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Mitsubishi and TEPCO Testing Latest Version of i MiEV Electric Car

The current i MiEV.

Mitsubishi Motors Corp. and Tokyo Electric Power Co. (TEPCO) have begun test-driving the latest version of the i MiEV electric car. Mitsubishi delivered its first prototype to TEPCO in March 2007. (Earlier post.) The two have been collaborating on the electric vehicle since 2005. (Earlier post.)

The latest prototype has a newly developed lithium-ion battery, a more efficient motor that is also 10% lighter, an inverter that is 30% smaller, and tires that rotate with less resistance.

The expected range on the new version is now 160 km (100 miles) with the 16 kWh battery pack—a 23% increase (30 km) over the first prototype. The earlier version required the use of a 20 kWh pack to achieve the 160km distance.

Total distance accumulated during the first phase of testing was about 4,500 km (2,796 miles)—sufficient, according to the partners for an initial check on the fast charging and the integrity and suitability of vehicle operations (range, power performance, ease of use, etc.)

Mitsubishi Motors has supplied 10 of these new models to Tepco. This phase of the testing will run through March 2009, during which Tepco will collect data for Mitsubishi’s evaluation, and evaluate charging and driving performance.



IMO, the 4-passenger iMiEV is the most practical example of a close-to-production (and hopefully close-to-sales-in-North-America) vehicle. Can it be improved? Certainly - for example, instead of aluminum, use carbon fiber (using Fiberforge techniques) as a unibody material. But it is a heck of a start. I will buy one as soon as it is available in the US.


@Tom Street:

Where do your numbers come from? I thought the official Prius CO2 emissions were 104 g/km = 167 g/mi. Do you also factor in the refinery emissions? Or is it based on real life fuel consumption?

The CO2/kWh for power plants does that include grid losses? I also assume that to fully charge a 16 kWh battery, you usually need to put in more than 16 kWh of electricity.

Just to clarify - the 'official' Prius emissions only account for the CO2 from the gasoline in the tank. There is no accounting for all of the CO2 produced in the exploration, drilling, extraction, refining and transportation of the gasoline to the tank. I think probably the electrical CO2 per kWh estimates are closer to the truth than the 'official' gasoline CO2 figures.

Tom Street


I got the 210 figure from a previous post I made. I no longer have figures that went into that. However, the IPCC estimate of co2 emissions per gallon of gasoline is 8788 grams. Using the current (revised) EPA estimate of 46 miles per gallon yields of grams/mile figure of 191.

I didn't use a grid loss factor. Do you have that factor? If so, I would be interested in seeing the results based on that factor.

In any event, it appears that this EV would still beat a Prius even with grid loss. And, as pointed out above, there are also all the refining, research, drilling, and production factors to consider.


EVs are great and 10% of the cars being EV would maybe be even better that 10% hybrid. With 10% hybrid and 10% EV, we are on our way to reducing oil imports and cleaning up the air.

I hope that they keep making advances in batteries. If we could have 100 mile range with small, lightweight batteries that cost a few thousand dollars and last more than 10 years/100,000 miles, they would be very popular. So far, I have not seen any of these in wide spread production/mass consumer usage.



A quick search on Wikipedia for grid losses yields a figure of around 7%.

I think the revised EPA estimate is pretty close to average real world consumption for the Prius. Add to that a figure of around 30% well-to-pump CO2 and a good well-to -wheel CO2 estimate for the Prius would be 250 g/mi.

Even when adding the 7% grid losses, and a real world usage that is 20% less efficient than the 10 m.p.kWh that Mitsubishi claims, it is still better by nearly a factor of 2.


Wonder what the price will be...

Just a guess- say $30,000 MSRP minus a $4,000 Federal Tax credit.

I'd be willing to spend $26,000 on this vehicle given a 200 mile all-electric range.


I see alot of wrong info so ill try and clear it up.

1 A battery is never perfect.. at best at best temp charge rate and charge range your talking about 80% AND that isnt even outlet to bat thats just the bat itself. On TOP of that just as in your computer there is a power supply converting ac to dc and regulating it and all.. and those are never perfect.. most computer ones are only 50-65% eff and the best are 85-90%.

Grid losses varry.. in california they are high.. right next to diablo nuke plant however its nill;/

To make matters worse they extend range by widening the charge range faaar past its efficient range and thus the battery heats up alot more wasting far more power on charge up AND they charge it faster AND they let it get hotter.. all fubarring recharge eff.

Add in the losses due to cold or hot weather.. below x your bat looses MOST of its capacity and wastes more power to charge and too hot and...

And THEN we have battery leakage.. ever recharged a lith battery then waited an hour or 3 and tried to charge it some more?

