Battery Temperature

Deutsche Version
From the MINI E-team I got an e-mail that says: When the battery temperature drops to 5°C (41°F) or below, the MINI may not start.

Driving the car for a longer distance means rising the battery temperature to higher values. Driving the car regularely avoids dropping the temperature to critical values due to the slow cooling-down of the battery pack.

My daily commute is only about 20km (12.5 mi) in total. That means for the single trip with a distance of 10 km (6,2 mi)  a gain in battery temperature of  2-3 °C (5-7°F).
At ambient temperatures of -7°C (19°F) i  had typical battery temperatures of  2°C (35,5°F) with the car parked in the unheated garage. Driving to work results in a battery temperature of about 5°C (41°F) before leaving the car for the next 8-9 hours in the parking structure which causes again a drop in battery temperature to 2°C (35,5°F).  Now i'm avoiding the open park decks over the ground and hiding the MINI E in the basement expecting more pleasant ambient temperatures.

So with this situation I really have a little problem now, because I can not ensure higher battery temperatures and this may go worse when the ambient temperatures fall.

At battery temperatures of 1°C (34°F) and below the MINI refuses to charge. In this case you have to drive the car until the battery temperature rises or you have to install an additional heater powered by a separate wall socket.

Battery to cold for regenerative braking. This indicates also, that charging may not be possible.

Yesterday  I had a battery temperature of -2°C (28,5°F) with an SOC of 20%. I was driving a short distance just to ensure that the car is still operational except regen was completely disengaged.
I parked in front of the garage but still outside and let the car activated with the cabin heater at full power and the fan at second setting. This method has two effects: Activating the battery with the high power consumption of the cabin heater. And venting the battery with warm air from the cabin.
After one hour I returned and the battery temperature was 8°C (46°F) and SOC about 15%.
Because running the heater affords activation of the high voltage system I had to let the key in the car. I locked the car with the emergency key, so this could be done at a public place if necessary.

Using emergency key to lock door when car is activated.

 The question is: If the battery temperature drops below the point were the car refuses to drive, will the high voltage system be operational to execute this method of rising the battery temperature?

After that I charged the MINI at the wallbox with the 32amp-setting, but still outside the garage.

The next morning the car was still charging. Although the car had spent about 11 hours connected to the wallbox,  SOC was only at 75% and battery temperature dropped to 3°C (37,5°F). This was not the first time I noticed a significant reduction of the charging rate when the battery temperature is low.

The self generated heat when charging at 32 amp is not sufficient to rise battery temperatures to an optimum level at low ambient temperatures. So a fully charged battery at 3°C (37,5°F) cannot store the same amount of energy as it could at 20°C (68°F). This leads to the often discussed range limitations at cold weather. In addition to this the extensive use of the cabin heater intensifies the effect.

Keeping the battery at convenient temperatures with an additional heater like Jim McL did is the best solution for the MINI E to face low temperatures when full range is needed.

Compared to the beginning of the test now I connect the car to the wallbox every day to keep the SOC as high as possible to have more energy left in case of "off grid self heating" is necessary.

14of612, MINI E-collective, regenerating in it's alcove.

Guest entry on Tom Moloughneys blog

 Deutsche Version
Tom Moloughney, driver of #250, asked me to write a guest entry for his own blog.
Tom is the most active and most famous MINI E blogger and with almost more than 45.000 mi driven he has the highest mileage of the whole test-fleet.

I fulfilled Toms request  and gave a brief summary of the MINI E program in Germany.
The following will link to the page of my guest entry at Tom Moloughneys blog:

http://minie250.blogspot.com/2010/12/mini-e-driver-stefan-reitmeier-checks.html

MINI E in the snow

Deutsche Version

At the weekend I visited my parents again. After a 71km trip the charge level was reduced from 96% to about 25%, but I was pretty fast on the highway. During my stay I was able to recharge the MINI for about 6 hours at 12A/230V, which was sufficient to get the SoC to 86%.

Charging at 12A/230V in the heated garage

On the way back I visited an aunt. I was very relieved that I had chance to plug in MINI E for another two or three hours. So a achieved a full charged battery before driving home on the highway. Due to adverse weather conditions i drove moderately and reached home after 70km with little more than 20% SoC and 30km left.

