• Nov 2nd 2010 at 7:53PM
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EMAV PRU electric vehicle trailer – Click above for image gallery

The idea of putting some extra energy into a trailer that attaches to your all-electric vehicle when you need it is not a new one. Electric vehicle (EV) drivers have been designing their own for years, for example the EV Pusher, made by R. Sparks Scott, which took the front half of a 1978 Volkswagen Rabbit running on biodiesel and then pushed a 1981 VW Rabbit modified to be a pure electric vehicle. If you don't think the DIY method is for you, take a look at the PRU from new company Electric Motors and Vehicles Company (EMAV). PRU stands for Power Regeneration Unit, and it's a, "self-propelled electric vehicle power regeneration system that substantially extends the range of any electric vehicle." How this will work is not exactly spelled out in EMAV's press materials (or very odd website) but Wired provides the details.

The trailer connects to your EV through something called the Smart Hitch, a connector that can send, "a signal to the speed controller based on the pulling, tugging or tension that's delivered to the hitch when the host vehicle moves," EMAV founder and president Wil Cashen told Wired. The trailer has a 240V DC motor to propel itself, "so that the electric car never has to tow anything." The trailer holds some lithium-ion batteries and a four-cylinder, 750-cc diesel generator that, Cashen said, can provide 700 miles of range using six gallons of gas. The six-foot trailer can also hold some gear and is expected to cost $15,000. Ouch. A prototype PRU should be coming in early 2011 and production versions could be available in the second half of the year. The PRU is an expansion of the partnership EMAV has with Mopar to make and sell the Mopar - Jeep Off Road Camper/Trailer.

The PRU is not like having a Chevrolet Volt where you can take the range extender out when you don't need it. From what we can understand, the trailer doesn't charge an EV while driving – since today's EVs can't charge while driving anyway. The Nissan Leaf, for example, will not move if the charging cord is plugged in. Instead, the trailer is simply a way to recharge your EV when you're nowhere near an outlet. We think that Smart Hitch better lock the trailer to your car, because if you're toting around $15,000 on wheels, you don't want it cruising away while you're taking a break somewhere. Thanks to everyone who sent this in!

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[Source: EMAV, Wired, | Images: EMAV via Wired]


Electric Motors and Vehicles Company (EMAV) Launches with EV Range Extender
Automotive Technology Company Initiates Development of Proprietary Vehicle that Significantly Extends Current Range of Electric Vehicles

WAKARUSA, Ind., Nov 01, 2010 (BUSINESS WIRE) -- Electric Motors and Vehicles Company (EMAV), a global technology, product development and production company focused on rugged electric vehicles and electric vehicle technologies, today announced the expansion of its relationship with Mopar. EMAV will provide investigative R&D, design, and engineering for the EMAV PRU trailer, a patent-pending self-propelled electric vehicle power regeneration system that substantially extends the range of any electric vehicle. The introduction of the PRU follows the Mopar - Jeep Off Road Camper/Trailer series, the first vehicle line engineered, tested, and assembled by EMAV as a tier two supplier to Mopar; it is currently being sold through the Chrysler network of over 2,500 dealers in North America. EMAV intends to deliver further rugged tech products to the market in 2011.

The PRU ("Power Regeneration Unit") is an evolution of the Jeep Off Road Camper/Trailers, integrated with electric control technologies developed by EMAV. This new electric car range extender is expected to hit the market in the second half of 2011, with a running prototype scheduled for Q1 2011. The PRU will benefit owners of electric vehicles sold globally by making it possible to take an already capable electric vehicle on much longer trips, and enabling consumers to charge their electric vehicle where infrastructure does not yet exist. The PRU is intended to supply electric energy to any electric vehicle over the next ten years while the government and the transportation industry establish the necessary national electric vehicle charging station infrastructure.

"For electric cars to be truly viable for a mass consumer audience, we need to bridge the gap between low-range electric vehicles that can travel moderate distances to electric vehicles which can truly become the sole family vehicle," said Wil Cashen, founder and President, EMAV. "JD Power says that sales of electric vehicles will hit only two million in 2020 -- that is slow adoption, much due to the current range of these vehicles. Our goal is to move the marketplace beyond the first generation of electric vehicles to more powerful and rugged cars that also have endurance. This will evolve the electric car paradigm from a supplemental to a primary car for consumers."

