Rapid Charging Electric Cars: How Fast, How Soon?


Before unveiling the concept version of its Model S sedan, an $57,400 electric car that Tesla Motors wants to build using loans from the Department of Energy, the startup said the Model S battery would be designed to handle rapid charging. Last week, at the Model S unveiling in Los Angeles, Tesla revealed that an optional “QuickCharge” battery would get a full charge in 45 minutes from a 480V outlet. For the standard version, Tesla plans to use a battery that can recharge at a typical 220V outlet in about four hours.

While the Model S is in the concept phase of development, rapid charging represents a very real focus for battery developers and electric car makers. Nissan is working on an electric car that it says is on track to have a 100-mile range and 26-minute charge time. Earlier this month, researchers from MIT said they had developed a process that within three years could lead to electric car batteries able to recharge in as little as five minutes. How quickly can we really expect the early generations of electric vehicles to recharge — and what does it mean for the practicality of EVs?

I asked Mike Omotoso, J.D. Power & Associates’ alternative powertrain specialist for North America, how realistic it would be for a driver to charge up at a 480V outlet during a long road trip. “A 480V outlet is a little unusual,” used mostly for higher-power industrial applications, Omotoso said. While some airports have 440V fast-charging stations, he said, a typical U.S outlet is 120V. We use 220-240V outlets for large home appliances like ovens, furnaces and clothes dryers.

The higher the voltage, the shorter the charging time — but not without a tradeoff. “It is also more dangerous to have higher voltage,” Omotoso explained. “Buyers of the Model S can play it safe (and have more flexibility in terms of where they can charge the car) by using the standard 120V outlet, but the charging will take longer.”

Since rapid charge times come on the condition of available outlets, higher-voltage charging infrastructure would need to be put in place — built over the course of years — to facilitate the charge times some automakers are shooting for. The Renault-Nissan Alliance launched a pilot project in Arizona earlier this month to test out a charging network ahead of the planned 2010 launch of its electric vehicle.

EV infrastructure startup Better Place, on the other hand, which has several countries on board with its plan to build large-scale networks of battery swap stations and charge points, has a different plan. The company says its charge spots would have voltage on par with standard household outlets. For on-the-go juice ups, the idea is to exchange your dead battery for a fresh one owned by Better Place.

Extended-range electric vehicles — such as the Chevy Volt, which GM says will recharge in three hours — offer another route, adding a small gas engine to keep drivers from feeling stranded without access to fuel. Which scheme wins may depend (in addition to financing hurdles) as much on our driving habits and patience as on advances in technology. How long would you be willing to wait for an electric car to recharge, and how much range would you need to have to feel secure hitting the road in an all-electric car?



440V AC dangerous? Only to people dumb enough to stick their fingers in sockets. It’s FAR more dangerous trusting the public to deal with a gasoline pumps.

Don’t worry about it. Electrical safety can be engineered in whatever voltage is used.

Ultra fast-charge stations would work better for me than swapping batteries. Why? Battery swapping requires standardized batteries which will freeze design progress.


Rapid charging is so easy you’ll all fall over and laugh about this debate once charge points start to get installed. 99.99% of the infrastructure is already there connected to every building and running down every steet.

The reality is there is pretty much no NEED to have a 5 min rapid charger at any residential address, because an EV has all night to charge at home. So it will be commercial locations that install rapid chargers for EV drivers away from their home in need of a top up and in most cases these locations already have 480v 3 phase installed.

It’s all too easy… and about 1/1,000,000 th the effort of installing a hydrogen infrastructure from scratch!


@bob gee
I don’t know where you got 157 miles. The Roadster can go 244 miles EPA. The old number was 221. That means typical range is at least 200 miles per charge.

The battery pack has a capacity of 56kWh. At 80% charging efficiency that’s 70kWh. Divide it by 200 miles and I get 350Wh/mi. Then I get 5.6 cents per mile which puts it exactly at your Civic’s cost @ $1.94 per gallon.