I've parked the MINI at the return in the open, because on Monday I was not working and the garage was already occupied by the second car of the household.

MINI E 014 in the snow

The next morning the car was completely snowed. The outside temperature was -7°C, were the battery temperature was still at 16°C. After the trip the temperature was at about 35°C.

The following re-charging costs me 20kWh electricity of 20.7 Eurocents/kWh. Extrapolated to 100 km this are about 5.80 €. At the current diesel price of 1.30 €/l this corresponds to a diesel consumption of 4.5 l/100km for financial tie.

Two month with MINI E

 Deutsche Version

I'm driving MINI E # 014 for two months now. So far no breakdowns occured and I'm still completely fascinated by the electric driving .

Although I use the car almost every day, the trips are short. The current mileage is 13067 km, i.e. since receipt of the vehicle I drove 1591 km. This means about 800 km per month, which is pretty much for my circumstances.

90% of the trips take place exclusively in the city, the other 10% is pure highway driving at higher speeds.

Engine sound:
Inside the vehicle, the engine sound is noticable (with shut off radio) and you have some response caused by the driving conditions (such as the typical buzz that appears in recuperation mode from higher to lower frequency dependent on the driving speed).
Since the sound is not too loud nor unpleasant in the frequency spectrum, I think an appropriate and "natural" electric motor sound in the interior would be useful. The same is true already for normal combustion engines that are on the one hand provided with a sophisticated sound insulation, on the other hand it should be quite noticable for the driver in certain situations (e.g. intense speed acceleration).
An artificial distortion of the electric motor sound or even the acoustic simulation of a combustion engine, I do not consider expedient.

The low operating noise of the car is very pleasant, but it requires a correspondingly prudent driving. Until now there was a single situation where an elderly lady was crossing the street and did not notice me, because she was intensly watching the street to the opposite direction. Accordingly, she was surprised when she finally realized that I had already stopped on the other side and waited until she finished crossing the road. But perhaps she wouldn't had noticed me even with an conventional car.
With the low temperatures much less pedestrians and cyclists inhabit Munichs streets than in the summer, so I currently see no problem with the low external noise.

Recuperation:
I like the strong retarding when releasing the accelerator pedal very much, because with metered changes of the accelerator pedal position you can control the speed very accurately.
Personally I prefer the strong braking effect on the recuperation more than a little braking effect or even a "sailing operation," in which the vehicle does not brake at all and acts comparable with a conventional car with the clutch pedal pressed and rollin on unabated.
Choices between different modes for the recuperation, such as those in the A1 e-tron via shift paddles on the steering wheel or on a pre-selection of the gear lever as in the Mitsubishi iMiEV may be helpful at the beginning  for inexperienced e-car drivers. But then maybe a consistent implementation and adoption of e-motor-specific advantages of speed control only via the accelerator pedal is avoided.
However, with the different opinions on this topic, an appropriate choice or a "personal" adjustment of the braking performance should be provided.

Since even the MINI E typical strong retarding effect is sometimes not enough, I think a feature of the AVL eMini is an useful addition. The description for this car says, that with a light touch of the brake pedal you increase the regenerative braking (which should already be active when the foot leaves the gas-pedal). The mechanical brakes are activated at the normal pressure on the pedal. This does not help for the "one-pedal-strategy", but provides more regenerative energy.

Charging:
Until now, I'm charging the MINI E  as rare as possible. As my rides are predictable and a second car available, its not necessary to have the car always in a 100%-SoC-condition.
With SoCs of 40% or residual ranges of 50km I have not a big problem on short trips. This was different at the beginning of the test. However, with the temperatures falling I have to call my just won trust in the estimated range into question.

Charging is very simple, but the handling of the inflexible and stiff charging cable is uncomfortable.
A more flexible, perhaps self-retracting cable or even wireless charging based on induction would be an enormous advantage for the daily use of an electric car.

Annotation: here in Germany the cable is not a permanent part of the wallbox. We have a single cable to connect the Mini to all types of charging stations. If you want to carry the cable with the car to use public stations or to have it available just in case of need, you'll have to do all the uncoiling, connecting and restoring operations any time you use even the home wallbox.

