Peace of mind for your used EVIndependent EV battery health & range checks

Mazda electric vehicle driving on a coastal road

EV Battery Check · £9.99

EV Battery Health Check

Check a used electric car's battery health before you buy: estimated range retention, real-world range now vs when new, and how much battery warranty is left. Battery data powered by ClearWatt.

Estimated battery health & range retention vs when new
Battery health grade where a manufacturer test record exists
Expected real-world range now vs the official WLTP figure
Remaining battery warranty in miles & months
Usable & total battery capacity (kWh)
Full refund if we can't generate your report

Start your check

EV Battery Check

The battery can be up to 40% of the car’s value

What an EV battery health check tells you

On a petrol car, you check the mileage and the service history. On an electric car, the number that really decides value is one you can’t see: the health of the battery. It’s the most expensive part to replace, and there’s no legal requirement for a seller to show you its condition.

Our battery check estimates that condition before you commit: how much range the car should still hold, how that compares with when it was new, and how much battery warranty is left. It needs only a reg and the current mileage, so you can run it straight from a listing.

Battery-health grade (where a test record exists)
Estimated range retention vs when new
Expected real-world range now
Official WLTP range, side by side with real
Remaining battery warranty (miles & months)
Usable & total battery capacity (kWh)

Sample readingPowered by ClearWatt

Estimated battery health

A+

0%50%100%

Estimated range now: 203-220 mi
Range when new (WLTP): 292 mi
Battery warranty left: 65,000 mi · 59 mo

See a full sample report

What you get for £9.99

What the battery check shows

The battery and range reading is the paid core of every report. The same £9.99 check also includes charging, running cost, efficiency and spec where we hold that data. See the full Used EV Check.

Your battery readingIncluded

Battery health & range

Battery-health grade

Where a record exists

A letter grade such as A+, shown where a manufacturer battery test record exists for the car.

Estimated range retention

How much of the car’s original range it’s likely to still hold, as a percentage, from aggregated real-world test data.

Expected range now vs when new

The miles this specific car should realistically do today, and how far below its when-new range that is.

Range performance (WLTP vs real)

The official WLTP figure the car was sold on, set against the estimated real-world range now.

Remaining battery warranty

How many miles and months of manufacturer battery cover are left, with an Active / Expired badge.

Battery capacity

Usable and total capacity in kWh, and the WLTP range the car was rated for when new.

The mileage that informs it

Provided by the DVSA

MOT mileage history

A mileage timeline from official MOT readings, which is both an independent cross-check and a direct input into the range estimate above.

Powered by ClearWatt. Estimated range is based upon aggregated test data and actual vehicle performance may vary. For more information please consult ClearWatt’s Terms and Conditions. MOT and mileage history is provided by the DVSA.

Battery health, explained

Understand the numbers before you buy

What is battery State of Health, and how do we estimate it?

State of Health (SoH) describes how much of a battery’s original capacity remains. A brand-new pack is at 100%; as it ages and is used, that figure slowly falls. A true SoH reading needs a physical test with the car plugged in, which you can’t do from a listing before you view.

So we do the next best thing. Using aggregated real-world data from thousands of electric cars, plus the age and mileage of the exact car you’re checking, we estimate how much range it’s likely to still hold versus when it was new. Where a manufacturer battery test record exists, we also show a health grade. It’s an estimate and a grade, framed honestly (not a measured SoH percentage), and it’s the reading no advert, V5C or MOT will give you.

What counts as normal degradation?

Some range loss is completely normal. Large-scale fleet studies put average degradation at around 1.8-2.3% of capacity a year. Call it roughly 2%, though it varies with chemistry, climate and how the car has been charged: a lot of DC rapid charging and regularly sitting at 100% both accelerate wear.

That’s why mileage alone is a poor guide. A well-treated 80,000-mile car can have a healthier battery than a hard-charged 30,000-mile one. Seeing the estimated retention against the car’s age tells you whether its wear is normal for the type, or a red flag worth walking away from.

Real-world range vs WLTP: the honest gap

WLTP is the official lab figure a car is sold on, and almost nobody achieves it in daily driving. Your check shows the estimated real-world range for this car today next to that WLTP number, so you can judge the true, everyday distance before you buy, not after.

