City-el / Mini el tips + tricks

These pages are under construction, some T+T have been moved to the Repair Procedures page.

Translator's note: I haven't translated all of Ralf's original page, and I haven't kept the order intact -RRY


These pages are experiences to pass on in the hope of helping other. Originally I wanted to write a " do-it-yourself " book for " el ", that was 1992. Meanwhile media like Internet arose, over which one the information can pass naturally for you mini el / City-el pilots for free.

Some the errors and peculiarities described here do not occur with newer vehicles.

All specification are without guarantee. If someone incorrect information discovers send please an email.


The mini el, mini el city is called now " City-el ", since the name " mini " is protected, by the Rover Group Inc. (Mini Cooper). For the sake of simplicity it is mentioned in the following text " el ".


El has already a quite interesting life behind itself. I am told that a Danish mechanical engineer saw a Science Fiction film that showed small vehicles, whereupon he got the idea to make ones just like it. First series with around 50 vehicles were built. With different financial sources around 1989 the mini-el Series 1 were developed and produced. Series 1 vehicles were actually meant only for Denmark. Tips and Tricks for series of 1 vehicles many more pages like these would fill, since these vehicles were more trouble-prone than today's els. Mine is from this series... Their susceptibility to electrical interference was the end of the first company, which could not handle the cases of warranty any longer. The vehicles were then sold at bankrupt's auction.

Series 1

Outwardly they differ from current vehicles only by a cover over their two headlights. The instrument panel had two LCD bar line displays instead of the todays round LED instruments. The operation of some functions was controlled via switches on the right by the steering wheel. For the motor control a hydraulically regulated pre-resistor was used.

The motor was a permanent-excited direct current motor, by the way with clearly lower electrical consumption than the new Compound motor. With standard batteries and 36 V it gave 70 km range. Unfortunately the vehicle with 1kW rated output was at least under-sized for hilly conditions. Many of the old vehicles are re-equipped today with pulse width modulating controllers and with the new motor and do faithfully service; my own vehicle has over 50.000 km.

Series starting from No. 2000

Starting from summer 1990 there was a new mini el, starting from serial number 2000, it was improved in every respect, with a better motor, electronic motor control, 12V electrical system, altogether interference-proof electronics in Surface Mount technique.

Series starting from No. 3006

May 1991 was continued to change the new mini el still, starting from serial number 3006 - different sections in the electrical connection were modified, were not improved necessarily all. The four individual contactors for engine control were exchanged for double contactor, for which unfortunately very much annoyance makes.

In June 1991 the company sold out and the successor company was called now City- Com. Since March 1992 it produced the colored mini els with the painted roof. Starting from serial number 3650, additionally gives it a rubber protective sleeve for the steering column, and a better seat.

Since Autumn 1992 the mini el city is called the City-el and a new principal shareholder from Germany with City Com had entered.

Since 1994 City- COM is owned by Karl Nestmaier in Germany.


City-el's at the moment are sold in Denmark, Switzerland, Germany, Austria, Holland, Great Britain, Sweden and USA. In Austria by the way with moped permission starting from 16 years. Even in Australia!

Traffic light

As an el driver get used to being stared at - smile always -


The left rear wheel sits rigidly on the rear axle, rights by a friction clutch (slip clutch) is propelled. This clutch can produce noises. To reduce these noises one can grease the clutch disk at the wheel, however it loses its affect. (I use limited slip differential additive, which seems to have the desired properties - RRY)


We do not want City-el defined as an auto. Max Horlacher, a well-known electric vehicle pioneer, said once, " auto is large, heavy and stinks ". We define el rather than electricalmobile, or electric vehicle. " Large one " autos (Úr BMW, Mercedes 190 with an electric motor to equip is not meaningful, since thereby no primary energy is saved; one can call it only "Electro Tank". Over 80 % of all travels in Germany are under 50 km and the vehicle is filled only with one person, therefore the emphasis should be set on small, light vehicles. The large vehicles can drive also only, if the high-energy batteries or appropriate gas cells are series produced, with today's lead-acid batteries their range is only 50km or. An experimental MB190 with nickel cadmium batteries also only 60km range has. There we are not situated at all badly, since with NiCad batteries a City-el has 70-100km range.