Munich and MINI E #014

Charging at a public charging station

Deutsche Version

Charging the MINI E at a public charging station from Siemens is easy to handle. The following photos describe the procedure.

public charging station from Siemens operated by Stadtwerke München

description of the procedure

identification via RFID-chip

cover can be opened after identification
1 x IEC Typ 2 (400V, 32A)
1 x Schuko (230V, 13A)

plug in the cable to the car

           

plug in the cable to the charger

closing the cover starts the charging

MINI E charging at the Knorr-street

Visit of the eCarTec 2010

 Deutsche Version

On Wednesday i visited the eCarTec 2010 Expo at the exhibition center in Munich Riem (http://www.ecartec.de/ ) by an invitation of the MINI E-Team.


 Stand of BMW
At the stand of BMW there was MINI E # 046 and the Active E (the known concept vehicle, not one of the new vehicles for the future field test). As a traditional vehicle, an electrified BMW 1602 was shown.The car was used as a support vehicle during the Olympic Games 1972.

8 of the 12  batteries in the former engine room of the 1602. The other 4 are located below.

From the future MCV the drive train could be seen.

Batteries and drivetrain of the future MCV.

Other
Furthermore at the show a variety of chargers, plugs, etc. .. were shown, which i looked at not in detail i have to admire. The electrical power suppliers e.on and RWE in any case already stirred vigorous promotion for their new market ...

 ... and at Lotus they tried to give the electric drive the sound of a powerful gasoline engine. Not only unnecessary, but rather silly.


Another variant of a MINI with electric drive

I was most interested, however, in the eMini of the company AVL. It is a concept car with a serial hybrid drive.

In the serial hybrid drive, the vehicle drives solely with the electric motor. The on-board internal combustion engine drives a generator which recharges the battery or directly powers the electric motor. It is not mechanically connected to the drive train. This so-called range extender (REx) can be positioned anywhere in the vehicle.

In contrast to this in a parallel hybrid the combustion engine drives the drive axles via a conventional transmission. An electric motor supports the combustion engine and is able to move the car at low speeds. The battery is charged either by a separate generator driven by the combustion engine or by the electric motor driven through the gearbox from the combustion engine to run as a generator. Furthermore, the generator / electric motor can create power via regeneration by deceleration. Is the vehicle a "plug in", the battery can be charged additionally by the wall socket.


 But back to AVL eMini, which Rex is also called "Pure Range Extender" due to the lack of mechanical connection to the drive train.

Interestingly, the Audi A1 e-tron uses exactly the same concept with identical specification.

Package of the AVL eMini

The vehicle has a battery capacity of 12kWh (MINI E: 35kWh). Pure electric range of about 50 km should be possible. The electric engine has 75kW for short periods. This is exactly half of what the MINI E has available.
If necessary, a Wankel internal combustion engine charges the battery by a generator with an output of 15 kW. Due to this another 200km should be possible. Through the skillful arrangement of the components in the AVL eMini the back seat survived. Even the trunk has almost original size, except for a slightly raised ground.

AVL eMini

Battery in typical T-arrangement. It uses the space of the exhaust system and the fuel tank.

The compact AVL Range Extender Module with its wankel engine below the trunk.

This concept sounds very well, but there are some drawbacks.

The specified range of 50km electric + 200km by range extender can not be driven at once. Since the Range Extender provides much less energy for the battery than the engine cosumpts on higher speeds, after 50 + x km a break is needed. x depends from what point of the range extender will start loading and in which time the 50km are driven.
According to my conversation partner at the stand it takes the range extender about 2 hours to get a completely discharged battery to a SoC of 100%.

If the battery was completely empty, the output of the generator is only enough for a modest speed of 45 km/h. This is just acceptable in the city for urban driving, but not for highway driving.
A real range of 250km, which can be increased by simply gas refueling for another 200 km, can not be realized by the car.

For this a much more powerful range extender would be necessary which also may have a direct drive in the drive train for high speeds. This is a feature of the Volt/Ampera or the "Boosted Range Extender" by GETRAG. This solution blurs the boundaries between the parallel and serial hybrid. Since this detail of the mechanical connection of the combustion engine to the drive train in the Opel Ampera or Chevrolet Volt was revealed recently, there was discussion whether the Volt /Ampera is a pure electric vehicle or just an ordinary hybrid à la Toyota Prius. The fact is, that the Volt / Ampera can not drive solely with the internal combustion engine. (Link 1, Link 2)

... um ... back to Emini.
For me as a user  the AVL eMini has no discernible benefits compared to the MINI E .

