EV Charging · Smart charging
Every home or business connected to the electrical grid has a limit to how much current it can import. Charging one or more EVs can draw a lot of current, so it's important that the total grid current, EV charging plus everything else in the building, never exceeds that limit. Overload protection is what makes sure of that automatically.
What you need
- EV Wall (Home) has the hardware to measure the grid built in.
- Any charging station that isn't a Home version needs a separate Smappee Infinity installation to measure the grid.
- Dashboard: Circuit configuration card > Grid > Maximum current
- App: Settings > Smappee monitors > Circuit configuration > Grid > Maximum current
How do I activate overload protection? How can I change my max grid current?
The 10% safety margin
Overload protection always applies a 10% safety margin to prevent tripping your circuit breaker. For example, with 63A available on the grid connection, Smappee will adjust the charging speed of active sessions to keep the grid current under 56.7A. That margin gives the system enough headroom to react to a short peak from other appliances, without ever tripping the breaker.
Why charging speed depends on how the car connects
Measurements and the algorithm work per phase, but almost all EVs communicate using the IEC 61851 protocol, which only allows sending one setpoint to the car. Smappee can't send a different current limit per phase, and can't tell the car how many phases to use, it simply provides all 3 phases and the car decides whether it uses 1, 2, or 3 of them.
At the start of every session, the car is briefly allowed to draw full power (within the installation's limits) for a few seconds, this is how Smappee detects how many phases the car uses and its maximum current. That information is then remembered for the rest of the session. For example, a single-phase EV using only L1 only needs to be limited based on what's available on L1, L2 and L3 aren't relevant to that session.
With more than one charging station on site, using phase rotation during installation is recommended. Read more about phase rotation.
When there isn't enough current for everyone
If there isn't enough current available to give every connected EV at least its 6A minimum, some sessions are paused until more current becomes available. Which sessions get paused first is based on priority, which you can assign:
- Per username, if Scan and charge is used.
- Per RFID token, if Swipe and charge (free) is used.
- As a default priority for unrecognised users.
Example: at a business site, you could give visitors a higher priority than employees. Employees are usually parked for longer, so they can afford to charge slower or later, while visitors need to charge faster during their shorter stay.
Requires a stable internet connection
For the Smappee EV Line, overload protection runs in the cloud, so both the charging station and the Infinity installation (where applicable) need a reliable internet connection for it to work.
My charging isn't behaving as expected
| What you see | Likely explanation |
|---|---|
| Maximum current field is empty | Overload protection isn't active, and Solar charging/Schedules won't work either. Fill it in based on the site's actual main breaker rating. |
| Maximum current is filled in, but doesn't match the real installation | Misconfigured, correct it to match the real breaker rating (confirm with your installer or electrical plan if unsure). |
| Charging slows down, or a session pauses, even though everything looks correctly configured | Expected: either the 10% safety margin is doing its job, or a lower-priority session is being paused because there isn't enough current for everyone. Not a fault, consider setting priorities per user/RFID token. |
| Non-Home charging station with no separate Infinity grid measurement installed | Overload protection can't function without a grid measurement. This is an installation gap, not a misconfiguration, ask your installer about adding Infinity. |
| Charging station is offline, with offline charging enabled | Cloud-based overload protection no longer applies while offline. Keep your failsafe current set to a low value (e.g. 6A) to stay safe in the meantime. |