Charging of electric bikes

  • How does charging electric bikes actually work?
  • What is the difference between a ‚charging socket‘ and a ‚charging station‘?
  • What is the technical definition of an ‚e-bike charging station‘?
  • Price comparison of relevant charging station solutions

The huge growth of e-bikes across Europe – over 6 million units sold last year alone – also brings the need for infrastructure not only for riding but also for charging the batteries.

While commuting to work, the rider has a predefined route, which usually does not exceed the capacity of its battery. But in the case of cycling tourism, we expect to have an e-bike at our disposal for the whole day – but the capacity of the built-in battery is usually not enough for that.

According to a recent survey: the majority of e-bike users use them for recreational purposes – 58% of e-bike owners in Germany and more than 92% of owners in the Czech Republic, for example. And other nations are somewhere between that 🙂

The solution is To charge the battery during the day.

Such charging can be done in two ways:

By using your own charger, connected to a 230V „public socket“ or
without a charger via a „charging station„.

How does charging work on an electric bike?

A charger for lithium batteries is automatically supplied with every e-bike.

The majority of e-bikes (<98% in the EU) operate with a built-in Li-Ion battery voltage of 36V. To charge this battery, an adapter is therefore needed to convert the alternating current (AC) from a standard 240V socket into direct current (DC) to charge the battery – typically 42V.

The rate at which the battery is charged depends on the charging current (Amps) and the power draw of the charger (Watts). The faster the charge, the higher the power draw required and also the larger the volume of the rectifiers and therefore the size and weight of the charger itself.

Due to financial savings on the part of e-bike manufacturers, most e-bikes are nowadays equipped with a charger providing a maximum charging current of 2A. Chargers for e-bikes with 2A output have a weight of 0.3 – 0.6 kg. Ideally, it will charge an e-bike by 84 Watt-hours (2A x 42V) in 1 hour – is that enough for travelling? Overnight, such a charger can recharge the battery to full capacity without any problems.

If the owner has an e-bike with a 500 Watt-hour battery (which is basically the lowest capacity offered on the market today), he can charge less than 17% of the battery in 1 hour.

For charging an e-bike „outside the house“, on the road, this small (sometimes also called „travel“) charger is therefore not suitable, because it takes too long to recharge the battery to a meaningful capacity for the next ride.

Bosch Travel 2A (Compact) Charger – for a 50% charge of a 500Wh battery, allow 3.5 hours (recharges 84 Wh / 60 minutes)

It is therefore preferable to have a charger with a higher output current. Any e-bike battery on the market can be charged with up to 4A (at 42V). However, a 4A/42V charger is much larger and typically weighs 0.7 – 1.2 kg. This is therefore a load that most cyclists are not willing to carry with them on a regular basis.

There are also battery types that can be recharged faster (up to 6 or 8A) but here you should always use the battery manufacturer’s charger, the chargers are always over 1kg and cannot be considered a universal option.

Charging with your own charger, connected to a „public socket“

Your own charger and battery must be connected to a 230V socket. The experience of e-bike owners varies: some restaurant and bistro owners are willing to let the owner charge the e-bike, while others consider it an unwanted risk to require it.
For charging, the battery always needs to be removed from the bike, which is not easy for all types of e-bikes with a frame battery.

There are several solutions where an outlet is publicly provided directly for the purpose of charging the e-bike, such as built into the design of the bike rack, or an outdoor wall outlet. Sometimes such solutions are also incorrectly referred to as „charging stations for e-bikes„, which they are not.

The use of a dedicated charger at a public outlet has some pitfalls that the operator should be aware of:

  1. Handling a low-voltage 230V socket can be dangerous for the user if it is not equipped with a properly functioning surge protector. In the event of a user being electrocuted, the operator of the socket may be liable.

  2. The connected charger cannot be protected against the possibility of theft. It is therefore necessary that the owner of the electric bicycle is in the immediate vicinity during the charging period. In the event of theft, some e-bike owners claim damages (the price of the charger ranges from 60 to 200 € depending on the type) from the outlet operator.
  3. Except for special models, electric bike chargers are not designed for outdoor use. In case of rain or even higher humidity, charging from an outdoor socket can easily cause irreparable damage to the charger.

Examples of public 230V sockets – sometimes incorrectly labelled as
„charging stations“:

A better solution – in the case of charging with your own adapter – is the so-called „charging cabinet„: a structure equipped with lockable boxes with a 230V socket where you can place your own charger and battery. The relatively low frequency of use of this type of charging (it is more widespread, e.g. in Germany) is due to the fact that the vast majority of e-bike users do not carry the keys needed to remove the battery from the e-bike and therefore – even when carrying their own charger – cannot use the device.

