What types of electric car chargers exist?
We can divide electric car chargers according to their application, i.e. Charging stations(commercial chargers) and chargers for private use. Charging stations can take on different appearances and have different outlets, power, etc.
Commercial or public stations - depending on the location of the charger, either CCS fast chargers are installed - mainly along highways, expressways, etc., or AC chargers that can only charge up to 22 KWH (charging speed depends also on your car capabilities, usually 11 KWH with AC and 250 KWH DC). AC chargers can be with a built-in cable or just an outlet. Such chargers will usually be found at city parking lots, shopping malls/stores and hotels/restaurants. Public chargers in Europe will always be equipped with Type 2 / CCS connectors, sometimes there are additional connectors available, such as CHAdeMO, but this is not the rule. The availability of connectors can be checked in the application of the charger or in mobile applications such as plugshare.
AC stations (3.7-22 KWH) that require their own charging cable
AC stations (3.5-22 KWH) with an aggregated cable
DC stations (50-350KWH) with integrated charging cable. Each fast charging station always has an integrated charging cable.
Private charging - depending on the needs, each electric car driver decides whether he or she will also charge on a daily basis at home or in the company, and must choose one of three types of chargers. For personal use, fast DC charging stations can also be purchased, but their cost and legal or connection power requirements strongly discourage such investments.
Portable charger for home outlet (3.7KWH)
Portable charger for power/camping type connector(3.7- 22KWH)
Wallbox type charger (3.7- 22KWH)
How fast will it charge an electric car? Internal car charger, kilowatt hours, amps, AC and DC.
- Charging Power (kW): This is the primary factor that determines how quickly a battery will be charged. Charging power is expressed in kilowatts (kW) and depends on the charging station and the car.
- Battery Capacity (kWh): Larger batteries require more time to fully charge. Battery capacity is expressed in kilowatt-hours (kWh).
- Battery Charge Status: Batteries charge more slowly as they approach full charge. The last 20% of charge may take much longer than the first 20%.
- Battery and Ambient Temperature: batteries charge more slowly at low temperatures. Some cars offer the functionality of warming (preparing) the battery for charging before arriving at a fast charging station.
- Battery Technology: Different battery technologies have different charging characteristics.
- Connectors and Charging Cables: The type and condition of the connector and charging cable can also affect the charging rate.
Every electric car runs on direct current (DC), where we have alternating current (AC) in the electrical system - hence electric cars have a built-in inverter that converts alternating current into direct current. Hence, depending on the type of charger (AC/DC), we can charge the car's battery directly (in the case of DC chargers with a built-in inverter) or we must use the inverter built into the car when charging with AC chargers.
Three key parameters of the car relevant to understanding the charging speed:
- The power of the built-in inverter and the number of phases supported, e.g. 1 phase 16A/32A, 3 phases 16A/32A, which translates into the following power output
230V x 16A x 1 phase = 3680W
230V x 32A x 3 phases = 22,080 W - Maximum supported charging rate by the battery (e.g., 240 KWH)
- Capacity of the battery (e.g. 60KWH)
Example
Tesla 3, battery capacity (78 KWH), maximum AC charging power (11KWH), maximum DC charging power (250KWH).
With a 22KWH wallbox we are still limited with 11KWH charging speed of the car.
Estimated charging times for a full battery (from 0%)
Portable charger 3.7 KWH: ~18 km/h; 0-100% 21 hours
Wallbox charger 11 KWH: 55 km/h; 0-100% 7 hours
DC 100KWH fast charger: approx. ~500 km/h, 0-100% 45 minutes.
The state of charge of the battery affects charging speed. See the diagram below for how charging slows on a fast DC charger during typical charging.
source: https://insideevs.com/news/519382/tesla-model3-82kwh-charging-analysis/
Is it possible to charge an electric car at home faster than 22 KWH (about 100 km/h)?
In theory, we can purchase a commercial DC charger with a CCS connector that supports, for example, 100KWH, however, in addition to the high cost of the equipment itself (e.g. 100K), there are two key issues:
- Connection power - a typical single-family home has a connection of 12KWH. Often it is not physically possible/available to make such a power connection with parameters matching requirements of a DC charger. In addition, the cost of maintaining such a connection can be houndreds of euros. Connections above 50KWH are also served by commercial tariffs with much less cost-effective rates for individuals.
- An electrical installation above 50KWH requires designs, building permits, acceptance, approvals from the Office of Technical Inspection, etc. Usually process takes months and doubles the cost of the charger itself.
