Battery health and cost summary
Degradation and ownership costs
Wear contributors and lifetime values
Range, mileage, and replacement impact
Savings, lost storage, and payback impact
Capacity and scenario projections
Steps, assumptions, and report
Core battery degradation formulas
Capacity loss = Original capacity − Current capacity
State of health = Current capacity ÷ Original capacity × 100
Degradation cost = Net replacement cost × Degradation percentage ÷ 100
Cycle wear per year = Annual equivalent cycles ÷ Expected cycle life × 100 × Stress factors
Remaining years = (Current health − Replacement threshold) ÷ Effective annual degradation rate
Levelised degradation cost = Net battery cost ÷ Expected lifetime delivered energy
Calculate battery degradation cost accurately
- Select the battery application, chemistry, currency, and degradation method.
- Enter original capacity, current capacity, state of health, and battery age.
- Add cycle count, depth of discharge, charging rates, and daily throughput.
- Describe operating temperatures, cooling, climate, humidity, and installation conditions.
- Enter purchase, replacement, maintenance, downtime, recycling, and salvage values.
- Complete the EV or solar inputs when those application modes are selected.
- Choose scenario factors, then calculate and review the forecast, charts, and report.
Sample NMC electric vehicle battery
| Input | Example value | Purpose |
|---|---|---|
| Original capacity | 75 kWh | Defines new-battery usable energy. |
| Current capacity | 68.25 kWh | Measures present capacity loss. |
| Battery age | 3.5 years | Supports calendar ageing estimates. |
| Completed cycles | 780 | Measures cycling consumption. |
| Average depth of discharge | 65% | Adjusts effective cycle stress. |
| Replacement cost | £8,200 | Values current degradation financially. |
Typical chemistry characteristics
| Chemistry | Typical cycle life | Typical efficiency | Common use |
|---|---|---|---|
| LiFePO₄ | 3,000–6,000 cycles | 92–97% | Solar storage and long-life systems |
| NMC | 1,500–3,000 cycles | 90–95% | Electric vehicles and portable systems |
| NCA | 1,200–2,500 cycles | 90–95% | High-energy electric vehicles |
| AGM | 400–1,000 cycles | 80–88% | UPS, backup, and marine use |
| Flooded lead-acid | 300–800 cycles | 75–85% | Low-cost backup and industrial use |
Actual values vary with design, temperature, charge limits, warranty definitions, and manufacturer testing.
Interpreting the result
| State of health | General interpretation | Suggested action |
|---|---|---|
| 90–100% | Low observed degradation | Continue normal monitoring. |
| 80–89% | Moderate capacity reduction | Review usage and thermal stress. |
| 70–79% | Material performance loss | Plan replacement or second-life use. |
| Below 70% | High degradation | Arrange inspection and replacement planning. |
Assumptions and safety notice
This calculator provides an engineering and financial estimate. It cannot inspect cell imbalance, internal resistance, swelling, thermal damage, or battery-management-system faults.
Manufacturer test methods and usable-capacity definitions differ. Always confirm warranty limits, service procedures, and replacement decisions with qualified technicians.
Do not open, puncture, bypass, or independently repair high-voltage batteries. Follow the manufacturer’s isolation, transport, recycling, and fire-safety requirements.
Battery degradation cost questions
What is battery degradation cost?
It is the financial value assigned to lost battery capacity, reduced performance, consumed cycle life, and future replacement obligations.
Should I use measured capacity or entered state of health?
Measured capacity is usually stronger when obtained through a reliable test. Entered state of health remains useful when the management system provides a trusted figure.
Why does depth of discharge affect cycle life?
Deeper cycles generally create more electrochemical and thermal stress. Shallow cycling often increases the number of usable cycles.
How does fast charging change degradation?
High charging power can increase heat and lithium plating risk. The effect depends on temperature control, chemistry, and charging limits.
What replacement threshold should I use?
Many applications use 70% to 80% state of health. Critical systems may need a higher threshold for reliability.
Does this calculator include calendar ageing?
Yes. The combined method estimates calendar ageing from time, temperature, storage state of charge, climate, cooling, and installation conditions.
Can I estimate electric vehicle range loss?
Yes. Select the electric vehicle application and enter original range, current range, annual mileage, energy consumption, and vehicle value.
Can I estimate solar-storage savings loss?
Yes. Solar mode estimates lost storage value, reduced annual savings, payback adjustment, and levelised stored-energy cost.
Why might actual degradation differ?
Cell design, software limits, charging behaviour, climate, maintenance, measurement error, and manufacturing variation can change real outcomes.