Extended range electric cars with easily swapped battery trailers

While it’s understood electric car owners gain range confidence after a couple months of EV ownership, a question still lingers how an EV owner handles longer trips.   The easy alternatives are to either rent a gasoline powered car, buy a plug-in hybrid (like the Volt), or use a fast charging station.   Not too long ago Better Place was offering another alternative, rapid battery swapping, but that company fizzled out in a big way.  Now a company, eBuggy a.k.a. Nomadic Power, is talking of a different implementation of battery swapping:  Battery trailers.

The idea is pretty straight-forward.  You connect a small trailer to the car, the trailer carries a battery pack, and you connect that pack to the car.  The addon battery pack is easily swappable at a road-side service center, and would not require any expensive robotic equipment, nor require the car companies to conform their battery packs to a standardized pack shape.  It would require some cooperation among car makers on a charging port that doesn’t stop the car from running.

It’s really that simple, and conceptually every EV driver thinks up the same idea.  The difference between you, me, and them, is that these people have gone ahead and done it.

There is a huge gaping technical issue.  The existing charging port design locks the vehicle from being driven if the port is connected to a charging station.  That’s a safety feature meant to prevent drivers from driving off with the car plugged in.

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Nomadic Power’s trailer would have to connect to a DC charging port, and would have to negotiate between car and trailer about what voltage the trailer supplies to supply to the car.  This is similar to the negotiation that has to occur at a DC Fast Charging station.  But, again, the charging port would have to be configured so it doesn’t prevent the car from driving.

In use, you’d pull in at a battery trailer exchange station and an attendant would swap trailers for you and make sure to plug in the trailer you just dropped off.  Trailers being stored at an exchange station could be used for smart grid services, giving the company a second revenue stream with which they could reduce the cost of offering battery exchange services.

The Nomadic Power website claims their battery exchange stations would be very cheap to set up.  I imagine this’d be a little more complex than the propane tank services you see at many gasoline stations.  By comparison each Better Place station cost about $250,000 to build.

About David Herron

David Herron is a writer and software engineer living in Silicon Valley. He primarily writes about electric vehicles, clean energy systems, climate change, peak oil and related issues. When not writing he indulges in software projects and is sometimes employed as a software engineer. David has written for sites like PlugInCars and TorqueNews, and worked for companies like Sun Microsystems and Yahoo.

About David Herron

David Herron is a writer and software engineer living in Silicon Valley. He primarily writes about electric vehicles, clean energy systems, climate change, peak oil and related issues. When not writing he indulges in software projects and is sometimes employed as a software engineer. David has written for sites like PlugInCars and TorqueNews, and worked for companies like Sun Microsystems and Yahoo.

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