• Sep 8, 2010
Until now, one of the big downsides of battery electric vehicles (EVs) was the risk of running out of energy before getting back to a charging station. When an internal combustion vehicle runs dry, a driver can always call roadside assistance to bring some fuel or just hike to a station and bring back a can of gas or diesel. Under the same circumstances, an EV would require a tow to an outlet somewhere.
A research team led by Zafer Sahinoglu at the Mitsubishi Electric Research Laboratories in Cambridge, MA is developing a system of portable chargers that could be deployed to locations where EVs run low. The plan would be to equip electric vehicles with live telemetry that transmits battery state of charge and location information to a central server. The portable charging stations would likely be a giant battery pack on wheels that would be charged at a central depot and then sent to wherever EVs need replenishment. Supposedly, five mobile units could cover 100 EVs on a 60-mile stretch of highway. Sahinoglu is presenting his concept at the Vehicular Technology Conference in Ottawa, Canada, this week.

[Source: New Scientist]


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    • 1 Second Ago
  • 18 Comments
      • 4 Years Ago
      Batteries have poor energy density and high cost. Wouldn't it make more sense to just have a little gasoline powered generator?

      I have a Yamaha generator that isn't that large and can plug into my house, so it sure as heck can charge an EV. Runs pretty quiet too thanks to advances in compact muffler technology.
        • 2 Hours Ago
        Ever camped near a motorhome that was recharging the house battery using a generator? Ever feel the urge to kill the owner as the thing droned on and on for several hours? That's why you emergency recharges won't be by a gas generator.

        Those small, very portable generators put out 1000-2000 watts, you'll be along time charging an EV battery.
        • 2 Hours Ago
        If you go for full battery. That 2000W is enough for 10 miles with max range mode in one hour.

        Anyway using high power density batteries you can get that with less than 30kg battery in _way_ less than hour.

        Batteries like is used in MotoCzysz ( http://www.motoczysz.com/main.php?area=edd_overview).

        Only two of those 8kg batteries holds 2.5 kWh energy and you can get around 10 kW power out of it. It would take only 10 minutes to charge that 2.5kWh that is needed for 10-20 miles (10 for around 50mph, 20 with max range).
      • 2 Hours Ago
      yeah, why not a lean onboard generator or even a super tiny limp emergency generator. a 150cc 1-cylinder weighing very little could push for instance a carbon BMW at 130km/h (81mph) max or comfortably at 100km/h. should be plenty for an emergency..

      could be a little module you could install as an option. my guess is most would buy that.
      • 2 Hours Ago
      Just a thought:

      I believe these "recharge cars" would need to serve more RE-EV:s than pure BEV:s. ICE is breaking-prone tech (just too many moving parts), so those cars that exceeds pure battery range with broken RE gets surprise stop. Driver can't predict that and can't plan his driving accordingly. For example Volt with 80mile trip, you reach 40miles and RE should start, but is broken (fuel pump broken or something). There you are, 40 miles from destination and 40 miles from beginning of the trip with no charge left to get you anywhere.

      Pure BEV has nearly nothing to break, and car charge meter should alert the driver that there is not enough juice left before you even start the trip. Nice thing with pure electric drivetrain is that you can predict what will happen pretty accurately.
      • 2 Hours Ago
      If you go for full battery. That 2000W is enough for 10 miles with max range mode in one hour.

      Anyway using high power density batteries you can get that with less than 30kg battery in _way_ less than hour.

      Batteries like is used in MotoCzysz ( http://www.motoczysz.com/main.php?area=edd_overview).

      Only two of those 8kg batteries holds 2.5 kWh energy and you can get around 10 kW power out of it. It would take only 10 minutes to charge that 2.5kWh that is needed for 10-20 miles (10 for around 50mph, 20 with max range).
        • 2 Hours Ago
        duplicate. This was meant to be reply to Jim near top of the page.
      • 2 Hours Ago
      A decent sized generator connected to the PTO drive or hydraulics of any typical flat-bed tow truck could generate plenty of charge to get people that extra 10 miles needed to get to a charger. Flatbed anything further away, since you must have been crazy to be off on your range calculations by more than 10 miles. The latest diesel engines that tow trucks often use are putting out 350-400 hp, and over 700 ft/lb of torque.

      http://www.autoblog.com/2010/03/10/gm-quickly-one-ups-ford-with-2011-duramax-diesel-ratings-releas/

      That can produce a huge amount of electricity in a small amount of time when connected to the right generator, and there wouldn't be any need for a specialized fleet of EV-charging vehicles. And since these trucks already have the engine half of an electrical generator, there is no reason to carry a full generator with it's own engine/gas tank/etc...
        • 2 Hours Ago
        A generator hanging of the PTO of tow trucks is what you will see, simplest and cheapest solution.