Electronics el are manufactured using Surface Mount Devices technique and therefore are quite insensitive to vibration and interference.

Electrical gas station (charging stations)

In many cities there are electrical gas stations, in the link list there are databases for Europe and the USA.

Driving current

The driving current on the level amounts to about 35 ampere, at 40 km/h. In the mountains the driving current is limited by the battery power to approximately 130 ampere.


El has conventional lead acid batteries. They have a rated voltage of 12V and a nominal capacity of 90 ampere-hours with five-hour unloading. The three batteries are connected in series and have thereby a total voltage of 36 V. This corresponds to energy content of 3 kilowatt-hours. Also batteries of the manufacturer DETA / LEVO / Hawker with a capacity of 100 ah C5 are available with 30% more range and I find thereby fewer stress offer.

Battery capacity

The standard City-El Yuasa batteries have a nominal capacity of 90 ah C5, this is unfortunately named, as you can not discharge 90 ampere for one hour. This capacity is counted over 5 hours of unloading, i.e. 5 hours of unloading at 18 ampere. Since however almost always with higher discharge current one drives, the amp-hour capacity is reduced to approximately 50 ampere-hours at one hour of unloading. That is, the higher the discharge currents are, the smaller become the amp-hour capacity of the battery.

Battery life

The life span of the batteries depends very strongly on the driving and loading history. Normally one counts % remainder capacity in the case of lead traction batteries on one life span of 400 - 600 load cycles, i.e. 600 unloadings up to 20%. In kilometers the life span is situated between 3.000 and 12.000 km. Over-dischargings, unloading with high currents and overloading strongly shorten the life span. At low temperatures the battery can freeze if it is discharged fully, with bad consequences. An el-pilot charges at each plug socket, even if there is only 10 minutes " intermediate loading ". Never store a City-el discharged.

GFI protective switch (in Europe RCD or FI called)

A Ground Fault Interruptor protective switch belongs in each electric circuit at which a vehicle is charged. It monitors the line current and the current reversal of the vehicle. If due to an error in the vehicle or its cord a non-operate current, e.g. by a damaged cable, flows, it switches off independently. One should take thereby a FI protective switch with 30 mA nominal trigger current, he can lives save. Errors, e.g. that mains voltage is at the vehicle chassis, can occur e.g. by short circuit through with mains-fed battery heaters. Battery heating is not standard in el, but as accessories available. GFI switches are also built into extension cords plugs.


El is relatively quiet; therefore one should direct a special attention toward pedestrians and cyclists. I had contact in my el with a pedestrian, without injury to either party.


The hood el consists of acrylic glass with let in laminated glass windshield and side windows of safety glass. The hood is strengthened with a glued on, in-foamed steel tube. There were again and again problems with hoods cracking, whether closed or Cabrio.

Cable Routing

In el there are two "cable tunnels". One leads from on the right in front up to the front brake, the other one from the emergency brake into the engine compartment. In both cable tunnels there is enough room for the transfer of loudspeaker lines or the like.


Charge thy el as often as possible. An electric vehicle revives at each plug socket again. With one hour to charge one can good-make almost 10 km, thus daily mileage of more than 200 km is possible.

Battery charger

The stock el battery charger charges the battery using a special characteristic to preserve the batteries. 80% battery capacity is achieved after approximately 4 hours. The battery charger is divided into the transformer in the back and load electronics under the seat. The battery charger considers variations in temperature and regulates the load characteristic accordingly.


In an internal combustion vehicle the topic heating is not a problem, since sufficiently waste heat from engines is available. With an auto easily 100 kW of waste heat from engines meet, this for the heating of a gymnasium would be sufficient. With el heat come from the battery and is with 800W quite insufficient and nevertheless current-eating. For keeping free the windshield mostly, the small heating level or opening the external circulating air flap is however usually sufficient. The vent in the spoiler leaks a lot of cold air in the winter. One can lock this opening with tape.

Magnetic fields

Electric motors function with magnetic fields; unfortunately also emit stray fields in the vicinity of the motor. The motor el is situated just underneath the black motor cover; one should therefore no diskettes, audio or videocassettes on the engine cover put. This is an unofficial warning, since I noticed discolorations of the television picture after the running a television in el, which disappeared however after two hours. I could execute unfortunately no measurements of the scattering fields and do not know it's strength, or how dangerous these fields are. The field in the proximity of the radio or in the jacket pockets of the driver is however in any case uncritical.


