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EV vs ICE

Battery Degradation Cost

Calculate the economic cost of battery capacity loss over your planned ownership period.

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What this tool does

This calculator applies compound degradation to estimate the monetary value of battery capacity lost during ownership. It requires four inputs—original capacity (kWh), annual percentage loss, battery replacement cost, and ownership duration—and returns the cost of degraded capacity as a fraction of replacement cost. The method assumes constant percentage loss per year; real-world degradation may vary with usage patterns and temperature.

Inputs
(kWh)
(%)
(£)
(yrs)
Result
Result

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Formula
Degradation cost (£)
Annual capacity loss rate (%)
Ownership period (years)
Battery replacement cost (£)

How Battery Degradation Cost works

This tool estimates the economic value of capacity lost as an electric-vehicle battery ages. It multiplies the fraction of capacity lost over time by the cost of a replacement battery pack. The output is a single currency figure representing the notional depreciation of the battery asset, useful for comparing total ownership costs or resale-value adjustments.

The formula

The calculator applies compound annual degradation:
Remaining fraction = (1 − annual_loss / 100)years
Lost fraction = 1 − remaining fraction
Degradation cost = lost fraction × replacement cost

For example, a 64 kWh pack losing 2.3% per year over 8 years retains 82.8% of its capacity; the 17.2% lost multiplied by a £9,000 replacement cost yields £1,529.

Where this method is most accurate

The compound-loss model fits EV batteries experiencing relatively steady calendar and cycle ageing. It works best when the annual loss rate reflects empirical data from the specific chemistry and usage profile. Accuracy depends on realistic inputs: aggressive fast-charging, extreme climates, or deep daily cycles can accelerate degradation beyond typical percentages cited by manufacturers.

What this tool does not do

The calculator does not predict degradation rate—users must supply the percentage from warranty documents, third-party studies, or fleet data. It does not account for non-linear ageing (early rapid loss followed by plateau), temperature effects, or warranty coverage that may replace the pack at no cost. It also ignores the possibility of cell-level refurbishment, which can restore capacity at lower cost than full replacement.

Disclaimer

This tool is for educational and comparison purposes only. It does not constitute vehicle purchasing advice, battery warranty interpretation, or financial guidance. Actual degradation and replacement costs vary by manufacturer, model year, usage, and geographic market. Always consult manufacturer specifications and warranty terms before making ownership decisions.

Questions

What does 'capacity loss per year' mean?
It is the percentage of total pack capacity the battery loses annually, compounded. A 2.3% loss means the pack retains 97.7% of the previous year's capacity each year, not 2.3 percentage points off the original.
Where can I find realistic degradation rates?
Manufacturer battery warranties often guarantee a minimum state-of-health after a set period (e.g. 70% after 8 years), from which an average annual rate can be back-calculated. Third-party studies of fleet data also publish typical rates for specific models.
Does this calculator account for warranty replacement?
No. It assumes the owner bears the full cost of lost capacity. If a warranty covers degradation below a threshold, the actual economic loss may be zero or reduced.
Why use replacement cost instead of original pack cost?
Replacement cost reflects the current or future market price of a battery, which tends to decline over time. Using today's replacement price gives a conservative estimate; using projected future prices (if available) may improve accuracy for long ownership periods.
Can I use this for hybrid batteries?
Yes, provided the inputs match the hybrid pack's capacity and known degradation profile. Hybrid batteries often degrade differently due to shallower cycling and different chemistries, so annual loss rates may differ from pure EVs.

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Sources & Methodology

Applies compound annual degradation: remaining_fraction = (1 − annual_loss/100)^years; cost = (1 − remaining_fraction) × replacement_cost. The method treats degradation as a geometric decay, common in lithium-ion aging models. Sources: battery warranty disclosures and academic aging studies.

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