Internally tasked with activating the lifestyle segment for Jeep as a tier two supplier, EMAV's Tech Camper/Trailers offer the rugged design elements popular with off-road vehicles such as Jeep. The EMAV Tech Camper/Trailers have been engineered and trail-tested over 300,000 miles, becoming the first camper/trailer to win the coveted Jeep "Trail Rated" badge. EMAV's Tech Camper/Trailers can be purchased in a number of designs to fit active lifestyles, such as camping, extreme off-roading, hunting, or fishing.

EMAV currently has patents pending for numerous electric vehicle power regeneration systems, vehicle electronics, and electric drive systems technologies, many of which are expected to be introduced to the global markets in late 2011. In the coming year EMAV will continue its strategic, incremental approach to product development with Mopar and through other new markets to introduce practical, common sense ideas that work. For more information, visit www.emavco.com.

About EMAV

ELECTRIC MOTORS AND VEHICLES COMPANY (EMAV) is a global technology and product development and production company focused on rugged electric vehicles and electric vehicle technologies. The company offers rugged camper sport trailers, electric power systems, and all-terrain vehicles of various models with power system options that include electric, hybrid electric, alternative fuel, gasoline, and diesel drive systems. EMAV provides essential research and development, engineering, design, production, warranty, and customer support for various automobile partners. EMAV is currently in development with numerous patent-pending electric vehicle technologies, including its proprietary Pru(TM): a power regeneration unit which extends the range of electric vehicles, expected to be available for sale in 2011. The company will continue to bring to market practical, common sense ideas that work.

Founded in 2010, EMAV is based in Wakarusa, Indiana, where its electric vehicles technology will benefit from the rich automotive tradition and skilled labor of the area. For more information, visit www.emavco.com

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    • 1 Second Ago
      • 4 Years Ago
      1Kw = 1.34048257373 hp

      20Kw = 26.8096514746 hp

      25hp engine = (Kubota E-TVCS V3300T diesel) 617 pounds (280kg)

      ST series 20Kw generator head = 385 pounds

      20Kw charger?

      Not gonna happen easily people....welcome to the real world.
        • 8 Months Ago
        Diesel fuel economy- turbocharged Kubota diesel from example

        .32 lbs fuel per horsepower per hour

        Diesel fuel mass – 7.3 pounds per 1.0 gallon (US)

        3.79 L per 1.0 US gallon

        1.0 pound = 0.455kg

        7.3 * 0.455 = 3.3215 / 3.79 = 0.876 kg/L (rounded off to 0.9kg/L)

        25hp * 0.32 = 8 pounds at full power to charge per hour

        8 hours to charge from fully discharged

        8 * 8 = 64 pounds for full charge

        64 pounds / 7.3 = 8.77 gallons (US) of fuel per charge cycle with diesel

        Battery life = 2500 cycles = 21,925 gallons of fuel burned over the life of the battery pack. 8 * 2500 = 20,000 hours charging at full power at 1800 engine RPM = 8 year service life expectancy with one full charging cycle per day

        Gasoline fuel economy-

        .485 lbs fuel per horsepower per hour

        Gasoline fuel mass – 6.216 pounds per gallon (US)

        3.79 L per 1.0 US gallon

        1.0 pound = 0.455kg

        6.2 * 0.455 = 2.821 / 3.79 = 0.744 kg/L (rounded off to 0.75kg/L)

        25 * 0.485 = 12.125 pounds at full power to charge per hour

        8 hours to charge from fully discharged

        12.125 * 8 = 97 pounds for full charge

        97 pounds / 6.2 = 15.65 gallons (US) of fuel per charge cycle with gasoline

        Battery life = 2500 cycles = 39,112 gallons of fuel burned over the life of the battery pack. 8 * 2500 = 20,000 hours charging at full power at 3600 engine RPM = 4 year service life expectancy with one full charging cycle per day


        1. To develop comparable power, the gasoline engine must turn twice the rpm of the diesel and be geared down to maintain 1800 shaft RPM on the generator head for 220VAc/60Hz power. The genset speed is fixed and CANNOT be altered.

