AltLevel 1, Level 2, and DC fast charging
Three names for what are really only two different things — and knowing which is which explains why a generator can do one of them and not the other.
The actual distinction
Levels 1 and 2 are both AC charging. The wall unit is not a charger at all; it's a safety-and-signalling device that switches AC through to the car. The real charger lives inside the vehicle, and its size sets your ceiling no matter what you plug into.
DC fast charging skips that entirely. The charger is the giant cabinet at the roadside, and it feeds DC straight to the pack, bypassing the onboard unit. That's why it's an order of magnitude faster and why it costs what it costs.
| Level 1 | Level 2 | DC fast | |
|---|---|---|---|
| Supply | 120V AC | 240V AC | 400–900V DC |
| Typical power | 1.4–1.9 kW | 7–11 kW | 50–350 kW |
| Range per hour | 3–5 mi | 25–40 mi | 200–1000 mi |
| Charger location | In the car | In the car | In the cabinet |
| Install cost | $0 | $400–2,000 | $50,000+ |
| From a generator? | Easily | Yes, derated | No |
Level 1: the outlet you already have
A standard 120V household outlet. Roughly 3–5 miles of range per hour, which sounds useless until you notice it's 40–60 miles overnight — more than most people's daily driving. If you commute under 40 miles a day, Level 1 genuinely covers it and the correct install cost is zero.
Where it fails is recovery. Come home empty and you're not going anywhere tomorrow.
Level 2: what most people should install
240V, typically on a 40 or 50A circuit, giving 7–11 kW. A full overnight charge from nearly empty, every time. This is the sweet spot for home charging and the only level worth paying an electrician for.
Your ceiling is the car's onboard charger, not the wall unit. If your vehicle tops out at 7.7 kW, an 11 kW wall unit buys you nothing.
DC fast charging: for trips, not for home
The roadside cabinets. Enormously fast, and not something any home or generator setup can replicate — a single 150 kW stall draws more power than twenty houses. Anyone selling you a "home DC fast charger" is selling you something else.
Worth knowing: fast charging tapers hard as the pack fills. The headline rate applies at low state of charge and drops sharply past about 80%, which is why road-trip advice is to charge in short bursts rather than to full.
Where a generator lands
A generator supplies AC, so it can do Level 1 and Level 2 — never DC fast charging.
- Level 1 from a generator: trivially easy. Almost anything with a 120V outlet and clean power will do it, at 3–5 miles per hour.
- Level 2 from a generator: the useful case. Needs 240V, an inverter generator, and derating for continuous load — realistically 16–32A rather than a full 48A.
Work out your rate from a generator → · Why it has to be an inverter → · Why it won't start without a bonding plug →