How to Get a Battery Health Certificate for a Used EV

A battery health certificate is a formal document confirming the state of health (SoH) of an electric car’s battery, issued by a trained technician using manufacturer-approved or specialist diagnostic equipment. In 2026 it is the most useful single document you can obtain before buying a used EV.

As of 2026, there is no UK law requiring a battery health certificate for private sales. However, many franchised dealers, approved used schemes and specialist EV retailers now include them as standard, and their absence from a listing should prompt questions.

What does a battery health certificate tell you?

A properly issued certificate should state:

• The vehicle’s battery state of health as a percentage at the time of testing
• The date and mileage at which the test was performed
• The testing method and equipment used
• The technician’s name and the issuing organisation
• In some cases: the number of charge cycles completed, charging session history (split between AC and DC) and any fault codes present in the battery management system

Some certificates also include an indication of the projected SoH trajectory and remaining warranty position.

Who issues battery health certificates?

Manufacturer-approved schemes

Several brands include battery health certificates as part of their approved used programmes:

• Volvo Selekt Used: Battery health report included as standard
• Polestar Certified Pre-Owned: Full battery diagnostic report
• Hyundai Approved Used: Battery check included; certificates available on request
• Kia Approved Used: Battery inspection standard on qualifying vehicles
• Renault Approved Used (for Zoe): Battery health report included

Buying through an approved used scheme gives you the best combination of peace of mind and documentation. The checks are conducted using the manufacturer’s own diagnostic tools, which access data that generic OBD2 equipment cannot always reach.

Independent specialist inspectors

Several independent organisations offer battery health inspections and certificates:

• The AA: Pre-purchase EV inspections include a battery health element. Prices from around £150 for a full inspection report
• The RAC: Similar pre-purchase inspection service, typically £99 to £150
• EV specialist workshops: Numerous independent EV specialists across the UK offer battery health certificates. Typical cost is £60 to £100 for a written certificate. Some combine this with a full vehicle health check
• Dealer-commissioned reports: A reputable dealer may have the battery independently tested and provide the report as part of the sale

What about OBD2 self-checks?

A buyer can perform their own battery health check using an OBD2 Bluetooth dongle (£15 to £40) and an appropriate app. Tools such as LeafSpy (for Nissan Leaf), Car Scanner, EVBatMon or Torque Pro can display battery SoH, cell voltages and other data for many models.

This is a legitimate and useful check, particularly if you are comfortable with the technology. However, it does not produce a formal certificate and is less useful than a professional report for negotiating purposes or for your own records. It is also not available for Teslas, which do not expose battery data through a standard OBD2 port.

How much does a battery health certificate cost?

Source	Approximate cost	What you get
Manufacturer approved used scheme	Included in purchase	Certificate, limited warranty
AA pre-purchase inspection	£99 to £175	Full written inspection including battery
RAC pre-purchase inspection	£99 to £150	Full written inspection including battery
Independent EV specialist	£60 to £100	Battery health certificate only
OBD2 self-check	£15 to £40 (dongle)	Data reading, no formal certificate

When is a battery health certificate essential?

You should insist on a battery health certificate (or have one commissioned) in the following situations:

1. Buying privately. You have no consumer rights protection equivalent to a dealer purchase. A degraded battery with no disclosure would leave you with a significantly less valuable car and no recourse.
2. Buying an older or high-mileage car. Any EV over five years old or with more than 60,000 miles should be checked regardless of how good it looks.
3. Buying an air-cooled model. Nissan Leaf (pre-2019) and early Renault Zoe batteries are more susceptible to degradation than liquid-cooled alternatives. Insist on a check.
4. Buying a premium EV. A Jaguar I-Pace or Audi e-tron with a compromised battery could mean a replacement bill of £10,000 or more. The £100 cost of a certificate is trivial by comparison.
5. Any purchase without a manufacturer warranty. If there is no remaining warranty, you bear the full cost of a replacement battery. You need to know what you are taking on.

How to use a battery health certificate in negotiations

A certificate showing 78% SoH on a car listed at full market rate is a negotiating lever. Use the table below as a starting point:

SoH result	Suggested price adjustment
95% or above	Pay asking price or close to it
90% to 95%	Marginal discount; car is in excellent condition
85% to 90%	Request 3% to 7% reduction
80% to 85%	Request 8% to 12% reduction
75% to 80%	Request 12% to 18% reduction; consider carefully
Below 75%	Walk away, or price in battery replacement cost

Most reputable sellers and dealers will respond positively to evidence-based negotiation. If a seller refuses to allow an independent inspection or dismisses battery health as irrelevant, treat that as a warning sign.

Does a battery health certificate include any warranty?

Not automatically. A certificate confirms current condition but does not guarantee future performance. However, some approved used schemes tie a limited battery warranty to the certificate. For example, some dealers offer a six to twelve month warranty against the battery dropping below a stated SoH threshold following the certificate date.

Read the terms carefully. A certificate that says “battery is currently at 87% SoH” is different from one that says “battery is warranted to remain above 80% for the next 12 months.”

What the certificate cannot tell you

A battery health certificate measures current capacity. It cannot precisely predict future degradation rate, because that depends on how the car is used and charged going forward. A car with 89% SoH that is then exclusively rapid-charged to 100% daily may degrade faster than one with 86% SoH that is carefully home-charged to 80%.

Use the certificate alongside information about charging history, previous keeper information and the model’s known degradation track record to build a complete picture.

Where to next?

For the full used EV buying process, return to the used EVs guide. To see which models have the best battery longevity records, visit our best used electric cars page.