A charger with what power to purchase?
It all depends on your driving profile, the most optimal is to have 3 chargers:
- Portable socket charger 3.7 KWH
- A charger with the ability to connect to the red power socket (ideally with additional adapters/adapters for a blue camping plug or small power socket), such as 7-22KWH
- Wallbox 22KWH
A 3.7KWH portable socket charger with amperage reduction will help us charge in basically any conditions. Any such charger is single-phase - and the limited number of wires, by not having 2 and 3 phases in the cable, makes the product cheap. This is by far the slowest way to charge, but will allow you to calmly recharge about 37 KWH overnight, or ~200 kilometers. By default, all portable socket chargers have the same parameters, that is, they support 16A (16A * 230 V = 3,680 W -> 3.7KWH). All we need here is a working outlet that can handle 16A and a properly working electrical system. Our experience shows that up to 30% of electric car users plug chargers into outlets with a non-functioning grounding, inverted phase with a neutral wire. Most chargers from reputable manufacturers will not work properly in the absence of grounding. Every electric and plug-in car supports charging at least 3.7 KWH.
Portable red-plug (CEE) power charger - these are chargers that can support from 1 to 3 phases, from 16 to 32A, that is, in this group you will find 7, 11 and 22 KWH chargers. They are most often sold with a high-power CEE 5-pin plug (32A), but there are also chargers on the market with smaller 5-pin plug (16A) and a camping plug (CEE 3-pin). A part of such chargers have functionalities known from wallboxes like mobile applications, RFID card support, wall mounts, etc.
Wallbox type chargers, which are chargers permanently mounted on the wall. They are the most extensive in functionality, examples of charger functionality: mobile application, RFID card support, Bluetooth/WIFI, display, integration with PV installation or DLB (Dynamic Load Balancing). Wallbox-type chargers are available in different wattages, and we recommend buying one with a power reserve even if your current car does not support, for example, 22 KWH. Wallbox type chargers are built to last. We recommend buying a 22KWH unit that will be able to support future cars. Despite the higher power of the charger, we can use such a charger with a less powerful car - the car will only use the amperage it supports. Please remember that if you have a car that supports 1 phase with 32 A (7,4KWH) you need a 7,4 KWH or 22 KWH charger to charge at full speed.
Additionally, due to the larger size of the charger itself, such chargers are often equipped with a much larger number of protections, such as Type B RCDs.
I bought an 11KWH charger and the car is charging only 3.5KWH!!! - The trap of cars supporting only 1 phase with a maximum charging speed of 7,4 KWH.
The 11KWH charger is nothing more than 3 phases of 16A each. If your car supports only one phase then it cannot use the other two phases. The car having 1 phase available will charge according to its limitation and the limitation of the charger. The most common situation we have to deal with is:
Auto supporting 32A and 1 phase (7.4 KWH) and 3-phase charger 16A (11KWH). In this case, we will use only 1 phase with 16A, so 230V x 16A = 3.7KWH
Is my house electric installation ready for an electric car?
Below you will find some considerations to take into account when evaluating your electrical installation. Remember that the installation should be designed, executed and verified by a qualified electrician, who will first review the data sheet of the charger you purchased. Aspects of the electrical installation that should be verified:
- connection power and number of phases served - we may have a contract with an energy supplier for only, for example, 7 KWH with one phase. This will prevent us from using additional phases in 3-phase chargers
- Properly working grounding - in older installations (but not only) there is often no grounding available, or we may have a faulty installation where there are so-called leaks into the system (e.g. through a flooded outlet, chafed insulation, etc.). Grounding the installation is critical for the safe use of electric car chargers, and many chargers will block the ability to charge without properly functioning grounding. Most often, such protections can be disabled at your own risk, which is not recommended.
- appropriate protections - regardless of the protections built into the chargers, we recommend to each user to have an additional electrical circuit with protections for electric car charging: overcurrent circuit breaker (Ska/standard fuse), RCD type B (detecting residual DC current) or RCD type A with residual DC current detection adapted for EVs.
- Wiring and outlets - the outlet you want to use - whether a power or household outlet - should be adapted to the parameters of the charger. A description of the maximum supported current in V and A can usually be found on the outlet housing. The electrician should also verify the length and cross-section of the wires for the maximum load. Cables with too small a cross-section, or incorrect sockets can contribute to overheating and cause a fire.
