EV charging levels explained: L1, L2 and DC fast

EV charging is described in "levels", which sounds like a difficulty setting and is really a distinction between two different jobs. Levels 1 and 2 deliver alternating current to the car and let the car convert it. DC fast charging does the conversion in the cabinet and feeds the battery directly. Everything else follows from that split.

The three tiers

The onboard charger: the limit nobody checks

On AC, the car's own onboard charger does the conversion, and it has a fixed ceiling — commonly 7.4 kW single-phase, 11 kW where three-phase is available, and occasionally 22 kW. Plug a 7.4 kW car into a 22 kW post and you will charge at 7.4 kW all night. The post is fine; the car is the bottleneck.

This is the single most useful specification to look up before buying a wallbox. Installing an 11 kW unit for a car that can only take 7.4 kW buys you nothing today, though it does future-proof the wiring for the next car. Run both scenarios through the charging time calculator and see whether the difference actually changes your mornings.

Why DC sessions slow down

A DC charger does not hold its peak. Cars accept full rate up to roughly 50–60% state of charge, then step down progressively to protect the cells, and above 80% the rate collapses. A 10–80% session might take 25 minutes while the final 20% takes nearly as long again.

Hence the road-trip rule: arrive low, leave at 80%, stop twice rather than once. You spend all your plugged-in time in the fast part of the curve. Cold packs charge slowly too, which is why cars with battery preconditioning warm the pack while navigating to a charger.

Connectors, briefly

• Type 2 (Mennekes): the AC standard across Europe, and the AC half of CCS2.
• J1772 (Type 1): the AC standard in North America and Japan.
• CCS: DC fast charging — CCS1 in North America, CCS2 in Europe. The dominant DC standard.
• NACS: Tesla's connector, now adopted by most manufacturers in North America, handling both AC and DC.
• CHAdeMO: the legacy Japanese DC standard, still on older Nissan Leafs and older chargers.

What this costs to run

Home charging at an overnight tariff is the cheapest energy any vehicle can buy — often a quarter of the day rate and a fraction of public DC pricing, which typically runs two to four times home rates. Charging losses of 8–15% apply on AC, so you pay for slightly more than the battery receives.

For a 60 kWh car doing 15,000 km a year at 18 kWh/100 km, that is 2,700 kWh into the battery, about 3,000 kWh from the meter. At 0.30 per kWh it is roughly 900 a year — against perhaps 2,000 in petrol for the same distance. The EV versus petrol calculator will do it with your own numbers and tariff, and the CO₂ savings calculator covers the emissions side of the same switch using your own grid.

Practical advice

1. Check your onboard charger rating first. It caps everything you do at home.
2. Install Level 2 if you can. It transforms EV ownership more than any other single purchase.
3. Set a daily charge limit of 80%. Same chemistry, same reasoning as a scooter pack; save 100% for trip days.
4. Use DC for journeys, not habit. Occasional fast charging is harmless; exclusive fast charging measurably ages the pack.
5. Charge on the cheap tariff window. The saving dwarfs every efficiency tweak available to you.