How to Set the Amps on Your EV Charger

Set the charger to 80% of its breaker, and never higher. A 40-amp breaker means 32 amps; a 50-amp breaker means 40; a 60-amp breaker means 48. That is NEC 625.42 treating EV charging as a continuous load and requiring the circuit to be rated at 125% of the charger's output — the same rule from the other direction. Your car's capability is irrelevant to this number, and raising the setting does not make the wire in your wall any thicker.

This is the step that gets skipped, and the reason the question gets searched so often is that adjustable chargers ship at a factory default. That default may be lower than your circuit allows — so you are charging slower than you paid for — or higher than it allows, which trips breakers and is genuinely unsafe. Either way, somebody has to set it, and on a plug-in install that somebody is usually you.

The number you need, in one table

Find your breaker in the left column. That row is your answer. Nothing about the car changes it:

Range figures assume roughly 3 miles per kWh, which is a reasonable average; your car will differ. The wire size and breaker guide pairs each of these with the conductor size it needs, and what amp charger do I need covers choosing the circuit in the first place.

Where the setting lives

There are three mechanisms, and which one you have changes the procedure:

• In the app. ChargePoint and Emporia-style units set the maximum current in their mobile app during setup, often by asking what breaker the charger is on and deriving the limit for you. Convenient, and worth re-checking after a firmware update or a factory reset — a reset can return the unit to its default.
• A physical selector inside the unit. Some chargers use a DIP switch or rotary selector behind the cover, set once at installation. This is the method the code contemplates for equipment whose rating depends on a restricted-access setting: it cannot be changed casually, which is the point.
• By the plug or installer configuration. Some units derive their limit from the plug fitted or from a setting the installer selects at commissioning. If an electrician hardwired your charger, this was their job — but confirm the number with them rather than assuming.
• On a portable, usually on the unit. Adjustable portables such as the WOLFBOX (6–40A) and Lectron NACS portable (8–40A) set current with a button or on a small display — which is exactly why they suit travel, where every outlet is different.

Your manual is authoritative for your model; the above is the shape of the thing, not a substitute for it. Also: your car may have its own charging-current limit in its settings. That is a separate control and it can only reduce the rate further — it cannot override the charger, and it is a frequent cause of unexpectedly slow charging.

How to check you got it right

• Watch the delivered power, not the setting. Your car or the charger app reports kW while charging. Compare it to the table above. If the breaker is 50 amps and you are seeing roughly 9.6 kW, you are correct; 7.7 kW means you are set to 32.
• Charge a full session and feel the receptacle. On a plug-in install, after an hour the plug should be warm at most. Hot, discolored or smelling of plastic means stop, step the current down and get the receptacle inspected.
• If the breaker trips, do not just reset it. Repeated trips at a setting the table says is fine point at the circuit, the GFCI or the charger — work through charger tripping the breaker.
• Re-check after any reset or firmware update. Especially on app-configured units. This is a 30-second check worth repeating.

When to deliberately set it lower

Lower than the maximum is sometimes the right answer, and it costs you very little:

• An outlet you do not know — travel, an old garage, a relative's house. Set conservatively; you can always step up.
• A tight panel. Reducing the charging current reduces the load the service has to carry, which can be what makes the install work at all. See best chargers for a 100-amp panel.
• Overnight is long anyway. At 32 amps a ten-hour window adds roughly 230 miles. If your daily drive is nowhere near that, the lower setting is free — the argument of the 32-amp roundup.
• A shared or guest charger where you want to cap exposure — see chargers for an Airbnb.

Chargers with a published adjustable range

If you are reading this page because your charger has no setting to change, that is the real answer. These are the units whose manufacturers publish a range rather than a single output — specs from the live listings, with live prices:

#ad Prices read live from the Amazon Product API as of October 16, 2026, and they move. Specs are the manufacturer's published claims from the live listing — we have not bench-measured them. Where we have no verified price we print none rather than a number that has gone stale.