1. Which EV charger is the better choice?
At first glance, the 22kW unit appears to be the winner on paper, as its higher power reduces charging time. However, speed alone does not guarantee that it is the right charger for you. In the following sections, I will compare the two models from several angles, enabling you to determine which charger is best suited for your specific situation.
2. Key differences between 7kW and 22kW EV chargers
| Comparison Dimension | 7kW EV Charger | 22kW EV Charger |
| Power Supply Type | Single-Phase AC | Three-Phase AC |
| Typical Charging Speed | 30-50km/h | 90-150km/h |
| Home Electrical Compatibility | Can connect directly to an existing 220V single-phase supply | Requires a 380V three-phase supply; most homes need electrical upgrades |
| Installation Cost | $500 – $800 | $1,000 – $2,400+ |
| Typical Use Case | Overnight home charging, residential parking spaces | Commercial sites, workplace parking, multi-EV households, high-end residences |
| EV Compatibility | Compatible with almost all EV models | Only some models support three-phase charging |
2.1 Power supply
7kW EV charger: It uses a single-phase 220V/32A power supply, which is already available in most residences, making installation easy.
22kW EV charger: Requires a three-phase 380V/32A power supply. If the residence is not pre-equipped with three-phase electricity, an application for capacity expansion must be submitted to the power supply bureau. The renovation cost may be as high as $1500-4000, and the process may take a long time.
2.2 Charging speed
Because the power supply and internal design differ, the 22kW unit charges noticeably faster. A 7kW EV charger adds roughly 30-50 miles of range per hour. In contrast, a 22kW EV charger adds 90-150 miles in the same time. In other words, the 22kW unit can top up a battery three to four times faster.
2.3 Cost
The 22kW model requires more complex parts and stricter pre-conditions. Consequently, it usually costs more than the 7kW version. If you don’t need the extra speed and are sensitive to price, the 7kW EV charger offers better value.
Taking an 80kwh electric vehicle battery as an example:
If a 7kw EV charger is used, it takes approximately 11.5 hours to charge from 0% to 100%, which can be completed during nighttime sleep. The total installation cost is usually less than $800.
If a 22kw EV charger is used, the charging time can be shortened to within 4 hours. However, if the household does not have three-phase electricity, circuit modification is required, and the total investment may exceed $2,000.
Therefore, for users with an average daily driving distance of ≤80km, charging at night with a 7kW charger fully meets their needs and offers a higher cost-performance ratio.
2.4 Typical use cases
Single-phase circuits are common in homes, and 7kW charging is gentle enough for overnight top-ups. Thus, the 7kW EV charger fits most residential settings. It can also serve light commercial use. Three-phase circuits, on the other hand, are standard in offices, shopping malls, and large parking lots. In these high-traffic areas, drivers want quick turnaround, so the 22kW EV charger is the preferred choice. A few homes with three-phase supply can also use it, but this is rare.
2.5 Vehicle compatibility
Charging speed is not only about the charger. The onboard charger (OBC) inside the car matters too. Many cars cannot accept three-phase power or limit the current to a lower level. In such cases, a 22kW EV charger will not deliver its full power, and the session may run no faster than with a 7kW unit. Before you purchase, check your car’s specifications or ask the manufacturer to confirm compatibility.
3. Common questions
3.1 Can I connect a 7kW charger to a 22kW three-phase supply?
Technically feasible, but it is not recommended. Although it can be used through conversion, the actual charging power remains at 7kW due to the limitations of the on-board charger in the vehicle. During use, there is a voltage mismatch, and the neutral current may be overloaded by 2-3 times, leading to overheating of the circuit, causing circuit breaker tripping or fire hazards. Professional installation should follow the “charging station-vehicle-power” matching principle.
3.2 How do I install an EV charger legally?
First, you need to own or control the land and have a parking space near the road. The site must also have a reliable internet signal. Next, hire an authorized and reputable installer. The work must comply with local building codes and national electrical standards. Finally, obtain approval from the local Distribution Network Operator (DNO) before the unit is connected to the grid. Once these steps are complete, your charger will operate safely and legally.
4. Conclusion
After reviewing the differences, advantages, and limitations, it becomes clear that neither charger is inherently better. Each one serves a distinct need and environment. If you are thinking about purchasing an EV charger or have any related questions, please contact JMHPOWER. We will be happy to assist you.
