Selecting an AC charging station for your electric car doesn't necessarily mean that you need to go for the fastest charging station or the one that is capable of providing high-power units. In fact, your decision must be influenced by your vehicle's capacity, available capacity at your property, and other aspects.
If you are planning to install a charging station at your house, in an apartment building, or in any commercial establishment, knowing these aspects might save you from making some unnecessary purchases. This guide discusses all the important aspects that will help you select the right AC charging station.
1. Understand Your EV's AC Charging Capacity
Before buying a charging station, find out about your EV's maximum AC charge capability. This tells you how much AC power your car can receive through its onboard charger.
While a DC charger feeds the battery with direct current, an AC charger provides the onboard charger with alternating current, and the onboard charger converts that power into DC for battery charging.
An EV may have a maximum AC charge capability of 7.4 kW, 11 kW, or 22 kW. Having a powerful charger installed won't necessarily make charging faster if your car is unable to receive the required amount of power.
For example, an EV with an onboard charger of 11 kW will receive no more than 11 kW of power even from a 22 kW AC charging station that is compatible with it.
What to check: Look at your car manufacturer’s specifications regarding the maximum AC charging power, number of phases used, connector type, and charging current.
2. Match the Charging Station to Your Electrical Supply
The electrical capacity of your property is one of the key considerations for choosing the AC charging station.
The power of the AC charger can be calculated according to these formulas:
- Single Phase: Voltage x Current ÷ 1,000 = kW
- Three Phase: Voltage x Current x Phases ÷ 1,000 = kW
In the case of a standard 230V phase-to-neutral input voltage, the three-phase formula can also be written like this: 230V x Current x 3.
Some examples are given below:
| Configuration | Approximate Charging Power |
|---|---|
| Single-phase, 230V, 16A | 3.7 kW |
| Single-phase, 230V, 32A | 7.4 kW |
| Three-phase, 230V, 16A | 11 kW |
| Three-phase, 230V, 32A | 22 kW |
Note: These are theoretical levels of power based on the given electrical specification. The power at which a vehicle will be charged depends on the equipment specifications, electrical supply, and requirements of the electricity.
The Type 2 AC charging connection allows for a maximum of 22 kW under a suitable three-phase system. However, there is a need to check whether the property's electrical supply is capable enough to carry the load.
For example, if your property does not have much power available, then you will be required to reduce the amount of power needed by the charging station, which in this case is 22kW.
3. Consider Single-Phase vs. Three-Phase Charging
Selecting single-phase or three-phase charging will depend on the electrical infrastructure of your place, vehicle compatibility, and specific needs for charging.
Single-phase charging can work well for people charging cars overnight and those who drive less. It can also work well if you do not have three-phase power available.
Three-phase charging can offer you high AC charging power if you have all the required equipment. It can work well for businesses, commercial parking places, and locations where cars stay parked only for a certain period of time.
Keep in mind that having three-phase EV charging stations does not necessarily mean you can use three-phase charging. It depends on the ability of your car to work in this mode and the proper provision of electrical supply.
Household socket outlets usually offer you single-phase electricity, which is different from dedicated EV charging. AC charging stations are a good alternative in this case after a professional assessment.
4. Calculate Your Expected Charging Time
Knowing the basics of charging time gives you insight into whether you really need an efficient AC charging station.
One basic calculation is:
Charging Time (hours) = Energy Needed (kWh) ÷ Charging Power (kW)
In this example, if your EV needs 22 kWh of energy and charging power is 11 kW, charging time will be about two hours. However, this is only a rough estimation, which doesn’t take into account some factors, like energy losses due to conversion, variable charging power, battery temperature, and charging near a high state of charge.
Moreover, one should differentiate between battery capacity and energy needed for a particular charging station. Just because the battery capacity is 60 kWh, it doesn’t mean that the EV needs 60 kWh each time you plug in.
Sometimes it might be more cost-efficient to charge your vehicle at a lower power level during the night rather than paying for an installation that you’ll use rarely.
5. Identify the Charging Bottleneck
The maximum charging speed will depend on the weakest limit across your electricity supply, charging station, cable, and vehicle.
For example:
- Suppose the maximum your property can offer is 22 kW, while your charging station has a rating of 7.4 kW. You can only charge at 7.4 kW.
- The maximum your charging station can offer is 22 kW, but your vehicle can charge at a rate of 11 kW. In such a case, you will be restricted to 11 kW.
This is how the maximum charging rate can be affected by various factors mentioned above. These are the reasons why getting the highest-rated items may not necessarily be the best option.
Make sure you check the amperage, vehicle charging capacity, charging station rating, and cable specifications before making a purchase.
6. Evaluate Essential Charging Station Features
Along with the charging capacity, think about the features that would make the charging experience convenient, safe, and reliable. Blaupunkt’s AC charging stations can be a practical choice when their specifications, protection features, and charging capabilities align with your property's requirements.
Electrical Safety: Review the electrical safety measures in terms of the protection features, residual current protection arrangement, earthing needs, and electrical compliance with the standards. The installation should take into account all requirements of the manufacturer and the relevant regulations.
Dynamic Load Management: This function allows for adjustment of the charging power depending on the property's electricity usage and the available capacity. It may help prevent any overload of the electricity supply system if installed and configured correctly.
Smart Charging: Features such as scheduling, charging reporting, app control, and energy monitoring may facilitate everyday use. Also, consider OCPP compatibility in case the property plans to connect chargers to a charger management system.
Weather Protection: In case of installations exposed to heat, dust, humidity, or outdoors, consider the IP rating, operating temperature range, resistance to UV, and installation possibilities. Thermal performance and environmental resistance in the UAE climate deserve special consideration.
Connector and Cable Compatibility: Make sure the connector fits your vehicle and that the cable capacity, length, installation requirements, and costs meet your needs.
7. Assess Installation, Costs, and Future Needs
Purchase cost is just one aspect of the whole EV charger installation cost. Electrical upgrades, cable lengths, mounting, protection, and labor costs involved in the installation may influence the total investment.
Where apartments, residential complexes, office premises, and commercial spaces are concerned, get your approvals sorted for building management, electrical capacity, metering, and the necessary installation permits beforehand.
Then you need to consider future requirements as well. In case you plan to buy another electric car or install a charging facility for the workplace in the future, go for an installation that allows for easy installation of charging points at a later stage without having to upgrade unnecessarily.
But that does not mean that you should overspend on power that you will never require. A properly sized AC charging station with suitable load management can provide a more balanced solution.
Conclusion
Choosing an appropriate AC charging station should begin with understanding the onboard charger of your vehicle as well as the electricity capacity available on the property. Factors such as charging power, compatibility, convenience, and installation cost are part of creating a satisfactory charging experience.
It would be better to select a charging station that suits your needs rather than opting for a wallbox charger with the highest power output.