Ram Trucks boasts on its website that its 3.0-liter EcoDiesel-powered Ram 1500 pickup can, on a single tank of gas, travel as much as 728 miles. Similarly, Jeep’s Cherokee with the same engine manages 730. Volkswagen touts that its Passat TDI can achieve nearly 800 miles, and Chevrolet’s Cruze diesel can get about 717 miles when highway cruising.

These figures are, not surprisingly, cherry-picked from the best-case scenarios — that you’ll be achieving the maximum rating from the EPA (on the highway), using every drop of fuel available, and not towing or hauling any additional weight (so no cargo pods, trailers, or six kids in the back). But what these cars are doing — and it’s no coincidence that they’re all diesels — is pushing the boundaries of cruising range.

For many — most, really — cruising range isn’t something that we think about because we don’t need to. Gas stations are as pervasive as supermarkets (if not more so), so unless you’re looking at a seriously long haul, you’ll never really need to worry about whether you have 400, 500, or 700 miles on tap. But having that capability there is something manufacturers of gasoline engines can tout that makers of EVs, per se, cannot. It’s likely no accident that automakers are emphasizing this point to take advantage of the public’s general discomfort with not being able to get where they’ll need to go.

Electric cars, in this arena, have struggled. Your everyday, run-of-the-mill EV has struggled to break even the 100-mile threshold, and most tend to operate in the mid 80s — provided the same ideal conditions were applied. While this is largely suitable with about 80% of the daily driving done in the U.S., it’s makes for a tough sell when you have to tell consumers that they’ll need to stop and charge every 70 to 90 miles or so.

Tesla, though, has been able to handily outpace the pack, even since its early beginnings with the two-seater Roadster that first left the factory floor in 2008. The sports car originally boasted a 220 mile or so combined range, which blew other EV efforts to date out of the water. Even nearly seven years on, that’s still a commendable feat.

Tesla remains a leader in pure EV range with the Model S, which in its various trims can offer between 200 and 300 miles, roughly. This is considerably more in line with what buyers expect from a modern automobile but still shy of the 300, 400, and 500-plus mile ranges that those putting about with an internal combustion engine are used to. But as they say, where there’s a will there’s a way, and if any company has proven that it’s strong-willed, it’s Tesla.

Roadster upgrade will enable non-stop travel from LA to SF — almost 400 mile range. Details tmrw. Merry Christmas! — Elon Musk (@elonmusk) December 25, 2014

The company has developed a new replacement battery pack for the Roadsters that will allow the car to manage nearly 400 miles on the single charge. As CEO Elon Musk noted, that’s enough to carry a driver from San Francisco to Los Angeles without stopping, and the company will attempt to prove it possible by actually driving that specific route “in the early weeks of 2015,” it said.

The improvements aren’t solely related to the larger battery pack, though the added range largely is. The update comes as a package that also includes tweaked aerodynamic upgrades that can be retrofitted to the cars to make them more slippery, as well as new lower-resistance tires to help reduce drag.

“The original Roadster had a drag coefficient (Cd) of 0.36,” Tesla said. “Using modern computational methods we expect to make a 15% improvement, dropping the total Cd down to 0.31 with a retrofit aero kit.

“The original Roadster tires have a rolling resistance coefficient (Crr) of 11.0 kg/ton. New tires that we will use on the Roadster 3.0 have a Crr of roughly 8.9 kg/ton, about a 20% improvement. We are also making improvements in the wheel bearings and residual brake drag that further reduce overall rolling resistance of the car.”

As for the battery, Tesla notes that battery cell technology has improved considerably since the lithium-ion units were first implemented in the Roadsters. “We have identified a new cell that has 31% more energy than the original Roadster cell. Using this new cell we have created a battery pack that delivers roughly 70kWh in the same package as the original battery,” the company said.

This may not appear to be all that big of a deal — after all, Tesla only produced a couple of thousand Roadsters before phasing out the model in favor of the higher-volume Model S sedan. But like all major technological advancements, small trials have a way of extrapolating themselves before they become so commonplace in the consumer psyche that to the public, it feels like it’s been there all along. Carbon fiber, memory foam, and smoke detectors are all products that were developed for niche purposes that have grown to become everyday household items.

The point is this: The new Roadster battery packs are the beginning. Though Tesla doesn’t plan on offering an upgrade for its Model S in the near future, it has alluded that as battery technology progresses, the option will be made available, and this concept of being able to swap out your power source for an improved one is what makes the announcement such a big deal.

One can’t simply swap out an internal combustion engine for a more powerful, better model without the expertise to do so and a lot of finagling. But the magic in Tesla’s solution lies in its modular nature — the idea that owners can simply upgrade their vehicle as if they were swapping out the RAM on their computer.

This idea points to a larger, more forgiving future for EVs. As batteries get better, Tesla owners — and perhaps EV owners at large — have the possibility of updating their cars as the technology improves, rather than scrapping the whole vehicle for the latest model. Further, it indicates that Tesla has no desire to leave its previous buyers in the dark.

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