40 amp vs 48 amp charger for a GMC Sierra EV
For the trims below, EPA data shows the car accepts more than a 40 A charger delivers (9.6 kW). A 48 A charger (11.52 kW) saves up to about 3.5 hours on an empty-to-full charge (estimate). It needs a 60 A breaker instead of 50 A.
Per trim
| Trim | Empty→full at 40 A | Empty→full at 48 A | Miles per 8 h at 40 A | Miles per 8 h at 48 A | Why we think it accepts more |
|---|---|---|---|---|---|
| 2026 SIERRA EV Ext Range (11kW Charger) | 21.1 h | 18.4 h | 155 mi | 178 mi | EPA trim name states a 11 kW onboard charger |
| 2026 SIERRA EV Std Range (11kW Charger) | 14.8 h | 12.9 h | 153 mi | 175 mi | EPA trim name states a 11 kW onboard charger |
| 2026 SIERRA EV Ext Range (19kW Charger) | 21.0 h | 17.5 h | 147 mi | 176 mi | EPA trim name states a 19 kW onboard charger |
| 2025 Sierra EV | 21.3 h | 17.7–11.5 h | 147 mi | 176 mi (max) | EPA 240 V time implies an average of 17.8 kW, so it must accept more than 9.6 kW at times |
Estimates: energy for the full EPA range (kWh/100 mi × range ÷ 100, at the wall) ÷ charging power. Where EPA states the onboard charger we cap at it. Otherwise the 48 A figure is a range: from full 11.52 kW down to the average power implied by EPA's 240 V time, because the true onboard limit isn't in EPA data. Real charging tapers near 100%. Vehicle data: fueleconomy.gov.
Does it matter day to day?
Most drivers plug in overnight and rarely charge from empty. Both chargers add 155+ miles in 8 hours for the most efficient qualifying trim. The 48 A option mainly helps with long daily drives, short charging windows on time-of-use plans, or sharing one charger between two cars. The bigger circuit can cost more to install (wire size, panel capacity), and that cost isn't in our data.
Certified chargers at each size
ENERGY STAR lists 20 featured 40 A and 26 featured 48 A chargers: 40 A chargers · 48 A chargers · breaker sizes. Most can be set to a lower current if your panel can't supply 60 A.
All GMC Sierra EV charging times · Calculator
Not electrical advice; use a licensed electrician.