        The Coda can take up to 6.6kw, both the LEAF and Volt are limited to 3.3kw.. if you are lucky enough to have the fast charge connector on your LEAF (and paid for it, it costs extra) they can pump in 50kw.. thats the one that does 80 miles of range in 30 minutes.

        There ought to be a law that every BEV have this fast charge port available.. perhaps under the hood or in the trunk. It may not cost much if kept simple.
      • 2 Hours Ago
      Wrong approach: Put the GENSET in a trailer and start charging the battery when you start out so you can charge the battery along the way. Based on the data of charging at 220volts ac that should give you about 150 miles range on a 2 hour journey. Then when you stop for about 4 hours you can start out again. With this approach, you wouldn't need to buy electrons from charging stations... yes, there are problems to solve if you do this, i.e, hacking into the control electronic, building a single wheel trailer, etc. But these are fairly easy to solve.
      • 2 Hours Ago
      I got a better idea, dont sell EVs to stupid people that can't plan a damn thing.
      • 4 Years Ago
      Five chargers are required to support 100 EVs? Seems pessimistic to think that 1 out of 20 EVs will go dead on the road.
        • 2 Hours Ago
        Yeah, I don't properly understand what they are talking about, and was hoping that someone would post and enlighten me.
        It seems as though they are saying that 5 of these chargers would be sufficient to top up 100 cars which had run low, but it is not clear if the charger goes to the car, or vice versa.
        5 of these to cover 60 miles of highway sounds a heck of a lot too.

        I've still really not got any clear idea of what they are talking about, and Googling did not help.
      • 4 Years Ago
      Having a standardized DC quick charge port for EVs would be very useful for use in emergency situations like this.

      Yes, a gas-powered generator works but it would take hours. If one could quickly provide a charge that would give the EV 10 miles or so, that would remove a great fear about EVs. Running out of charge is not really the big problem . . . we run out of gas with gas cars too. The problem is the fact that you can't quickly recharge. Pouring a gallon of gas into a car quickly solves the running out of gas problem but there is no equivalent for EVs.
        • 2 Hours Ago
        For ten miles you would only need about....

        (Roadster figures)
        60mph at 15kW = 15kWh for 60miles = 2.5kWh for 10 miles. Nearly half that for max range mode.

        20-30 kg high power density battery. Can literally be carried, no need to have huge generators or stuff like that. You only need DC charger to add. For that amount of weight you could use electric bicycle to serve that 60 mile stretch.

        • 2 Hours Ago
        @Ducman69
        In your example of using a typical portable generator, you have to go through the 110V/220V charger inside your EV. In most cases, this charger has very limited power (for example 3.3kW in the Leaf). If your portable generator had DC capability, then this will help somewhat, but you are still limited by the power output of the portable generator (typically very small, the most powerful Yahama generator I could find is 12kW, which will take 2-3 hours to fill the Leaf).

        However, with a direct DC connection and a second larger battery pack, you can do a very quick charge akin to a level 3 charge (the DC charging stations that can charge the Leaf 80% in under 30 minutes). Then the limit is truly only the power limit of the battery pack inside your car.

        I think what you are thinking of is the use of a high powered ICE coupled to a powerful electric motor/generator as the source of power, like in the Volt, but that isn't what comes to mind usually when we think of generators.

        The portable generator is more applicable to the case where you pull it along and it provides you with power to maintain speed (for example long distance highway cruising on a roadtrip).
        • 2 Hours Ago
        Why would a gas engine producing electricity charge at a slower rate than an electric battery releasing electricity? o_O

        Clearly the limitation here is how many amps the battery in the car can take for charging.
      • 2 Hours Ago
      I think you guys are missing the point.
      Unless the car is operated locally with a very limited range, charging is not the answer.
      To open the horizon for Ev's we need to look at standardized replaceable battery modules. These would be replaced at refueling stations, where they would be recharged and ready for the next customer. Much like what is now being done in the propane business.
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