E-Mobility
EV Charging Reference
AC/DC charger power tiers and charge rates, the German 11/22 kW grid-connection rule, simultaneity factor guidance for multi-point sites and IEC 61851 charging modes. Use alongside the EV Charging Calculator.
Last updated: July 2026
Terms
- IECInternational Electrotechnical Commission
- The international body that writes electrical safety standards used across most of the world outside North America. When a chart cites an IEC number, it's pointing to the official rulebook behind a calculation.
- VDEVerband der Elektrotechnik Elektronik Informationstechnik
- The German electrical engineering association that publishes widely-used safety standards in Germany and beyond — similar in role to IEC, but specifically German.
Charger Power Tiers
Effective charge rate accounts for typical charging efficiency (88 % AC, 93 % DC). The "40 kWh" column is a linear estimate — real DC fast-charging slows well before 100 % as the battery management system tapers current, especially above ~80 % state of charge.
| Tier | Connector | Effective rate | 40 kWh (linear estimate) | Typical use |
|---|---|---|---|---|
| AC 3.7 kW | Type 2 | 3.3 kWh/h | 12h 17m | Single-phase home outlet-class wallbox |
| AC 7.4 kW | Type 2 | 6.5 kWh/h | 6h 09m | Single-phase wallbox, overnight home charging |
| AC 11 kW | Type 2 | 9.7 kWh/h | 4h 08m | Most common home/workplace three-phase wallbox |
| AC 22 kW | Type 2 | 19.4 kWh/h | 2h 04m | Faster wallbox — needs a car with 22 kW onboard AC charger to benefit |
| DC 50 kW | CCS | 46.5 kWh/h | 52 min | Entry-level public fast charging |
| DC 150 kW | CCS | 139.5 kWh/h | 17 min | Highway / rapid public charging |
| DC 350 kW | CCS | 325.5 kWh/h | 7 min | Ultra-fast charging — few vehicles can accept the full rate |
Grid-Connection Rules (Germany)
Applies to AC wallboxes only — DC fast chargers are treated as commercial connections and always require network-operator coordination.
| Wallbox power | Requirement | Reference |
|---|---|---|
| ≤ 11 kW | Anmeldepflichtig — notify the network operator | §19 NAV / VDE-AR-N 4100 |
| > 11 – 22 kW | Genehmigungspflichtig — approval required before install | §19 NAV / VDE-AR-N 4100 |
| > 22 kW AC / DC | Treat as commercial connection | Network operator coordination |
Notification/approval timelines and forms vary by network operator (Netzbetreiber) — confirm the current process before ordering equipment.
Worked Example — Home Charging
Battery: 75 kWh. State of charge: 20 % → 80 %. Charger: 11 kW AC wallbox. Vehicle onboard charger: 11 kW. Efficiency: 88 %. Electricity price: €0.35/kWh.
Step 1 — Energy to battery: 75 kWh × (80 % − 20 %) = 45.0 kWh
Step 2 — Effective power: min(11 kW wallbox, 11 kW onboard) = 11.0 kW
Step 3 — Charging time: 45.0 kWh ÷ (11.0 kW × 0.88) = 4 h 39 min
Step 4 — Energy from the wall: 45.0 kWh ÷ 0.88 = 51.1 kWh
Step 5 — Cost: 51.1 kWh × €0.35/kWh = €17.90
Grid note: 11 kW is ≤ 11 kW → anmeldepflichtig only, no approval needed.
Simultaneity Factor Guidance (Commercial Sites)
Not every charge point draws full power at the same time. The simultaneity factor (Gleichzeitigkeitsfaktor) scales installed capacity down to a realistic required grid connection.
| Charge points | Typical simultaneity factor | Rationale |
|---|---|---|
| 1 – 2 | 0.9 – 1.0 | Both/all points can realistically charge at once |
| 3 – 5 | 0.7 – 0.85 | Occasional overlap, still fairly likely |
| 6 – 10 | 0.5 – 0.7 | Statistical spread of arrival/departure times begins |
| 10+ | 0.3 – 0.5 | Large fleet/site — full simultaneous draw is very unlikely |
IEC 61851 Charging Modes
| Mode | Description | Typical connector |
|---|---|---|
| Mode 1 | Direct connection to a standard socket, no in-cable control | Domestic plug (not recommended for EVs) |
| Mode 2 | Standard socket with an in-cable control box (IC-CPD) | Domestic/industrial plug |
| Mode 3 | Dedicated AC wallbox with control/communication pilot | Type 2 (IEC 62196) |
| Mode 4 | DC fast charging, off-board charger converts AC→DC | CCS / CHAdeMO |
Frequently Asked Questions
Why is DC charging time in the table "linear" and not exact?
Real EV battery management systems taper charging current as state of charge rises — DC fast charging is fastest from roughly 10–60 % SoC and slows considerably above 80 %. A linear kWh/h estimate is accurate for planning a top-up in the fast-charging range, but will understate real time for a full 0–100 % charge.
Does the 11/22 kW rule apply to DC chargers too?
No — §19 NAV's simplified anmeldepflichtig/genehmigungspflichtig thresholds are for AC wallboxes. DC fast chargers, by their power level and site type, are treated as commercial grid connections requiring direct network-operator coordination regardless of the specific kW rating.
What if my vehicle's onboard charger is lower than 11 kW?
Charging speed on AC is capped at the lower of the wallbox and the vehicle's onboard AC charger — a 7.4 kW-onboard vehicle on an 11 kW wallbox still charges at 7.4 kW. Check the effective-power output on the EV Charging Calculator, which applies this limit automatically.
How conservative should the simultaneity factor be for a new site?
For a brand-new site with no usage data, start conservative (the higher end of the range for the point count) and plan for load management (Lastmanagement) that can dynamically share capacity across points — this avoids under-provisioning the grid connection while still allowing headroom as usage patterns emerge.