tractor can haul any trailer on the road. If the trailer was integrated into the truck, for example with a box truck, that equipment can only be used for one task. With a (diesel) tractor, you can haul any trailer you encounter.

With an EV truck, the added weight nullifies this flexibility. It still can haul any possible trailer type, but it cannot haul any possible trailer weight. What was a general purpose tool is now a special purpose tool. It has an asterisk always floating around it: *cannot haul heavy loads.

This has massive implications on the practical operations of a truck. What happens if you can only find loads that are too heavy for you to carry? What happens if the trailer you were hired to pull is loaded heavier than the bill-of-lading says? What happens is the trucker can’t haul the load, and a logistics headache begins for all parties involved. Day ruined.

But, what if there was a way to be electric when the weight permits, and then revert to diesel if the weight does not? This is exactly what we’ve built with the Revoy EV. When the GVW permits the extra weight of a battery, it hooks up like a trailer and electrifies the assembled vehicle. When a too-heavy trailer is encountered, the Revoy EV can be removed just as easily.

With Revoy, there is no asterisk. The semi tractor can remain a general purpose tool.

Modularity is the key

We leverage the fact that tractor trailers are modular vehicles, and just add another module. The Revoy EV even uses the exact same modular interface as the tractor-trailer. This means that it can be integrated with any semi truck on the road today, bringing quick and flexible electrification in a way that doesn’t ruin a truckers day.

Please reach out if you’d like to learn more! ian@revoy.com

--

--

Ian Rust
Ian Rust

Written by Ian Rust

CEO @ Revoy. Founding Engineer at Cruise Automation. Formerly Google X, Amazon Lab126, MIT.

No responses yet