Examples of battery charging cabinets from Germany and the Czechia:

Certain types of e-bike batteries (in the Czech Republic, this is about 15% of the total number of e-bikes in use) are not compatible with „charging stations“ and therefore their owners depend on the use of public sockets and their own chargers (or carry a „spare“ battery.

Charging without transporting the charger via the „charging station“.

A charging station can be defined as any device that allows the battery of an electric bicycle to be recharged directly via a cable-direct current (DC-DC). Thus, the owner of the e-bike can charge either via his own charging cable or via a charging cable available at the charging station. Unlike the actual charger, the charging cable is typically only 50-70 grams and can be carried coiled in a pocket or bag on the e-bike.

Unlike electric vehicles, electric bike manufacturers are not (and for many years will not be) bound by any single standard for charging batteries, and so there are several dozen types of charging connectors for electric bike batteries on the market. In practice, about 15 types are widely used.

Sometimes the types of charging connectors are misinterpreted by the public as brands of motor manufacturers or as models of e-bike brands, but this is a big mistake. With one exception – the manufacturer of the Bosch E-bike motorization kit, whose batteries are always the same and can currently be charged with two types of charging connectors: Bosch and Bosch Smart, no standard can be spoken of – „Bafang“, „Yamaha“, etc… Information presented in this way indicates a great deal of ignorance on the part of a particular equipment or service provider.

We can find types of charging stations that have charging cables for electric bikes firmly attached to the body of the charging station. The advantage may be the immediate availability of the charging cable, but unfortunately, the disadvantages of this solution prevail:

  • Due to the fixed positioning of the cable, only those types of e-bikes for which the corresponding charging connectors are installed can be charged (usually only 2-4 types), which significantly reduces the number of supported e-bike battery models.
  • Unfortunately, the vandalisation of hanging charging cables – damage or shearing of the cables – is very common.
  • Prolonged exposure of metal parts on the charging cable leads to air oxidation and corrosion. Usually, the charging cable has to be replaced with a new one after one season.

Examples of charging stations with fixed connectors:

Charging stations for electric bikes with interchangeable cables offer significantly more variability. Thanks to interchangeable cables with a charging connector that matches the type of e-bike battery, multiple battery types can be charged and keep the station functional.

It is common for an e-bike owner who uses the charging station network more frequently to purchase a charging cable corresponding to his battery type, or for the e-bike manufacturer to provide it as part of the bicycle package or as an accessory.

Examples of charging stations with socket connectors:

The availability of charging cables is a prerequisite for the use of a charging station. Typically, the charging station operator allows the loan of a charging cable, either physically or through a self-service facility.

An example of the available charging cable sockets for the Bosch system:

Example of the charging cable cabinet:

The technical definitions of „charging station for electric bikes“

In October 2020, the European technical standard for Low-voltage switchgear and control gear assemblies in electric vehicle charging stations (AEVCS) was published as EN IEC 61439, Part 7: Switchgear for use in special conditions.

This standard defines the functions for stations operated by laymen (e.g. by inserting the electrical equipment into the socket and removing it from the socket), for outdoor installations at least IP44 according to IEC 60529 (EN 60529) is required. The degree of protection must also be ensured when power supply lines are connected to the switchgear. Other wiring (e.g. telecommunications, internet) may be installed in the same enclosure provided that no unacceptable interference occurs.

Hence the requirement for compliance with EN 61000-1-2 – Electromagnetic compatibility (EMC): safety of electrical and electronic systems with regard to electromagnetic phenomena.

The publicly accessible charging station for electric bicycles must comply with the requirements of both these and their parent technical standards and confirm their compliance by a report from an accredited testing laboratory.

Price comparison of charging stations for e-bikes

(as of June 2023, source: public company price lists)

econec BIKE BOX mini (econec / ejoin s.r.o.)

Number of implementations: 25
Charging positions max 5 1x 230V
Station body 1691,00 EUR Bosch 4A 242,00 EUR Shimano 2A 176,00 EUR UNI 103,00 EUR 2x, chargers only 2A
Remote control: No

Total price in comparable configuration: 2.557 EUR 6P ( s.r.o.)

420 implementations
Charging positions max 6 2x 230V
3x UNI, 2x BOSCH, 1x Shimano – all chargers 4A 2x 230V
Remote control: yes via Cloud APP, free of charge

Total price in comparable configuration: 1.979 EUR

BikeEnergy (MEGAtimer GmbH)

Number of implementations: 1460
Charging positions max 4, all chargers 4A
Universal charging also for e-bike systems with communication
Remote control: yes, price unknown

Total price in comparable configuration: 6,368 EUR

Price comparison per charging port:

Bike Energy – Point 4: 1 596 per charging port, incl. communication
econec – eBIKE BOX mini: 450 € per charging position, excl. communication – 6P: 261 € for one charging position, incl. communication