“How many kilowatts does it take to charge an electric car?” is one of the most frequently asked questions by those new to electric mobility, and there’s no single answer. The right power output depends onwhere you charge,how long the vehicle remains stationary, andhow much range you want to restore.
There is no one-size-fits-all solution: the best solution is the one that fits your specific situation. In this guide, we explain how charging power works, what it means in practice, and how to choose the most efficient setup.
What does “kW” mean in the context of charging?
Before answering the question, it’s helpful to clarify what the kW rating means in the context of electric vehicle charging.Kilowatts (kW)indicate thecharging power—that is, the rate at which energy is transferred to the vehicle’s battery. The higher the power, the faster the charging.
The basic formula is simple: multiplying the charging power (kW) by the charging time (hours) gives you the amount of energy transferred (kWh). An11-kWcharging station that charges for5 hourstransfers55 kWhof energy, which is enough to fully charge a medium-sized battery.
One key point to always keep in mind:the actual charging power is determined by the vehicle, not the charging station. If a car can accept a maximum of 11 kW of alternating current (AC), even if you connect it to a 22 kW charging station, it will charge at 11 kW. The charging station can deliver more power than the vehicle can accept, but the reverse is not true.
Charging speeds: from slow to ultra-fast
Charging Stations divided into three main categories based on their power output.
Slow AC charging AC 3.7–7.4 kW):This is the basic level, typical of household outlets with an adapter or entry-level wallboxes. At 7.4 kW, approximately59 kWh are transferredin 8 hours, which is sufficient to charge an average battery but not ideal for those with higher demands. It is suitable for very long stops, such as overnight stays.
Semi-fast AC charging AC 11–22 kW):This is the most common type in public and corporate settings. At11 kW, approximately88 kWh are transferredin 8 hours, which more than meets the needs of most vehicles. At22 kW, up to176 kWh can be transferredin 8 hours, but only if the vehicle is equipped to handle this power (many models accept a maximum of 11 kW in AC).
DC fast charging DC 50–150 kW):Direct current bypasses the onboard converter and charges the battery directly, allowing for much higher power outputs. At50 kW, an 80% charge of a 60 kWh battery is achieved in about60–80 minutes. At100–150 kW, this time is reduced to20–40 minutes.
Ultra-fast DC charging DC 150–400 kW):the most advanced level, found primarily on highways and at high-traffic hubs. It allows drivers to regain up to300 km of range in 15–20 minutesunder optimal conditions. However, it requires that the vehicle support these high power levels.
How many kilowatts do you really need? It depends on the situation
The right question isn’t “how many kW are best,” but “how many kW do I need for my specific use?” Here’s how to approach this for the main scenarios.
Overnight charging (8–12 hours available):in this case, even7–11 kWis more than enough. With 11 kW and 8 hours, up to 88 kWh can be charged—more than the battery capacity of most vehicles on the market. Higher power ratings offer no practical advantage: the vehicle finishes charging sooner and stops automatically.
Charging at the office or in a company parking lot (6–8 hours available):the same considerations apply. An11-kW wallboxmeets all needs. A22-kWwallbox makes sense only if your fleet includes models that support this power output and if you want to leave room for future use.
Charging at a shopping mall or supermarket (45–120 minutes):With shorter stops, power output becomes more important. A AC charging stationdelivers approximately 22–44 kWh in an hour, restoring 120–250 km of range depending on the vehicle.A 50–100 kWDC charger allows for more significant charging in the same amount of time.
Charging on the highway (15–30 minutes):Here, maximum power is essential. OnlyDC charging stationsDC 100 kW or higherallow you to regain enough range to continue your journey during a short stop. The higher the power, the more miles you can regain in the same amount of time.
The maximum power rating for vehicles: what to check
Every electric vehicle has two power limits that are important to know:
- Maximum AC alternating current) power:indicates how much power the onboard charger can handle. The most common values are7.4 kW(single-phase),11 kW(three-phase), and22 kW(three-phase, on premium models). Connecting an 11 kW vehicle to a 22 kW charging station makes no difference: it will still charge at 11 kW.
- Maximum DC direct current) power:indicates the maximum fast-charging rate that the battery can handle. This varies greatly between models: from50 kWfor more affordable vehicles up to350 kWfor the latest high-performance models. This information can be found in the vehicle’s technical specifications and should always be checked before choosing a charging station.
A handy formula for calculating the required kW
For those who want to make an accurate calculation, the formula is:
Power required (kW) = Battery capacity (kWh) ÷ Available charging hours
Here are some concrete examples:
| Battery | Available hours | Power required |
|---|---|---|
| 40 kWh (small city car) | 8 hours | 5 kW(a 7 kW wallbox is sufficient) |
| 60 kWh (mid-size sedan) | 8 hours | 7.5 kW(an 11 kW wallbox is ideal) |
| 80 kWh (average SUV) | 8 hours | 10 kW(an 11 kW wallbox is sufficient) |
| 100 kWh (premium SUV) | 8 hours | 12.5 kW(a 22 kW wallbox is ideal) |
| 60 kWh | 1 hour | 60 kW(requires a DC charger) |
⚠️These figures are approximate and refer to a full charge from 0% to 100%. In practice, charging almost always starts from a partial charge, which reduces the actual power required.
Is more kW always better?
Not necessarily. A power rating higher than what is needed for your specific use is a suboptimal investment. A 22 kW wallbox installed for a vehicle that can handle a maximum of 11 kW of AC practical benefit over an 11 kW model, but comes with higher hardware and installation costs.
The right choice is onethat takes into account the actual circumstances: the vehicle currently in use, the average duration of parking, and—with an eye to the future—the possibility of switching vehicles or increasing the number of charging stations installed.
For corporate installations or public parking lots, where a diverse fleet of vehicles is served, the logic changes: in that case, it makes sense to provide more power to meet everyone’s needs.
Choose the right power with Powy
Choosing the most suitable power configuration requires a technical assessment that takes into account the specific context, the vehicle fleet, and the available electrical system.
Powy its partners at every stage of the process, starting with the site survey, to identify the most efficient solution for each specific situation: from company parking lots to hospitality and commercial facilities, all the way to the most complex and multifaceted projects.
Are you considering how much charging capacity to install at your facility? Powy can helpPowy determine the most efficient configuration: AC charging stations AC 7 to 22 kW and DC and ultra-fast charging stations, with 24/7 operational management and flexible investment models, including options with zero CAPEX.
Contact us for a no-obligation consultation.
Disclaimer: These figures are approximate: power output and charging times may vary depending on the vehicle model and operating conditions (temperature, battery condition, available power). Always check your car’s specifications.
FAQ: Frequently Asked Questions About Charging Electric Cars
How many kWh does an electric car consume per 100 km?
Most electric vehicles on the market consume between 14 and 22 kWh per 100 km, with an average of about 16–17 kWh for mid-size models. The most efficient city cars consume less than 14 kWh, while large SUVs can exceed 20 kWh, especially on the highway or in unfavorable weather conditions.
About Powy
Powy a company that owns, develops, and manages Italy's leading independent network of public charging infrastructure for electric vehicles.
Founded in Turin, Italy in 2018, Powy is at the center of the transition to more sustainable mobility, offering an innovative charging infrastructure that uses only 100 percent renewable energy.
Powy 's network includes quick, fast, and ultra-fast charging solutions strategically placed in public and private parking lots, supermarkets, shopping malls, and transportation hubs to ensure maximum convenience and accessibility for EV drivers. Each station is equipped with advanced technologies to provide a reliable and efficient charging experience.
Learn more: wpowy.energy