Gasoline prices change fairly rapidly. Just last year the story would have been completely different, so it’s hard to say which is worst, the electricity price’s dependence on usage or the volatile gasoline prices. However, further down the line I think gas prices will rise much higher than electricity prices just because electricity sources are much more diverse.

The expensive batteries are definitely a concern, but I think battery prices (in relation to capacity) are still heading down (~5% / year in commodity cells, the more advanced cells don’t seem to be getting cheaper yet but they aren’t made in large volumes yet). $14k for a 56kWh pack is already a good price even for costs. A typical EV can do with a smaller 35kWh pack for 100+ miles of range which is $9k. That’s not too bad, if battery prices keep going down, then a BEV-100 of near cost parity (referring to same size of car) becomes possible. Tesla’s goal of releasing a $30k car seems like it should be achievable in a few years (I’m waiting for that one, looking for a $30k EV, 5 door hatch preferred, size around the Civic, and must pass crash tests). EVs don’t have to be small or impractical, the Tesla Model S is a great example.

Only in the backdrop of the economy it might seem like the money is better spent elsewhere, but since the funds were specifically set aside for advanced technology vehicles I think Tesla deserves as much a chance at it as the other company applying for the money. Also hopefully by the end of 2011 (when the Model S car is due) our economy has recovered somewhat. EVs are as good as a technology as any of the others to support. PHEVs/EREVs can fill the gap and provide a cheaper alternative to BEVs until battery prices decline enough to take out the ICE. The only other similar alternative is hydrogen and the economics on those cars are even worst so far.

bob gee

Without accessories running, the Tesla Roadster consumes 275 Wh/mi of energy from a battery. While government data suggests the retail price of electricity is somewhere around 10 cents per KWH, the addition of taxes and fees puts the price somewhere aorund 16 cents per KWH on my electric bill. The price goes up with demand and usage.

With accessories running, the Tesla Roadster will consume around 350 Wh/mi from the battery, but it takes about 440 Wh from the electric company to provide the 350 Wh per mile because of losses in the charging process. That’s 7 cents worth of electricity per mile driven. With a 55KWH battery, range is only 157 miles.

My Honda Civic averages 34+ MPG over a year period. At $1.94 a gallon , that’s 5.7 cents a a mile, 1.3 cents per mile cheaper than driving an EV of similar wieght.

The thing that bothers me the most about Tesla is not the range or cost of driving an EV. It’s that Elon Musk might risk $350 million US taxpayer dollars on something that will end up costing consumers more money. The taxpayers gain absolutely nothing, not even a stake in the company, just the risk. Why should my hard earned money go to support his hobby?

Lithium battery pricing is currently projected to drop to $1 per KWH by the end of 2009. Ultimately, some believe a cost, not price, of $0.25 might be achievable. That’s still at least a $13,750 per electric vehicle cost for a range of 157 miles in a very small, impractical vehicle, using the most optimistic projection. It gets worse in a larger vehicle.

With our current economy, I guess it’s no longer a secret that politicians and executives running our country are not very good at simple math. Maybe throwing more money away is expected. Elon Musk is going to get about $5 of my hard earned money based on my fair share of taxes. I should at least own $5 worth of Tesla in return.

I’m depressed.


This is definitely the biggest hurtle that EVs have in my mind. My parents live about 180 miles away, which is well outside the range of most electric cars. If I’d have to plan on stopping somewhere for an hour in the middle of a 3 hour drive, just to refuel, I’d feel pretty compelled to stick with a gasoline/diesel vehicle.

And even if a car’s range is 100 miles, on a day where there is a strong headwind, I’d probably have to stop twice to recharge. That’s a deal breaker for me.


I don’t want to wait for my car to charge. I want to plug it in when I’m doing other things, be it at home or at the mall.

Charging should be passive, not only charging when the battery is completely dead, but constantly keeping your battery topped off by charging little bits, everywhere your park.

For longer trips, when in-between (active) charging is necessary, the maximum acceptable waiting time would be 20-30 minutes for me.

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