EV does 2,500 miles between charges

How far can an electric car go between recharges? Fifty miles? A hundred? Two hundred?

How about nearly 2,500 miles? At least, that's the aim of a team from the universities of California and Carnegie, who next year plan to drive an electric VW Golf (like the one pictured) the entire width of the United States in under 60 hours - 2,470 miles from San Diego to South Carolina - without once plugging into the mains. What now?

Here's how it works. The modified 2002 Golf's e-motor runs on a set of 18 briefcase-sized battery modules. These can be individually popped from the VW's boot, and replaced with ‘fresh' modules, meaning it never has to be directly wired to the mains.

The project aims to demonstrate the team's recently developed Modular Battery Exchange and Active Management System (M-BEAM).

Though it might seem something of a cheaty solution to the electric range project (after all, the batteries will still have to be plugged in somewhere, just not while attached to the car), the M-BEAM system is actually a nifty piece of work. Most electric cars that run from more than a single battery will slowly deplete all at once, thus requiring a full recharge of all batteries when they're out of juice.

But the M-BEAM system depletes its batteries in sequence, allowing the driver to swap out ‘dead' batteries and continue driving, without stopping and waiting for the car to fully charge again.

There are a few downsides, though. Mass, for one. Each of the 18 batteries weighs between nine and 14kg, adding a couple of hundred kilos to the Golf's kerb weight. The sheer volume of the batteries in the boot doesn't leave a whole lot of space for other stuff, either.

And then, of course, there's the minor issue of requiring a support truck to follow you with a suite of recharged batteries. It's fair to say that this isn't, for the most of us, a practical solution to the range anxiety surrounding electric cars.

However, the team reckons the information gleaned on its Trans-Am voyage should help, in the long term, reduce the cost of batteries and charging tech. The study estimates an average drop of $10,000 (around £6,000) in price for electric vehicles in the near future, thanks to reduced battery costs.

And, as we discovered when attempting to drive a (normal, petrol-powered) Focus ST across the States without using interstates, any flat-out Trans-Am trip presents a challenge. From coast to coast in just 60 hours in an EV will be grueling. Brave battery voyagers, TG wishes you luck.