        2. The gasoline engine has HALF the service life of the diesel engine, all other things being equal. This is being GENEROUS to the gasoline fuel engine.

        3. Only an IDIOT would use a gasoline engine to power a generator (i.e. there is NO manufacturer that builds a gasoline powered COMMERCIAL genset in the world. Gasoline gensets are proven to be fuel hogs and to have poor durability.)
        • 8 Months Ago
        Why would you use a heavy diesel??

        A motorcycle engine has been proven to work great at 35kw. AC Propulsion built one. The Long Ranger, Google it.

        It doesn't have to be expensive, heavy, or otherwise ridiculous.
        • 8 Months Ago
        Weight is the enemy in any project. At least TRY to keep on topic and in context of vehicles. I never said ANYTHING about a stationary genset.

        Fuel economy is not important??? Oh yeah, TRY to sell THAT idea when the numbers prove you have to spend hard earned money for 3x plus the amount of fuel to have your unreliable, fuel hog, POS gasoline engined genset.

        Reliability is not important? Tell that to the poor schmuck that bought one of your POS ideas that has failed after 2-300 hours and he still has to not only pay for repairs, but has to continue paying the loan off.

        I don't even know WHERE to start on your stupid comment about "high rpms and plenty of power". DO you have to practice to be so ignorant, or is it a talent you have for sticking your foot in your mouth while trying to impress the OTHER idiots on here? What part of my statement that you have to have 1800 shaft RPM on the generator head to produce electricity being FIXED and NOT ALTERABLE is not clear for you?

        Obviously you have never designed and integrated a package such as this in the real world of EV's. Please feel free to return to your world where the clouds are pink and green and everyone has everything they can ever imagine, no matter how unrealistic and ignorant.

        ....Some of us have to live in the real world of Earth, deal with physics and engineering, and STILL try to give value to the customer. It is obvious you don't....
        • 8 Months Ago
        Stationary gensets yes.... obviously.
        Because nobody cares about weight. And because they are expected to run nearly all day everyday, so durability is needed above all.

        But for mobile "range extending" of a midsize vehicle....

        1) Weight is the enemy
        2) Fuel economy is not as important
        * since this would only be used for occasional long distance trips in an EV when the rest of the year has seen amazing fuel economy *
        3) Durability is not as important since the typical trip is only a few hours long. And people won't be expected to use these gensets often.

        I understand your points. And believe me, I already know all about diesel's fuel economy and durability. I drive a VW TDI with 240k miles on it. And have been dependent on diesel 5kw and 10kw generators while in the field.

        But for "range extending" an EV... you need the portability and lightweight of gas engine. Perhaps even a wankel rotary. Yeah, I know the fuel economy is not great, and that the emissions aren't either. But they can fit in very small packages and provide high rpms and plenty of power for a generator.
      • 4 Years Ago
      And your compact suddenly has the footprint of a suburban.

        • 8 Months Ago
        For that one trip.
      • 4 Years Ago
      Ideally the answer is better batteries and I believe that will happen in time; however, I envision an interim solution based on a one wheel articulating trailer linked to the back frame of the car at two locations; this would cure any steering problem. The gen-set would charge the existing drive line batteries and the electonics would be hacked to start when the battery is 1/3 down and stop at full charge. I think a 220 AC generator would do the trick, tied into the charge port. Hey! if you run low on electricity, just park for awhile until the gen-set catches up. The trailer and gen-set needs to be as light and small as possible. This trailer much to large and heavy and is not what I see as the solution.
      I see the trailer as something like the following, only not as long:
      • 4 Years Ago
      This not a new thing at all. The TZero (which is what the Tesla Roadster really started from) had one. GM built them to power the EV1 in long drive tests.

      I think this is a great method have having EVs handle long distance on those occasional long trips.
      • 8 Months Ago
      • 4 Years Ago
      Really bad idea revisited occasionally.

