What is a second-life battery?

A second-life battery is an electric vehicle battery pack that has degraded below automotive performance thresholds—typically retaining 70–80 % of original capacity—but remains suitable for stationary energy-storage applications such as grid balancing, solar pairing, or backup power systems.

How is state of health calculated?

State of health (SoH) is computed as (current usable capacity ÷ original capacity) × 100. A pack that started at 64 kWh and now offers 45 kWh has a state of health of approximately 70.3 %.

Where does the value-per-kWh figure come from?

The value per kilowatt-hour is a user input reflecting prevailing market rates for second-life battery packs in the region of interest. Actual prices vary with cell chemistry, pack design, ease of disassembly, and local demand for energy-storage projects; buyers often quote £40–£100 per usable kWh depending on these factors.

Does this tool include collection or testing costs?

No. The calculator multiplies capacity by unit value to produce a gross resale estimate. Transportation, diagnostic testing, cell sorting, and regulatory certification fees are not deducted; net proceeds will be lower than the figure shown.

Can I use this calculator for lithium-ion, LFP, and NMC packs?

Yes. The formula applies to any battery chemistry because it uses usable capacity as the sole measure of value. However, market buyers may pay different rates per kWh for LFP (lithium iron phosphate) versus NMC (nickel manganese cobalt) packs due to cycle-life and safety characteristics; users should adjust the per-kWh input accordingly.

EV vs ICE

Second-Life Battery Resale Value

Estimate the resale value of a used EV battery pack based on remaining usable capacity.

Last updated: 25 June 2026

What this tool does

This calculator estimates the second-life resale value of a used electric vehicle battery pack using a simple capacity-based valuation model. The user enters the battery's original capacity (kWh), current usable capacity (kWh), and the prevailing market value per usable kWh; the tool multiplies current capacity by the per-kWh rate to produce an estimated resale value in pounds sterling. The calculator also computes state of health as a percentage of original capacity.

Inputs

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Battery Degradation Cost

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

Formula

V = C_{current} \times P_{kWh}

V

Estimated second-life resale value

C_{current}

Current usable capacity in kWh

P_{kWh}

Market value per usable kWh

How Second-Life Battery Resale Value works

Electric vehicle batteries that no longer meet automotive performance standards often retain 70–80 % of their original capacity and can be repurposed for stationary energy storage, grid balancing, or off-grid applications. This calculator estimates the resale value of a used EV battery pack by multiplying its current usable capacity by a market rate per kilowatt-hour. The result represents the potential proceeds from selling the pack to a second-life aggregator or installer.

The formula

Resale value = Current usable capacity (kWh) × Value per usable kWh (£/kWh)

The tool also computes State of Health (%) = (Current capacity ÷ Original capacity) × 100 to indicate how much of the pack's original energy storage remains available.

Where this method is most accurate

The calculation assumes a linear relationship between usable capacity and market value, which holds when battery packs are sold by nominal energy rating to integrators who will test and sort cells. Actual second-life prices vary with cell chemistry (NMC, LFP, NCA), pack form-factor, ease of disassembly, and regional demand for energy-storage systems. The model does not account for transportation costs, testing fees, or regulatory certification required in some markets.

What this tool does not do

The calculator does not fetch live market prices for second-life battery packs, predict future lithium or cobalt commodity trends, or assess the physical condition of individual modules. It does not determine whether a specific battery is eligible for warranty buyback programmes offered by some manufacturers. The output is a capacity-times-rate estimate only; actual offers depend on buyer due diligence and local supply-demand dynamics.

Disclaimer

This tool is provided for educational and informational purposes. It produces a mathematical estimate based on user-supplied inputs and does not constitute financial advice, vehicle-safety certification, or a guarantee of resale proceeds. Battery pack handling and repurposing may be subject to safety regulations and manufacturer intellectual-property restrictions in some jurisdictions.

Questions

What is a second-life battery?: A second-life battery is an electric vehicle battery pack that has degraded below automotive performance thresholds—typically retaining 70–80 % of original capacity—but remains suitable for stationary energy-storage applications such as grid balancing, solar pairing, or backup power systems.
How is state of health calculated?: State of health (SoH) is computed as (current usable capacity ÷ original capacity) × 100. A pack that started at 64 kWh and now offers 45 kWh has a state of health of approximately 70.3 %.
Where does the value-per-kWh figure come from?: The value per kilowatt-hour is a user input reflecting prevailing market rates for second-life battery packs in the region of interest. Actual prices vary with cell chemistry, pack design, ease of disassembly, and local demand for energy-storage projects; buyers often quote £40–£100 per usable kWh depending on these factors.
Does this tool include collection or testing costs?: No. The calculator multiplies capacity by unit value to produce a gross resale estimate. Transportation, diagnostic testing, cell sorting, and regulatory certification fees are not deducted; net proceeds will be lower than the figure shown.
Can I use this calculator for lithium-ion, LFP, and NMC packs?: Yes. The formula applies to any battery chemistry because it uses usable capacity as the sole measure of value. However, market buyers may pay different rates per kWh for LFP (lithium iron phosphate) versus NMC (nickel manganese cobalt) packs due to cycle-life and safety characteristics; users should adjust the per-kWh input accordingly.

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Sources & Methodology

The calculator multiplies current usable capacity (kWh) by the user-entered value per kWh (£/kWh) to estimate second-life resale value. State of health is computed as (current capacity ÷ original capacity) × 100. This linear capacity-based valuation model is commonly used by battery aggregators and energy-storage integrators when quoting prices for retired EV packs.

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