---
title: "Comparing battery characteristics"
subject: "Energy Environment and Society"
chapter: 5
key: "semester_7/energy_environment_and_society:battery-characteristics-comparison"
source: https://www.bctengineer.com/q/semester_7/energy_environment_and_society/battery-characteristics-comparison
site: BCT Engineering
---

# Comparing battery characteristics

Energy Environment and Society · Chapter 5: Energy Storage

- Asked in: year not given
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/energy_environment_and_society/battery-characteristics-comparison
- Whole chapter: https://www.bctengineer.com/md/semester_7/energy_environment_and_society/chapter-5

## Question

Compare the characteristics of various types of batteries.

## Short answer

Lead-acid is cheap and common but heavy. Li-ion offers the highest energy density (100–250 Wh/kg) and efficiency (90–95%) with long cycle life. Flow batteries provide the longest life (10,000+ cycles) for grid storage. Key metrics include voltage, density, cost, and safety.

## Answer

The common characteristics used to compare batteries are nominal cell voltage, energy density, power density, cycle life, efficiency, self-discharge, cost, safety and environmental impact. (Values are typical and vary by manufacturer.)

| Characteristic | Lead-acid | NiCd | NiMH | Li-ion | Flow (vanadium) |
|---|---|---|---|---|---|
| Cell voltage (V) | 2.0 | 1.2 | 1.2 | 3.2–3.7 | 1.2–1.4 |
| Energy density (Wh/kg) | 30–50 | 40–60 | 60–120 | 100–250 | 15–25 |
| Cycle life | 300–1000 | 1000–2000 | 500–1000 | 500–3000+ | 10,000+ |
| Round-trip efficiency | 70–85% | 70–80% | 65–80% | 90–95% | 65–80% |
| Self-discharge (per month) | 3–5% | 15–20% | 20–30% | 1–3% | Very low |
| Memory effect | No | Yes | Little | No | No |
| Cost | Lowest | Medium | Medium | Higher (falling) | High |
| Safety | Acid, hydrogen gas | Toxic cadmium | Good | Fire risk (thermal runaway) | Safe |
| Typical use | Vehicles, UPS, solar home systems | Tools, emergency lights | Hybrid cars, AA | EVs, phones, grid | Large grid storage |

Summary: lead-acid is cheap and common in Nepal for inverters and solar systems but heavy; Li-ion has the best energy density and life and is taking over; flow batteries are best for long-duration storage.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Which battery type has the highest energy density and round-trip efficiency in the comparison?
   A. Lead-acid
   B. NiCd
   C. Li-ion
   D. Vanadium flow
   Answer: C. Li-ion has 100-250 Wh/kg and 90-95% efficiency, the best of those listed. (Key point: Best energy density and efficiency)

2. Which battery has a clear memory effect and toxic cadmium?
   A. NiCd
   B. Lead-acid
   C. Li-ion
   D. Vanadium flow
   Answer: A. NiCd shows a memory effect, and its cadmium is toxic. (Key point: Memory effect)

3. Why are vanadium flow batteries suited to large, long-duration grid storage?
   A. Highest energy density of all
   B. Very long cycle life (10,000+), very low self-discharge and safe operation, though energy density is low
   C. Lowest cost
   D. Highest cell voltage
   Answer: B. They last over 10,000 cycles with very low self-discharge, but have only 15-25 Wh/kg and high cost. (Key point: Flow battery strength)

4. Why is lead-acid common in Nepal for inverters and solar systems?
   A. It has the best energy density
   B. It is the cheapest and widely available, though heavy with short cycle life
   C. It has no safety issues
   D. It has the longest cycle life
   Answer: B. It has the lowest cost, but energy density is only 30-50 Wh/kg and life is 300-1000 cycles. (Key point: Lead-acid in Nepal)

## Related in Energy Environment and Society

- [Battery hazards and prevention](https://www.bctengineer.com/question.md?key=semester_7%2Fenergy_environment_and_society%3Abattery-hazards-prevention) — Energy Environment and Society, chapter 4, asked 3×

## Related in other subjects

- [Battery fundamentals and battery bank sizing](https://www.bctengineer.com/question.md?key=semester_6%2Fenergy_resources%3Abattery-fundamentals-sizing) — Energy Resources, chapter 6
- [Comparing systems of traction electrification](https://www.bctengineer.com/question.md?key=semester_7%2Futilization_of_electrical_energy%3Atraction-electrification-systems-comparison) — Utilization of Electrical Energy, chapter 4
- [SLI and station batteries and charging methods](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Asli-station-battery-charging) — Industrial Power Distribution and Illumination, chapter 9
- [Relational operators comparing lengths](https://www.bctengineer.com/question.md?key=semester_3%2Fobject_oriented_programming%3Aoverload-relational-length) — Object Oriented Programming, chapter 5