Two EVs do not automatically need twice the grid capacity. Add their daily energy needs, compare that total with the hours both cars are parked, and coordinate charging within the home’s available power. One shared wallbox can work; two load-balanced wallboxes usually make changing drivers and priorities easier.
How much energy do two EVs need each night?
Calculate energy from distance and actual consumption. If one car travels 50 km at 18 kWh per 100 km, it needs about 9 kWh at the battery. A second travelling 80 km at 22 kWh per 100 km needs about 17.6 kWh.
50 × 18 ÷ 100 = 9 kWh
80 × 22 ÷ 100 = 17.6 kWh
Together that is 26.6 kWh battery-side. Add a transparent allowance for charging losses when sizing wall-side energy. Do not size every night as if both cars arrive empty unless that is a credible routine.
Can one wallbox serve two cars?
Yes, if both can reach it and somebody is willing to move the cable or cars. A single tethered unit is convenient when the charge ports are compatible and parking order is predictable. A socketed unit lets each vehicle use its own suitable cable.
One 7.4 kW wallbox can theoretically deliver 59.2 kWh over eight hours before losses:
7.4 kW × 8 hours = 59.2 kWh
That may cover both example cars comfortably. The inconvenience is human: the second car does not start until someone switches the connection. If departure times differ, charge the early car first and set a reminder.
When are two wallboxes worth it?
Two units are useful when both cars park in fixed spaces, arrival times vary or nobody wants a midnight cable swap. They also let a controller allocate energy automatically and keep per-car session records.
Do not assume each needs a separate full-power supply allocation. A coordinated pair can share a site limit. At low demand, one car can receive most available power. When both are connected, the controller can split or alternate it.
Check that the wallboxes actually support the same local or backend load-management system. Two Wi-Fi apps do not create electrical coordination.
How does load sharing work?
The controller holds combined charging within a configured limit. Equal sharing is simple, but priority rules can be more useful. The car leaving first might receive power until it reaches a target, then the second takes over.
Minimum AC charging current matters. If an equal split falls below what each car can accept, a good system may charge one at a time rather than repeatedly start and stop both. Phase use also matters when one vehicle is single-phase and another is three-phase.
Ask what happens if communication between wallboxes fails. A safe system should fall back to a defined limit rather than letting both draw their independent maximum.
How should household load be protected?
Dynamic load management measures or estimates building demand and reduces EV charging to preserve the main connection. This becomes more valuable with two cars, a heat pump, electric cooking, hot water or solar equipment.
The site limit must be commissioned from the real supply and protection. It is not the sum of charger labels. Measurement sensors, phase mapping and fail-safe behaviour need to be designed and tested.
Do not install the second charger as an isolated guess
Have the electrician assess both EV circuits and the whole-building load together. Copying the first charger installation can miss simultaneous demand, load-controller compatibility and changed protection requirements.
Do you need a larger grid connection?
Not always. First use time. If both cars sit for ten hours and need modest daily energy, a shared lower power can finish easily. Off-peak scheduling and load balancing may avoid an expensive connection change.
Consider an upgrade when combined daily mileage is high, parking windows are short, other electrical loads already consume the available capacity or the present phase arrangement prevents a workable allocation.
Compare the connection cost and ongoing tariff effects with the actual time saved. A 22 kW headline brings no benefit when both cars accept 11 kW AC and already finish overnight on less.
What if one car needs priority?
Define a rule everyone understands: earliest departure, lowest state of charge, work vehicle first or manual override for exceptional trips. The system should show which car is waiting and why.
Avoid a permanent priority that starves the second vehicle. A departure schedule with energy targets is more useful than simply giving charger A all available current.
Keep a manual fallback. If the smart controller is offline, each driver should know which connector can charge, at what safe fallback limit, and how to avoid both cars leaving short.
What is the sensible design path?
Measure each car’s weekly energy, map parking and departure windows, then calculate the shared power needed. Decide whether a cable swap is acceptable. If not, choose two compatible wallboxes under one load-management design.
The goal is not two maximum numbers on the wall. It is two ready cars every morning without asking the house connection to do two incompatible jobs at once.
Frequently asked questions
Do two EVs need two wallboxes?
No. One conveniently placed wallbox can be enough when cars arrive at different times or daily energy need is modest. Two wallboxes improve convenience and automated sharing, but they should be designed as one coordinated load rather than two unrelated maximum-power circuits.
Can two 11 kW wallboxes share an 11 kW site limit?
Yes when the products and controller support coordinated load management and the installation is designed for it. They can divide or alternate the available current. Confirm phase behaviour, offline fallback, minimum current and compatibility before assuming two branded chargers will cooperate.
Should I upgrade the grid connection for a second EV?
Only after calculating daily energy, dwell time and other building loads. Scheduling and dynamic load management can often use existing capacity. An upgrade may be justified for high daily mileage, short parking windows or other large loads, but it is not the automatic first step.
