Choose the setting in two moves. First, the circuit sets the ceiling: never exceed what it can carry continuously. Then the clock picks the step — how much energy you need, divided by the hours the car is parked. On its home turf — a NEMA 14-50 outlet on a 50 A circuit — the ceiling is the full 40 A; the steps below it exist for the hours when less fits better.
Key Takeaways
- The circuit sets the ceiling first: each setting pairs with a breaker at 125% of its current, and the charger must never exceed its circuit.
- On a 50 A NEMA 14-50 circuit, all four EV-ACS4005T settings are legitimate — the clock then picks the step.
- Overnight, a lower step usually finishes anyway; 40 A is for short windows and low batteries.
- A lower setting changes the rate, not the total energy the car takes.
Step One: The Circuit Sets the Ceiling
EV charging is a continuous load, so the National Electrical Code sizes the breaker at 125% of the charging current. The rule pairs each step with its circuit:
| Setting | Output at 240 V | Breaker it pairs with (125%) | Where that leaves it |
|---|---|---|---|
| 16 A | 3.8 kW | 20 A | Well under a 50 A circuit’s ceiling |
| 24 A | 5.8 kW | 30 A | A gentle overnight rate on the same outlet |
| 32 A | 7.7 kW | 40 A | The rate many cars top out at anyway |
| 40 A | 9.6 kW | 50 A | The full step a 14-50 circuit is for |
Plugged into a healthy 14-50 circuit, all four settings are inside the ceiling, and 40 A is a legitimate everyday choice. The table matters when an electrician says the circuit behind an outlet is smaller than the outlet suggests: then the pairing, not the plug shape, picks your step. Our breaker size guide and explainer on what a NEMA 14-50 outlet is cover the circuit side. One rule outranks the rest: never set the charger above what its circuit supports.
Step Two: The Clock Picks the Step
Work backwards from the morning. Say the car needs 30 kWh back and sits eight hours: even the 16 A step delivers roughly that (3.8 kW × 8 hours ≈ 30 kWh, before losses), so higher steps only buy an earlier finish. Shrink the window and the same 30 kWh in four hours needs the 32 A step (7.7 kW × 4 ≈ 31 kWh); a low battery before an early start is what 40 A is for. The setting is a dial: many owners run a lower default and turn it up when range matters.
Good Reasons to Run Below the Ceiling
- A busy evening panel. Cooking, heating and laundry peak at once. A 24 A draw leaves the rest of the house more headroom than a 40 A draw, and the car still finishes overnight. Our guide to what size charger a panel can support shows the totals.
- Solar on the roof. A smaller array’s surplus is modest and variable; a lower step lets the car take what the roof is making instead of pulling the difference from the grid. Our solar panels and EV chargers guide covers the matching.
- Long stays. A car parked all weekend gains nothing from finishing on Friday night. The gentlest step that covers the next drive is enough.
The Charger in Brief
The EVDANCE EV-ACS4005T is a 40 A NACS portable charger: 9.6 kW maximum, settings at 16/24/32/40 A chosen on the unit, a NEMA 14-50P plug, an IP66 enclosure and a 25 or 28 ft cable. Because it is portable, the ceiling travels with the outlet — which is why the two-step choice is worth learning once. If your circuits top out lower, its sibling, the EV-ACS3210T, adjusts from 10 A to 32 A in six steps instead.
Frequently Asked Questions
Does a lower setting use less electricity overall?
About the same: the car needs the same kWh for the same miles, delivered over a longer session. The setting changes the rate, not the total — it is about fit and timing, not energy saved.
Can I change the setting myself?
Yes — on this portable unit the steps are set on the charger, within the range it offers. On a hardwired wallbox, the maximum is set at installation to match its circuit — the installer’s to change, not the owner’s.
Which setting should I leave it on?
The lowest one that finishes before you leave. For many overnight routines that is 24 or 32 A; keep 40 A for short windows and low batteries. If unsure what your circuit supports, ask a licensed electrician before using the top step — not after a breaker complains.
Related Reading
- What Size EV Charger Can I Have at Home? Panel Capacity Explained
- What Size Breaker Do I Need for an EV Charger?
- What Is a NEMA 14-50 Outlet? A Guide for EV Owners
- Solar Panels and EV Chargers: How to Charge Your Car With Sunshine
