Last updated: September 26, 2026 · ChargePapa Knowledge Hub
Rated charger power is a ceiling, not a promise. Actual AC speed is limited by the lowest-rated element: site voltage and phase, circuit, EVSE setting, cable/adapter path and the vehicle’s onboard charger; schedules and battery temperature can reduce it further.
What are the six common causes?
| Cause |
What it changes |
How to check |
| Vehicle onboard charger |
Maximum AC intake |
Vehicle specifications |
| Voltage/phase |
Available electrical power |
Site measurements |
| Circuit/EVSE current |
Safe continuous current |
Installation and settings |
| Schedule/charge target |
When and how long charging runs |
Vehicle and app timers |
| Temperature |
Vehicle conditioning and limits |
Ambient/battery status |
| Cable/adapter/voltage drop |
Path ceiling and losses |
Ratings, damage and under-load testing |
AFDC distinguishes Level 1 and Level 2 by the supply and equipment path. Source: AFDC home charging guidance. IEC 61851-1 covers EVSE connection, operating and safety requirements. Source: IEC 61851-1.
How should you calculate expected AC power?
For a simple single-phase estimate, power is approximately voltage × current. Three-phase calculations differ and require a compatible site, EVSE and vehicle onboard charger. Do not infer the circuit or phase from the connector alone.
What is the correct diagnostic order?
- Confirm the vehicle’s maximum AC intake.
- Confirm site voltage and phase.
- Confirm circuit and EVSE current settings.
- Disable overlapping schedules one at a time.
- Compare cold and mild-temperature sessions.
- Inspect the connector path and measure under load if qualified.
Which ChargePapa paths illustrate the distinction?
The V2 Type 2 socket wallbox offers 7kW, 11kW and 22kW paths, but 11kW/22kW require suitable three-phase supply and vehicle support. The MRS-AU is a North American J1772 path with 32A, 40A and 48A variants. Choose by site and vehicle, not the largest number.
Find the lowest ceiling first
Use the Buyer’s Guide after documenting supply, circuit, connector and vehicle limit.
What are the limitations?
This guide does not replace onsite voltage, phase or circuit verification and cannot predict DC fast-charging speed.
Frequently asked questions
Why does a 22kW charger deliver only 7kW?
The site or vehicle may be single-phase, or the vehicle onboard charger may accept only about 7kW AC. A 22kW EVSE rating does not create three-phase supply or increase the vehicle onboard charger limit.
Does the cable affect charging speed?
Yes. The cable, connector, adapter and current coding must support the path, but replacing them will not overcome the circuit or vehicle ceiling. Remove damaged or under-rated accessories from service.
Can low voltage reduce charging power?
Yes. AC power depends on voltage and current. Voltage drop under load can reduce delivered power and may indicate a long run, poor connection or supply issue that should be assessed.
When is the EVSE itself likely at fault?
Suspect the EVSE after confirming vehicle limits, schedule, temperature, circuit, voltage and accessory path. Error logs, repeatable behavior on a known-good installation and manufacturer diagnostics are stronger evidence than nameplate comparison alone.