    * For the short daily commute of a total of 20km a range extender is not necessary.
    * The low battery capacity requires more frequent and more consistent charging on the socket to avoid the use of the Range Extender with its expensive fuel.
    * A ride beyond the electrical range also requires careful planning,  because the range increase by the Rex depends on several factors. Even if the Rex is allowed to run unattended during a planned break, this shall be possible under the open sky, but not in a garage or parking structure.
    * A trip of 70 km highway is no problem for the  MINI E. I'm not sure, whether the eMini manages this distance even with the REx started immediately.


However, the eMini has no limitations on space. In principle this is a possible "series" solution, whereas the MINI E was never intended as a series solution. And so the respectable battery capacity could be realized by rigorous elimination of the rear seat and a part of the trunk.
The REx module gives the eMini with the restrictions of the limited space available more flexibility than an for example 5kWh higher battery capacity, which could have been installed instead of the REx.


 Other reasons in favor of the concept are:

    * Space, cost and weight advantage by reducing battery size
    * More "endurance" in traffic and traffic jam, when many electrical accessories are turned on
    * Support of vehicle climate conditioning (for this vehicle not yet implemented)
    * ...

 Anyway, I'm excited about the experience made with the A1 e-tron. Therefore a small test fleet of 20 vehicles will be on Munich's roads in 2011.

Hand over event

Deutsche Version

So finally today the hand over of the cars was celebrated in a ceremony at Munichs Odeonsplatz and the Residenz. It was  a mind-blowing feeling to know that one of the cars parked at the place will be soon my primary means of transportation.

MINI Es at the Odeonsplatz

Between bites, cappuccino and talks to other prospective MINI E users I got the key and the contract documents. The car with the number 014 should be my future set of wheels.

Where is  #014?

Found!

Equipped with the key I could get a first impression of "my" MINI. The car was not a new car. It was one of those that already had a one year lease period in the USA. It was overhauled before beeing part of the new project.

The mileage was 11476 km (7132 mi).

Mileage.

Soon after the program started on the specially built stage at the Odeon Square with speakers from politics and from the project partners.
Unfortunately the weather was pretty cloudy, wet and windy, so it was difficult for the relatively few guests both holding the umbrella (which was by courtesy of the project) AND donating appropriate applause.

an example for both politics and project partners: Munichs mayor  Ude und BMWs member of the management board  Dräger

From the 40 MINI E the Bavarian Red Cross received 10 cars, 26 cars went to private users and 4 remained at the project partners.

On the stage there was a key hand over ceremony to a representative of the Red Cross as a carfleet user and to a representative of the private MINI E users (a photogenic lady with a daily commute of 54 km (33,5 mi) for the single distance).
In the end every speaker took part in a photo shooting demonstrating the "refueling" of a BMW MINI E at a charging station of SIEMENS, powerd by the SWM in MUNICH and subsidized by the FEDERAL GOVERNMENT.

Potoshooting

An official version can be seen at:
http://www.siemens.com/press/de/events/corporate/2010-09-emobility.php

What a coincident, at the street beside the event two cars were parked which represent also for the uncompromising e-mobility without restrictions (except range).

Tesla shows presence.

The first trip from Odeons square to my home was without any problems and was pretty fun.
Nevertheless #014s first practical test was imminent. 75km (46mi) to the home of my parents, predominately German autobahn.

SOC was at 80%, so I plugged the car to the new wallbox in the garage. It took 10kWh to achieve SOC of 100%. Estimated range was at 130km (80mi) which seemed to be sufficient to dare the journey.

First I was driving very cautious and keeping an eye on the SOC, which was rapidely moving. But the estimated range always had a safe surplus to the distance to destination.
So my driving became more briskly and I remembered one of the numerous "rate-the-following-statement"-style questions that was: I have convidence in the display of the estimated range. I answered by putting a check mark to: I largely agree.
So I should do so...
In short, despite a travelling speed between 120-140km/h (74-87 mph) and some 152 km/h (95mph) -peaks I arrived with a estimated range of 48km (30mi). So #014 passed its first test.