How do I build a simple energy budget for a long EV trip?

Break the route into legs between workable charging options. For a hypothetical 180 km leg at 20 kWh/100 km, the driving-energy estimate is 36 kWh. Use route distance rather than straight-line distance and include meaningful charging detours.

Calculate the energy available between starting charge and the chosen arrival reserve. If a 60 kWh battery starts at 85% and the reserve is 15%, the illustrative available energy is 42 kWh. That leaves only 6 kWh above the 36 kWh estimate.

At 24 kWh/100 km, that leg would need 43.2 kWh and exceed the illustrative 42 kWh budget. The solution is to revise the charging plan or starting assumptions, not to hide the difference with optimistic rounding.

Verify compatible charging, access hours and payment options for every essential stop. A list of stations does not prove each one is working or available on arrival. Include an alternative that remains reachable before the reserve becomes the only remaining energy.

During the journey, compare actual consumption and predicted arrival charge with the plan. Make changes while options remain available. The arithmetic helps make uncertainty visible; it cannot replace vehicle warnings, current road conditions or safe driving decisions.