How does the calculator know the charging power curve?

Once you pick a model from the EvCompass catalogue, its usable battery capacity and charging power curve fill in automatically — there is no spec to type in yourself.

Why does the post I pick change the time so much?

A post never delivers more power than its own rating, even when the car's curve would allow more at that moment. On a 50 kW post, a car capable of 150 kW still charges at a speed capped at 50 kW for the whole session.

Is the power curve measured by the manufacturer?

No. When the curve is calibrated, it means we shaped it to match ONE claimed figure from the manufacturer's own data (e.g. 85 kW, 0-80%, 35 min) — that is one data point, not a measured charging run. Where no such figure exists, the curve is entirely estimated from the car's specs instead. Neither one is a measurement.

EV calculators

Charging time

Pick a model from the catalogue, set the charge window, and see how long the session actually takes at a given charging post's power.

Start of charge (%)

The state of charge you start the session from.

End of charge (%)

The state of charge you end the session at.

Charging post power

The post's maximum rated power — the car never draws more than this, even where its own curve would allow it.

Custom station power (kW)

Enter the station's real rating if it differs from the three typical values above — e.g. the power printed on a specific charger's spec sheet.

XPENG X9 FWD Standard Range (2026) · curve calibrated to the claimed window 537 kW, 10–80%, 12 min

Charging time: 22 min
Energy delivered: 55.8 kWh
Average power: 150 kW
Range added: 279 km

curve calibrated to the claimed window 537 kW, 10–80%, 12 min

Car's own power curve
Power delivered at this post

The car's own power and the power actually delivered at the chosen post, by state of charge
State of charge	Car's power	Delivered power
10%	513 kW	150 kW
14%	513 kW	150 kW
17%	513 kW	150 kW
21%	513 kW	150 kW
24%	513 kW	150 kW
28%	479 kW	150 kW
31%	446 kW	150 kW
35%	412 kW	150 kW
38%	378 kW	150 kW
42%	345 kW	150 kW
45%	311 kW	150 kW
49%	302 kW	150 kW
52%	293 kW	150 kW
56%	284 kW	150 kW
59%	275 kW	150 kW
63%	266 kW	150 kW
66%	254 kW	150 kW
70%	241 kW	150 kW
73%	229 kW	150 kW
77%	216 kW	150 kW
80%	203 kW	150 kW

Charging time FAQ

How does the calculator know the charging power curve?: Once you pick a model from the EvCompass catalogue, its usable battery capacity and charging power curve fill in automatically — there is no spec to type in yourself.
Why does the post I pick change the time so much?: A post never delivers more power than its own rating, even when the car's curve would allow more at that moment. On a 50 kW post, a car capable of 150 kW still charges at a speed capped at 50 kW for the whole session.
Is the power curve measured by the manufacturer?: No. When the curve is calibrated, it means we shaped it to match ONE claimed figure from the manufacturer's own data (e.g. 85 kW, 0-80%, 35 min) — that is one data point, not a measured charging run. Where no such figure exists, the curve is entirely estimated from the car's specs instead. Neither one is a measurement.

Result

Charging time FAQ