2 This car has no room for both a battery and a small engine and gas tank its simply too small to fit it all in. Its that small because even a 16kwh battery cant prvide the energy just half a kilo of j2 could.. between 7-9 kwh usable energy.

As with biofuels and h2 and everything else.. in the end we will only truely know if we didnt screw up after we screw up BIG..

Bob Bastard



Subaru is also testing this kind of EV in Japan.
Their target MSRP is less than 2M yen(less than US$19,000).


If your talking about my posr bob.. wrong. The bat makers themselves have the specs for all this info snf msny car makers are showing said info.

Oh and how big is your hiney? Because as a friend found out its rather hard to ise a stick shift if your sitting on it and many of these cars have very narrow seats.

Susan K

Parking meters already have electricity run to them - we could easily add daytime charge-up stations to parking meters.

Bob Bastard

Nonsense, as in illegible, incomprehensible, baseless....nonsense. I think I was able to get the general gist of your last sentence, though. To answer, I am 5'10", 175 lb fairly athletic build. My posterior fits just fine in the seat of my 1984 VW Rabbit, which happens to be manual shift. The seats of most small cars are approximately on par with the size of the seats in airplanes. When/If you fly, do you fit in the seat, or do you have to purchase two tickets? Is it the responsibility of the airlines to enlarge the seats and raise costs for everyone else in order to accommodate the increasing percentage of obese people? Or is it the personal responsibility of the obese to take control of their own health and reach a reasonable weight that will allow them to live a 'normal' lifestyle?


I would need two cars, an electric for most of driving which is in nearby cities, and a second for the long drives. I'm not sure about auto insurance. I only purchase liability, but if I have to purchase 2 policies, 1 per car, I would only have the 2nd car. Maybe auto insurance law reform would help the cause of the electric car.

Bob Bastard

Lawrence, I have multiple vehicles. My other vehicles only add a nominal cost on my insurance policy. I suppose the insurance companies are smart enough at least to realize that you can only drive one car at a time, and State registration is only $36/year, so I'm not forced to try to buy one vehicle to suit all my vehicular needs.


I could use an EV with 100 mile range and if I wanted to go further, I would rent a car for the day, put a lot of miles on someone else car. Usually I would need more range on the weekends and car rental companies like to rent their cars at good rates on the weekends.


Um as its a japan only car its built to thier size and your hiney is too fat. Anyway as I said we will only know the true metrics of these ev cars when we have them and can measure it all.

On parking meters that all depends on how they were wired up. Ib some places its likelt to require ripping up the sidewalk to run alot more circuits to handle the load and alot of rather large amounts of power.


@ Alex asked "How much power can a 500cc range extender provide ? "
GreenPlease answered about 20Kw. Depends how you run the engine.

Well, that's a good answer if you are scaling the 1500cc 57Kw 1NZ-FXE engine from the Prius. But that is Utopia, and as Isaiah Berlin said "the abandonment of Utopia is what makes real gritty ground level progress possible."
Now I am sure he wasn't happening to think of the State Of The Art in motorcycle engines at the time but his basic principle certainly applies here. Case in point, if we inspect the 600cc inline four cylinder Honda CBR600RR engine, we find it delivers 88Kw @ 13500 rpm. And it would no doubt deliver reliably for those relatively few and relatively short period of times, say eight seconds to reach 60 mph, needed for vehicle acceleration. Of course this is a great engine to use for input to a stepped transmission on a bike but is rather an elaborate way to supply shaft power to drive an 88Kw electric generator, for arguments sake. The engine has the extreme oversquare ratio of 1.5 (bore and stroke 67mm x 42.5mm) and at 19.12m/sec piston speed comes beneath the 20m/sec reliabilty wall which are both desirable. An interesting thing is that using just two cylinders and adopting an induction motor front transaxle - the performance without a battery pack would not be too bad. If you wanted to pursue this idea to the limit then a single cylinder with the same total piston area but at a less stratospheric piston speed, comes off the shelf as a 450cc with a 62mm stroke and 98mm bore which may do the 44Kw at 9000rpm. Just saying that's all.

