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EV charging time

Plan a session length given battery capacity, charger speed and starting / target SoC. The model captures the dominant real-world effects — taper above 80%, cold-weather throttling, and efficiency losses.

Inputs

Time 20→80%

20 min

Energy added

45.0 kWh

Average effective rate

138 kW

5%-SoC steps

RangeEffective kWStepCumulative
20–25%1382 min2 min
25–30%1382 min3 min
30–35%1382 min5 min
35–40%1382 min7 min
40–45%1382 min8 min
45–50%1382 min10 min
50–55%1382 min11 min
55–60%1382 min13 min
60–65%1382 min15 min
65–70%1382 min16 min
70–75%1382 min18 min
75–80%1382 min20 min

This is a simplified model. Real charge sessions vary by battery chemistry, cell temperature, vehicle SoC limits and station power-sharing. Use as a planning estimate, not a guarantee.

How the model works

The session is split into 5%-SoC segments. For each segment the effective power is computed from the rated charger kW, scaled by three factors:

  • Taper. Below 80% SoC the rated power applies. Between 80% and 100% the curve linearly tapers down to about 30% of rated, reflecting how DCFC charging sessions slow sharply as the pack approaches full.
  • Temperature. Above 15°C ambient there is no penalty. Between 0 and 15°C a small linear penalty is applied. Below 0°C the model floors at roughly 40–60% of rated, capturing cold-soaked battery throttling.
  • Efficiency. A fixed multiplier accounts for line / conversion losses (≈92% DCFC, ≈90% AC).

The result is the time required to push the battery from start SoC to target SoC at the resulting effective rate.

Typical inputs

  • Home Level 2: 7–11 kW. Most overnight use cases.
  • DCFC mainstream: 50–150 kW. Common at highway-corridor sites.
  • DCFC ultra: 250–350 kW. Capable of high real-world rates only on vehicles whose pack supports it, and only below about 60% SoC.

Real sessions vary by vehicle (each model has its own charge curve), station load (power-sharing across stalls), pack temperature management, and SoC behavior. Use this as a planning estimate.