      EVs will be mainly sold into multi-car households. So instead of going home and hooking up your expensive Range Extender trailer, just arrange to use one of your gas powered cars.

      The extremely smaller percentage of people that buy an EV in a single car household, RENT a car.

      This idea is a complete non starter.
        • 8 Months Ago
        This PRU will be cheaper to rent than another car. By the time these would be mass produced, the rental rate would be about half that of a midsize rental car.
        • 8 Months Ago
        Way before the marker becomes extensive enough to mass produce these there will be plenty of charging points to plug into when away.
        This would have a point if it could recharge the car whilst moving, but not if it only works when stationary.
        • 8 Months Ago

        First I said use one of your other cars.

        That will apply to 90%+ of EV buyers.

        For the small fringe of EV buyers, that don't have other cars, I would think they would prefer to just rent a regular car, which is likely not going to cost anymore because there is a ton of competition for car rentals, where this would be some kind of fringe portion of niche activity.

        Heck I would pay more just to not have to deal with the added aggravation of the trailer.

        Really this goes beyond bad idea, it is more in the category of loony ideas.
      • 4 Years Ago
      Its a bad idea in this incarnation. However, its a perfect space for all these alternative ICE configurations prove themselves.

      Wankel, linear ICEs, microturbines, DMFCs or what have you. If any of these can build a genset unit that fits in a trunk of an EV and provides ~20Kw output power, you have a winner.
      • 8 Months Ago
      So let me get this straight...If electric vehicles can't drive while plugged in, and if the vehicle senses it's plugged in when you're using this, this essentially makes this a towable stationary generator. To me, it would only make sense if it provided a steady trickle charge to main battery pack WHILE DRIVING! Otherwise...just buy a Volt. Am I missing something?
      • 8 Months Ago
      Did the OP author read the Wired article ?
      • 4 Years Ago
      $15,000?!! you could buy a brand new Honda Civic!!

      Only way this could work is if for example the owner of the Nissan LEAF use his 100 mile EV for city driving and for that occasional long trip RENT the Power Regeneration Unit.

      Anyways IMHO Better Place business model is better:
      *EV cheaper than petrol cars
      *unlimited driving range through 59 second battery swaps
      *batteries that are always fresh for the lifetime of the EV


        • 8 Months Ago
        Problem is, the EMAV PRU isn't really a "range extender", it's a self-propelled trailer that can be towed behind any vehicle, EV or not, without changing its fuel economy or driving range. It wouldn't actually increase the Leaf driving range, though It would add storage space. It's only real function is to carry more stuff, and it's rather expensive for such a limited role.

        An actual "range extender trailer" could work in one of 3 ways:
        1, As a generator trailer, providing electricity in a "series hybrid" way.
        2. As a "pusher" trailer, actually pushing the vehicle, though this might require a totally redesigned hitch arrangement and could adversely affect handling.
        3. A dual approach, providing both a push and electricity.

        Of course if the cost ends up too high, a range extender trailer becomes sort of impractical, as a rental or plug-in hybrid would be a better solution.
        • 8 Months Ago
        *No guarantee that you are not getting some abused battery
        *locked into a subscription with no way out
        *paying just as much as if you were buying gasoline


        Rent these PRUs for about half the price of a rental car.
        • 8 Months Ago
        "occasional long trip RENT the Power Regeneration Unit."

        Or just rent a gas powered car, so you don't have the waste of moving both a car and a trailer down the road.
      • 4 Years Ago
      This could be a good idea...if people didn't suck at driving. I don't trust 90% of drivers out there with a small 2-door, let alone one towing a trailer...the amount of accidents caused by improper merging would be astronomical.
      • 4 Years Ago
      Terrible idea.

      Way too much money for little to no benefit. Probably doesn't pass pollution standards. If it is a pusher trailer, then it is dangerous as it causes oversteer, especially in slippery conditions. Most of the extra power will be consumed with the extra drag.
        • 8 Months Ago
        It doesn't really "push", it's just self-propelled enough to eliminate any pull on the hitch, which means that all of its power is used to fight the drag it produces.
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