Every range figure is an estimate from aggregated test data, and your own results will still shift with driving style, weather and terrain. We never quote a guaranteed range.

Why age and mileage drive battery health

A battery ages in two ways at once: calendar ageing over time, and cycle ageing from use. That’s why the check asks for the car’s current mileage: it turns a generic “this model when new” figure into an estimate for this specific car, at its real age and use, today.

We pre-fill the mileage from the latest MOT reading so you only have to confirm it, and the same MOT timeline doubles as an independent check that the odometer hasn’t been tampered with.

Reading the percentage

What’s a good battery health percentage for a used EV?

Battery health is usually talked about as a percentage of the capacity the pack had when new. The same yardstick works for the estimated range-retention figure in your report. Age matters as much as the number itself: 88% on a six-year-old car is healthy; the same figure on a two-year-old car deserves questions.

90% and above

Excellent

Better than typical for a car more than a couple of years old. Expect close-to-original range, and little to argue about on battery grounds.

85-90%

Good: normal wear

Where most healthy three-to-five-year-old EVs sit. Nothing alarming; just make sure the price reflects the modest range loss.

80-85%

Fair: check the price

More wear than average for a younger car. Fine at the right price. But ask about charging history, and negotiate with the numbers in hand.

Below 80%

Investigate

Unusual outside the oldest, hardest-worked cars. Negotiate hard or walk away, and note most manufacturer warranties only step in below around 70%.

Your report puts the car you’re checking on this scale: the battery bar shows its estimated retention against when it was new, so you can see at a glance whether the wear is normal for its age, and price the car accordingly.

Battery warranties

EV battery warranties, and what’s left on a used one

Manufacturers warranty the battery separately from the rest of the car, and usually for longer. Cover runs to two limits at once, a number of years and a mileage, and ends at whichever comes first. It guarantees the pack stays above a set capacity, commonly around 70%, rather than promising zero degradation, and it normally transfers to you when you buy the car.

So the question that matters on a used EV is not whether it had a warranty when new, but how much is left today. Terms vary by brand, here are the typical ones.

Brand	Typical battery cover	Worth knowing
Most makers	8 years / 100,000 miles, to ~70% capacity	VW, BMW, Vauxhall, Peugeot and others; cover transfers with the car
Kia	7 years / 100,000 miles	Whole-car warranty with the battery included, transferable (8 years on some 2024-on cars)
Hyundai	8 years / 100,000 miles, to 70%	Reduced to 5 years where the car was a taxi or private-hire vehicle
MG	7 years / 80,000 miles, rising to 8 years / 100,000 from 2024	Depends on the registration date; lower again for private hire
Tesla	8 years / 100,000–120,000 miles, to 70%	Mileage cap varies by model and RWD vs Long Range / Performance
Nissan Leaf	8 years / 100,000 miles	Written in dashboard bars: covered if capacity drops below 9 of 12
Renault Zoe	8 years / 100,000 miles, to ~66-70%	Only where the battery is owned — many early cars had a battery lease
Toyota bZ4X	8 years / 100,000 miles, to 70%	Extendable up to 10 years with annual battery health checks

Typical terms, condensed for guidance, they vary by model year, trim and how the car was used. Always confirm the exact cover for a specific car.

Your report turns this into the number that matters: it shows the remaining battery warranty for the specific car, in both miles and months, with a clear Active or Expired badge, so you know whether the most expensive part of the car is still protected before you buy. For the full picture, see our guide to how EV battery warranties work.

Choose the right tool

Ways to check an EV’s battery health, compared

There are three honest ways to judge a used EV’s battery, and they answer the question at different moments. The right strategy is usually a combination.

Garage or dealer diagnostic test

Measured, read from the car itself

A plugged-in diagnostic gives the most precise reading, a measured State of Health. The catch: it needs the car at the garage, so it only works once you already have access to the vehicle.

Typically £35-£110+ · needs the car

App-based driving test

Accurate, but needs the owner and time

Apps that analyse real driving can build a strong picture of the pack, but they typically need around a week of data, so they depend on the current owner running the test on your behalf.

