• Oct 10th 2008 at 11:01AM
  • 29
Click above for more high-res shots of the eRUF Model A Concept

Rumors of RUF's impending electric Porsche were true, except that the actual vehicle is based on a Porsche 911, not the Cayman as previously reported. Powered by a three-phase electric motor that offers about 200 horsepower along with an impressive 480 lb.-ft. of torque, the eRUF Model A can reportedly hit 60 miles per hour in under seven seconds and can reach a top speed of 160. Power comes from a lithium iron phosphate battery pack, which produces 317-volts and 480-amps and is made up from 96 individual cells. A full charge takes a rather long 10-hours, and regenerative braking is included in the package allowing for a range of up to 180 miles. From the outside, you'd never really know that something was different about this 997, except that it doesn't produce that soul-stirring flat-six sound. This is still just a concept and its specifications are subject to change. We can be sure, though, that this isn't the last electrically-powered sportscar set to hit the market.

[Source: RUF]


eRUF Concept Model A 2008

" Emotion without Emission"

Ruf Automobile GmbH, internationally well known manufacturer for high performance
automobiles and the producer of the famous CTR-series is now introducing the first
electrically powered sports car from Germany.

The fundamental ideas that lead to the development of the eRUF concept vehicle came from
Alois Ruf. The car maker from the Bavarian town of Pfaffenhausen had a vision of a simple
energy transfer concept: his hydroelectric power plants, which feed 35 million kW hours of
electricity annually into the German electrical network, could also more or less directly power
modern autos. 35 million kWh is enough energy to power one of the prototypes eRUF as
described below for 3500 journeys around the globe – or 3500 of the cars one time around the
world each.

The idea seemed even more inspiring, as it would be possible for him to connect cars directly
to the emission-free power plants for charging and drive away on the water-generated power.
The eRUF Model A concept car is the first prototype to lead the technical development away
from the combustion engine.

Actually, for the first time an electric motor is being used which comes to fitting into the Ruf
model range.

The three-phase AC motor's performance easily puts many conventional conbustion engines
to shame. It produces its maximum 650 Nm torque output from 0 rpm onwards. This power
rips into the drive shafts so impressively during acceleration, that one is immediately
reminded of the extremely powerful Ruf Rt 12

It is actually enough simply to put the car in 6th gear and press down the accelerator pedal (an
"amp pedal", not a "gas pedal" in this car!), and drive off.
The eRUF Model A has such impressive acceleration that the project goal of 0-100 km/h in
under 7 seconds was achieved.

The maximum power output is around 204 hp if you translate it into combustion engine terms.
In direct connection to Volt and Ampere the maximum output level of 150 kW is a useful

A short discourse regarding efficiency might be helpful at this point: a highly-developed,
modern petrol engine uses around 75 percent of the energy in its tank to heat the engine
coolant and exhaust gas and only 25 to 30 per cent for actual propulsion. A diesel manages to
convert a respectable 35 to 40 percent of its fuel energy into motion. The permanent magnet
electric motor, on the other hand, is a model of high efficiency: it offers over 80 percent
efficiency over the majority of its power range, extending 90 per cent in the upper end of its
power range.

Ruf engaged CALMOTORS in Camarillo, California, specialized in the implementation of
hybrid electric and electric only power train designed to combine the latest generation of
lithium-ion batteries with its motor.

Since the 150 kW electric motor unit is very compact, there is a lot of room for batteries in the
Ruf's bodywork.

The Axeon iron-phosphate, lithium-ion batteries currently in use weight 5.6 kg and deliver
160 Ah each. This means each one could theoretically deliver 160 amperes of electricity for
one hour under normal temperatures or 1 ampere for 160 hours.

The generation of batteries available from Axeon represents by no means the end of the
developmental curve. Current performance improvements in battery technology indicate that
end of this improvement spiral is nowhere near.

The driving current in the eRUF is regulated by an electric "drive-by-wire" accelerator pedal.
It is not the first electrical accelerator in a Ruf model. Other Ruf models also provided load
control via potentiometer-pedals, nicely dosed for their powerful engines.
The power and torque produced by the 3-phase motor can be used to recover just as much
power as it can put out. When coasting, the motor becomes a generator producing electricity
to charge the batteries. The torque and electrical amperage ratings below are therefore to be
understood as theoretical absolute maximums and minimums.

The 96-cell battery system is constantly monitored by an intelligent bus system from Axeon.
Each individual cell is coupled with a sensor that sends critical information on cell
temperature and voltage to the central control system. If irregularities appear during
operation, the system can react within milliseconds to bring the values back in line,
effectively preventing critical lithium-ion overheating behaviour during charging.

