EVWired

04 · Road trips

How many charging stops might a trip need?

Estimate the minimum number of charging stops implied by a trip's energy requirement and a chosen battery reserve. Use it before checking actual stations; it cannot tell you where to stop.

Your inputs

Get your result

Use your own figures or load the worked example below. All calculations stay in this browser.

kmTotal road distance, before any charger detours.
kWhUsable battery capacity for the vehicle.
%Battery percentage when leaving.
%Minimum charge retained at each modeled arrival.
%Maximum percentage charged to at each stop.
kWh / 100 kmUse a highway or trip-specific figure when available.
kWAverage session power, including taper; not advertised peak power.
Add a distance, vehicle, and preferred battery reserve.

This is an energy estimate, not a route or station finder. Terrain, weather, traffic, detours, and charging curves change the result.

How to use this tool

  1. Enter trip distance, usable battery capacity and expected trip consumption.
  2. Set your starting charge, arrival reserve and stop target. Starting charge must meet the reserve; the stop target must exceed it.
  3. Enter average charging power and calculate. Verify each proposed leg and a backup station in a route planner.

Worked example

A 500 km drive with a 10% reserve

Trip distance
500 km
Usable battery
75 kWh
Starting charge
90 %
Arrival reserve
10 %
Charge target at stops
80 %
Trip consumption
20 kWh / 100 km
Average charging power
90 kW

Expected result 1 charging stop · 40 kWh to add · about 0.5 charging hours

The drive needs 100 kWh. Leaving at 90% with a 10% reserve provides 60 kWh. The remaining 40 kWh fits within one 52.5 kWh stop window. Time is 40 ÷ 90 × 1.15 = 0.51 hours.

Transparent estimates

How to read this result

Stop count is an energy-based minimum with ideally located chargers. The last stop may be partial. The 15% time allowance is proportional; queues, detours and fixed connection time are excluded.

How it is calculated

  • Trip energy = distance × consumption ÷ 100.
  • Energy available before the first stop = battery capacity × (starting charge − reserve).
  • Stops are estimated by dividing the remaining energy by the usable energy between the reserve and stop target. Time = energy added ÷ average power × 1.15.

Assumptions

  • Each modeled stop begins at the reserve level and can charge up to the selected target; the last stop may be partial.
  • A proportional 15% time allowance is applied to energy divided by average power; fixed connection time is excluded.

What this estimate cannot tell you

  • The result does not select stations or account for road grade, wind, temperature, charger availability, or vehicle-specific charging taper.
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