Henry Gibson

Any carmaker or other person, who says that batteries are not available for long range electric vehicles, is incorrect and has not taken the effort to find out what batteries are available. ZEBRA batteries could be fitted into a PRIUS with minimal changes to give a full electric range of over 100 miles. The ZEBRA is in production lorries and in the new production TH!NK. The comment about installing a small engine generator with fuel tank represents the best solution to the real but mostly inflated importance of limited range. The TZERO was fitted with a small trailer containing a motorcyle engine generator for long range trips. Auto, HUMMER and SUV makers would not dare tell you how fast a single horse-power could propel their vehicle down a level city street or you would know that their advertised HP is almost mere sales fluff. An average speed would be better than 15 miles per hour which is faster than the normal rush hour traffic flow. Most drivers could not afford to run at even 100 HP for their hour of commute. A ten pound high speed engine of the OPOC design or the RCV design coupled with a ZEBRA battery would give both exhaust free short city commutes and unlimited range freeway travel at 65 mph for the occasional need for long trips. Diesel can be used to reduce the much higher cost of producing gasoline and have a much more stable fuel for long periods of no use. Certain types of biodiesel may have very long lives for storage. Butanol might also work well. Hydrogen and any other fuel for fuel cells and the fuel cells themselves will remain far to expensive for the next 100 years for anything but space research and demonstrations. Coal to Jet fuel (Diesel) conversion plants need to be built and subsidized more than corn-ethanol plants as they are much more energy efficient and do not tend to starve the poor of the world. They would also relieve the poor of the world by reducing the price of kerosine for cooking. Coal to Methanol (and biowaste to Methanol) is much cheaper and produces a fuel with infinite storage life and clean burning in simple stoves as well as engines....hg....

Hi Henry, have to concur with your post.
I would say that this MiEV still not close pricewise when you consider that the Prius battery holds only 1.3Kwh and yet Mitsubishi contemplate a solution using a battery that is twelve times as large. My feeling is that if this vehicle were released for the benefit of early adopters then the accompanying ramp in production could accelerate a complementary reduction in cost similar to the flat panel TV experience. Although shrinking the battery from 20Kwh to 16Kwh shows that technical progress is being made it is still not fast enough by itself to approach the Moore's Law trajectory for DRAM memory i.e. halving the cost almost every eighteen months. On the other hand that ramp up in production, as I suggested, could provide in itself a second driver into cost reductions.
In the meantime the 'virtual battery' idea I've been espousing although not Off_Oil it is Off_a_helluva_lot _of_Oil and would be a good interim solution while manufacturers play catch up on high power full time inverter systems. I also believe there is work to be done deciding whether the architecture should stabilize on a single liquid cooled induction motor driving a differential or on the original twin motor approach used by Impact with air cooled machines.
Anyone know the traction motor power of the MiEV ? A pack that size would be good for 250kW. Of course that could violate the terms of its ZEV rating on account of the smoke from the tires when it lights off !


You might get 88Kw shaft power at 13500 rpm, but once you drive an alternator at 90% efficiency you get less.

I do not know about anyone else, but somehow I can not see a genset screaming away at 13500 rpm under the hood of my car. I would prefer that it were as quiet and long lasting as it could be.


"I do not know about anyone else, but somehow I can not see a genset screaming away at 13500 rpm under the hood of my car. I would prefer that it were as quiet ..."

If it were to be done with automobile acoustic standards in place I doubt you'd hear it.

This is OT here so then if you want to discuss in more detail then post on Edmunds' "Course in advanced hybrids.." on their community forum for hybrids and I'll put up a more technical response regarding alternators and gasoline engines. Repeat your 13500rpm post there and we'll discuss.


Thanks for the invitation, but I like it here. This is a nice mix of less than over wonked types, that have a balanced view of things. Some people think everything is an engineering exercise. The old saying is if all you have is a hammer everything starts to look like a nail.

If all you have is engineering, everything starts to look like an engineering problem. It is much more than that. If countries can not afford the alternatives, they will chose the low cost options. The list of impedances goes on and on and needs to be addressed before we encounter them.

So, a Green Car Congress is just fine by me. We can discuss many aspects of sustainable mobility without any one topic taking over the discussion. I am sure Edmunds has some interesting discussions and I thank you again for the invitation.


Aside from the last few posts by the lurker, this article has been a great read. I applaud Mitsubishi for their accomplishment thus far. Just get this vehicle to the American market asap and price it as listed elsewhere (~$17,000 - $19,000 US) there will be a lot of interest in it.

Count me in the camp of not needing to drive over 30 miles a day. And if I need a longer trip I always rent a car today anyway even though my gasoline powered pollution maker can go as far as I need. Why put all those miles on my car when they could go on someone else's?

For those quick charge fanatics, what is to stop you from having a battery bank in your garage that you charge via solar panels all through the week, use it to quick charge the cars pack when (or more likely, IF) you need to.

Larry Rodgers

According to one post in this discussion,IPCC[whomever or whatever their agenda and/or credentials are] is quoted as stating that one gallon of gas emits 8,788 gms of CO2. My grammar school science[a long long time ago]says in the 1st Law of the Conservation of Matter that matter is neither destroyed or created. 8.788 kg of Co2 is 17.576 lbs of CO2. A gallon of gas is approximately 6lbs. So we are creating about 2 and 1/2 times as much material from the original amount? Or did I get it all wrong in the 5th grade. I am confused so...please help me! For if I remember the law right and my teachers weren't fabricating then I have to believe the science of manipulating the results to prove the theory are in play here.

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