Around £40 · takes about a week

Instant reg-based estimate (this check)

The pre-purchase screen

From just the reg and mileage, we estimate range retention using aggregated real-world data plus the exact car’s age and use. It takes seconds, straight from the listing, before you ever contact the seller.

£9.99 · instant, from the advert

They’re complements, not rivals. Use the instant check to screen listings from your sofa and rule out the cars with tired batteries, then save a physical, plugged-in test for the one car you’re serious enough about to visit.

Honest by design

An estimate you can trust, framed honestly

We’d rather be straight with you than over-promise. The battery reading is an estimate built from aggregated real-world data and the car’s own age and mileage, with a health grade shown only where a manufacturer test record exists. It is not a measured State of Health.

“Estimated range is based upon aggregated test data and actual vehicle performance may vary. For more information please consult ClearWatt’s Terms and Conditions.”

MOT and mileage history is provided by the DVSA. And if we can’t produce your battery and range report, you’re refunded in full, automatically.

FAQs

EV battery health questions

Can you really tell a used EV’s battery health from the reg?

We can give you a well-founded estimate. From the registration and the current mileage, we estimate how much of the car’s original range it’s likely to still hold, and show a battery-health grade where a manufacturer test record exists. It isn’t a physical, plugged-in test, but it’s the read you can get before you view the car.

Is this a measured State of Health (SoH)?

No. We show an estimated range-retention figure and a health grade where a test record exists, not an OBD-measured SoH percentage. A measured SoH requires diagnostic access to the car itself.

What’s a normal amount of battery degradation?

Around 2% of capacity a year is typical (large fleet studies measure averages between 1.8% and 2.3%), though it depends on the car’s chemistry, climate and charging history. The report shows the estimated retention against the car’s age so you can judge whether its wear is normal.

What if there’s no battery test record for the car?

You still get the estimated range-retention figure, expected range now versus when new, and remaining warranty. The letter grade is only shown where a manufacturer test record exists for that specific car.

How is this different from the Used EV Check?

It’s the same £9.99 report. This page just leads with the battery-health story. The full Used EV Check page covers the whole report, including charging, running cost, efficiency and spec, where we hold that data.

What if you can’t produce my report?

If the battery and range data isn’t available for your car, we don’t produce a report and you’re refunded in full, automatically.

What’s a good battery health percentage for a used EV?

As a rule of thumb: 90% and above is excellent for a car more than a couple of years old, mid-80s to low-90s is normal at three to five years, and anything below 80% deserves investigation or a lower price. Most manufacturer warranties only step in below around 70%.

How much does it cost to replace an EV battery?

Typically £5,000-£15,000+ depending on the model; around £8,000 is a common estimate for a full pack. That’s exactly why the battery’s condition matters more than any other single check on a used EV.

How long do EV batteries last?

Longer than most people expect. At typical degradation rates of around 2% a year, recent large-scale fleet studies suggest packs can last 20 years or more, often outlasting the car itself. Individual cars still vary with how they’ve been charged, which is what the check is for.

Does rapid charging damage an EV battery?

Heavy, frequent DC rapid charging accelerates wear: fleet data suggests predominantly rapid-charged batteries can degrade at roughly twice the rate of gently charged ones. Occasional rapid charging is fine; it’s the everyday habit that leaves a mark, and it’s why two identical cars can hold very different batteries.

How is this different from a garage battery test?

A garage test plugs into the car and measures its State of Health. It’s the most precise reading, but it typically costs £35-£110+ and needs the car in front of you. Ours is an instant estimate from the reg and mileage, built to screen cars before you view. Many buyers use both: this check to shortlist, a plugged-in test to confirm the final car.

How much does an EV battery health check cost?

Ours is £9.99 flat, with a full automatic refund if we can’t produce your report. A plugged-in garage test typically runs £35-£110+, and app-based driving tests around £40. Those produce a measured or driven reading, but both need access to the car first.

EV model guides

Know the model? Start with its guide

Typical battery, real-world range, warranty terms and the used-buyer watch-outs for the UK's most popular used EVs, then check the specific car by registration.

Nissan Leaf