In el a direct current Compound motor of the Danish manufacturer Thrige Titan does service. Its rated output amounts to 2.5 kW. When starting it delivers up to 4 kW. The life span of the carbon brush conductors is approximately 50,000 km. The life span of an electric motor is much greater than a combustion engine. With my vehicle hardly and brush wear abrasion was to be seen after 30.000 km of driving.

Ruined armature shafts

Some other drivers and I broke the motor shaft off. In early vehicles, a drilling at the motor shaft had been too deeply bored, so that there were some problems with motor shafts. This damage is however reparable without exchange of the motor.

Motor control.

With el a pulse width controller of the company Curtis regulates the direct current motor. A transistor can switch on or off the current only. In order to get an infinitely variable rate control nevertheless, one times the current pulses. Short on times and long time-outs for slow driving and vice versa. The frequency of the impulses is with 15 kHz. The rated voltage of the output transistors on this controller is 24-36 V; therefore it cannot be used with 48 V driving rated voltage.

Mains voltage check

El unfortunately has none. Tip: it inserts a fluorescent lamp into the transformer housing then one has the check immediately after putting in whether mains voltage is there.


El can be cleaned very well with neutral soap and warm water. Small scratches and dirt remainder can be removed with lacquer cleaner or polish.

Wheel nuts.

The wheel nuts are self-locking. You do not have to throw them away after each use, but a certain resistance must be there! (I almost lost a wheel due to a nut loosening up - RRY)


From rust the plastic auto is to a large extent spared. The only metal part that annoyance can make here is the battery basket, one should check occasionally for rust. If the plastic coating chips off, one should treat the places.

Side window

There is a sliding side window available, unfortunately it's not cheap.

Solar Mobile

One calls solar mobile electrical mobile, who's driving power solar was produced. Only part of the driving power required could be produced using vehicle-installed solar cells. Better is a stationary solar plant with electricity fed into the mains.

Peak Shaving

Peak load times of the power stations are mostly in the morning between 9 and 12 o'clock, don't charge during this time if possible.


While charging or in the morning briefly before driving off one can heat the vehicle with an electrical heater, however great caution is required. Fire risk! Also one should not directly illuminate the plastic of the body, it is press-molded and tries when heating up to return to its original form. A trick is to place the heater on the mat next to the pedals and be let toward backrest blow. The inserted large heating level uses more energy than the battery charger gives! Also a hair dryer, small and easily, can carry good services out.


A can of "flat-fix" or the likes as back-up for the missing spare wheel can be very useful. "Rain-X" or the like is essential during the cold season to keep the inside of the windows clear. A tarp or ground cloth is useful if one should crawl under the vehicle during repairs, or if one wants to render help at an accident. If one puts this cover folded up on the engine cover, the motor noise becomes still quieter. One who is technically knowledgeable can also carry a digital multi-meter, they are very cheap these days.

Optional battery charger

Zivan K2I have been very happy with ZIVAN battery chargers as additional chargers for el. The battery chargers have rated currents between 20 and 40 A for 36 or 48 V depending upon type! With a full charge in 1 to 2 hours, one can obtain fantastic day ranges. I drove already several times from Stuttgart to the Bodensee - into 6 hours! This is a two-hour drive in a normal auto. (These chargers have electronic taper charging, and, if properly adjusted, can be left unattended, unlike the next idea -RRY)

Cheap Fast Battery Charger

Who has little cash... can buy for approx. 100, DM a welding set in the building market buy and in add an electric rectifier with at least 40A rated current. The output of the welder is lead to the alternating voltage inputs of the rectifier. The welding cables can serve as leads for City-el. The electric rectifier onto a large cooling radiator in the welding set install. The battery charger should to a plug connector in a secure place to battery power set attach. This charger can supply 36V at approx. 40 A and 48V approx. to 28─ with construction costing approx. 150, DM. Caution, this battery charger has no regulation electronics, i.e. there is the danger that the battery is overcharged. Usually one uses it however as quick-charger for only a half-hour.

letzte ─nderung 13.09.99