Tech specs for the eRUF model A, status of September 2008
All data are preliminary data as specified for the eRUF Model A

Drive Performance
· Acceleration 0-60 mph under 7.0 sec (development target)
· Vmax 160 mph, 225 km/h
· Cw 0.28
· Roll resistance 0.014
· Driving range approximately 250 – 320 km, depending on
performance level
· Specific power pick-up 21 kW / 125 km/h

Vehicle data
· Engine power 150 kW / 204 PS
· Max torque 650 Nm 7 0 rpm
· Weight 1910 kg (preliminary data)
· Battery weight 550 kg

Motor Data
· Max torque + 650 Nm to -650 Nm
· Power + 150 kW to -150 kW (peak level)
+ 204 hp to -204 hp
100 kW / 136 hp continuous
· Currency 300 – 420 Volt
· Current level max 550 A
· Rpm level max 5000 rpm
· Operating system brushless three phase alternating current with
permanent magnets

· Diameter 405 mm
· Length 241 mm
· Weight 91 kg
· Specific weight 1,65 kW / kg, 2,25 hp / kg
· Coolant flow 8 L /min max

Battery System
· Type Lithium-Ion, iron-phosphate base
· Manufacturer Axeon plc, GB
· Stored Energy (96 units) 50,72 kWh
· Nominal Voltage 317 Volt
· Maximum discharge 480 A
· Max Power 152,16 kW = 210 PS
· Charging current, max. 16 A
· Charging time 10 hours

Single Battery Cell Data
· Capacity 160 Ah
· Operating voltage 4,25 V charging, 2,5 Volt discharging
· Nominal Voltage 3,3 Volt
· Max. Temperature Level 80 °C
· Life cycle 3000 charging cycles
· Self-discharge under 3 % per month
· Weight per Unit 5,6 kg

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    • 1 Second Ago
      • 6 Years Ago
      Great concept. I hope something like this comes to market as soon as possible.
      • 6 Years Ago
      Too bad the shell is based off the 997, thats a lot heavier of a body than would be ideal for this powertrain.

      Maybe the composite fiends over at 9FF could team up with Ruf to make something thats a good 1000 lbs lighter?

      Looks nice however, all aero like a Gmund Roadster or 356 Speedster.
      • 6 Years Ago
      To Brandon,

      If you want a PORSCHE that is great, but this is a RUF not a PORSCHE.
      • 6 Years Ago
      ruf should tell us how many miles it'll go around a track
        • 6 Years Ago

        An excellent read about a subaru twin-AC-motor electric race car, "Electric Imp". Read the full specs here:

        They got about 0.9 kWHr per mile during race running at 387V / 300A, with regenerative braking limited to 200A (to keep the motors cool). Full-current regenerative braking recovers nearly 18% of their kinetic energy, they were recovering 8% with friction brake use, or 12% normally.

        Note that their battery pack is nominally rated for 36 kwhr, it started to sharply drop after 29kwhr on the final lap (14) of their 2.25 mile course due to high current draw.

        With the RUF's 51kwhr (nominal) pack, you could probably get 45-46 miles in full-out race mode assuming efficiencies are similar to the Imp. It's a heavier car (4200 lbs - is why the 0-60 is so slow :), but it may be able to use full regenerative braking.
      • 6 Years Ago

      Lol...this is a really nice idea, but I'd never buy it... if I'm buying a Porsche, I want a PORSCHE.
      • 6 Years Ago
      I presume you mean Lithium ION, rather than IRON.
      • 6 Years Ago
      A Porsche powered by batteries alone is not a Porsche. It is a car that looks just like a Porsche, but it is not a Porsche.
        • 6 Years Ago
        Just a friendly reminder - Dr. Porsche was a brillant engineer who would be proud to see electric Porches on the roads. The link goes to an early Porsche hybrid...

        • 6 Years Ago
        @ Bill: +1, though I'd change it to "a Porsche powered by batteries either as a hybrid or a pure electric vehicle is not a Porsche"
        • 6 Years Ago
        I remember Hence Ruf. He used to live behind me when I was growing up in California. He was a little weird and liked to hang out at windshield replacement shops so he could sniff the weather stripping glue when no one was looking. Last I heard Hence was an elected official in good standing in California who still likes to sniff glue between bad ideas.
        • 6 Years Ago
        Hence RUF
      • 6 Years Ago
      If memory serves Ferdinand Porsche designed military transport vehicles that were full electric. This was well before WWII. I am guessing they were used during WWI , but I could be wrong since I am lazy enough today to not look it up.
      • 6 Years Ago
      What a waste of a gorgeous car.
        • 6 Years Ago
        0-60 in 6.something is pretty damn slow in my book, at least for a new/newer car, but regardless, my comment wasn't directed at the car's performance; it was directed at the power source the car now uses to achieve it.
        • 6 Years Ago
        0-60 in under 7 seconds isn't exactly sluggish.
        • 6 Years Ago
        We have a guy at my work that has a home built electric '88 MR2. It does not have much range (20 miles i think) but it was built on the cheap and will hit 60 in the 5 second range. If youre going to make an electric out of a porsche, it should be faster than that. Seriously people we dont need 180 mile range on an electric initially. Just 50 mile is sufficient as a commuter. With regenerative braking im sure that greatly improves city range. And with less range the charge time would be a more reasonable 4-5 hours.

        Personally what we need it corporations to provide the charging for employees while they are at work. Give the employees free electricity, and give the company a tax credit, and suddenly our electric cars only need half the range for comuting. Which means less batteries and means less up front automobile expense.
      • 6 Years Ago
      Somebody wake me up when the electric car craze is over.
      • 6 Years Ago
      this car needs work better performance is needed that is all!!
      • 6 Years Ago
      What's a Lithium IRON battery??
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