EV Battery Energy and Range

Automotive Engineering · CHAPTER 4 / 5

Level: introductory undergraduate · Study session: 15–20 minutes including practice.

Learning outcome: Estimate range using usable energy and consumption.

Before you begin: Complete earlier chapters in this discipline; revise algebra and units as needed.

1. Understand the idea

Range is usable battery energy divided by energy consumed per distance. Usable energy can be smaller than nameplate energy because of operating reserves and state of health. Consumption depends on route, speed, weather, auxiliary loads and driving style. Charging losses affect energy purchased rather than this battery-to-road calculation.

2. Write the model

Range (km) = usable energy (kWh) / consumption (kWh/km)

Define the symbols from the worked case before substituting values. Keep units consistent, record the assumptions and round only after the calculation.

3. Follow a worked example

A battery with 50 kWh usable energy and consumption of 0.15 kWh/km has an ideal estimated range of 333.3 km. At 0.20 kWh/km, it falls to 250 km.

4. Explore the model

Figure: calculated teaching cases; straight segments connect sampled points, not experimental observations. Read exact values below.

Illustrative scenario sweep — synthetic educational data
Consumption (kWh/100 km)	Usable energy (kWh)	Estimated range (km)
12	50	416.667
15	50	333.333
20	50	250

Hold usable energy fixed and sweep consumption. Explain why highway speed or air conditioning can reduce range.

5. Reproduce it yourself

Copy the input cases into Excel or a notebook and name each quantity and unit.
Recalculate each result from the stated equation or rule. For qualitative cases, explain the state or partition decision instead.
Change one input, predict the direction of change, then calculate again.
Write one sentence explaining where the model stops being valid.

6. Check your understanding

What range follows from 40 kWh at 0.16 kWh/km?

Reveal the answer and check your work

250 km.

Compare your result, units and reasoning. If they differ, return to the equation and test the worked case first.

7. Common mistake

This estimate is not a guaranteed real-world range.

Further study and academic note

Explore the discipline reference and further learning resources. This is an original IIMEEE introductory teaching note with synthetic examples; it is not a peer-reviewed research result or a professional design specification. Figures were constructed from the listed teaching cases. Resource links support further study and do not imply endorsement.