How to check your Kia EV6's battery health

Most EV6s reaching the used market now are four-year-old cars with the original 77.4 kWh pack, and they are the reason this figure is worth having. The E-GMP pack is liquid-cooled and actively managed, so it degrades slowly and consistently, which cuts both ways: the pack in a good car is probably fine, and the pack in a badly treated one will not look obviously different from the outside.

Kia gives you no way to find out from the driver's seat. There is no state-of-health readout in the menus and none in the Kia Connect app. The battery management system holds the figure and reports it over the diagnostic port, which costs about £15 of hardware and a quarter of an hour to reach.

Two things about these cars shape how you read the answer. The reported SOH sits at exactly 100.0% for years before stepping down, so the per-cell deterioration figures are the ones with resolution early in a car's life. And Kia's battery warranty runs to 7 years, not 8, which changes the arithmetic on a used car more than most buyers realise.

How to get the figure

Car Scanner + an OBD-II adapter

~£15 + app unlock15 minutesDefinitive

The definitive answer. Reads the battery management system's own state-of-health figure, the same number a Kia dealer's kit reports.

Buy a Bluetooth OBD-II adapter. E-GMP cars work with most reasonable BLE adapters, though the very cheapest ELM327 clones still drop connections.
Install Car Scanner ELM OBD2 (Android or iOS). The battery figures sit behind the app's one-off paid unlock, so budget a few pounds on top of the adapter.
Find the OBD-II port under the dashboard on the driver's side, near the bonnet release. It sits behind a small trim cover on some trims.
Switch the car fully on, to READY rather than accessory, then pair the adapter and select the Kia EV6 profile in Car Scanner. The profile matters: a generic OBD-II profile will not expose the battery management system's figures at all.
Open the EV dashboard and read “Battery State of Health (SOH)”. Record the max and min cell deterioration percentages next to it at the same time.

Worth knowing: Read it with the pack settled rather than hot from a rapid charge or a long run. On a car under about three years old, expect 100.0%: the BMS is slow to commit to a lower figure, and that is normal rather than remarkable.

Cell deterioration figures

Same hardware5 minutesFine-grained

Same hardware, same session, finer resolution. The figures that actually move while SOH is still reading 100%.

With Car Scanner connected as above, find “Battery Max Cell Deterioration” and “Battery Min Cell Deterioration” on the EV dashboard.
Record both. The max figure describes the worst cell in the pack, which is what sets the pack's usable capacity, so it is the number to lead with.
Compare the two. Cells deteriorating in step is the healthy pattern; a gap that grows between readings is what deserves a closer look.

Worth knowing: These are BMS estimates rather than measurements, and they are recalculated periodically rather than live. Judge them on the trend across several readings, not on one.

A Kia dealer battery health check

PaidNeeds a bookingDocumented

Costs money and a booking, but the printed figure is what a warranty claim needs and what a private buyer will pay for.

Book an EV or battery health check with a Kia dealer or an EV-specialist independent.
Ask for the state-of-health figure and the printout, not just a pass or fail.
Keep the report, particularly if the car is in its sixth or seventh year, where a dated figure inside the warranty term is worth having on file.

Worth knowing: It is the same BMS figure that Car Scanner reads. What you are buying is the document and the third-party name on it.

What the numbers mean

SOH: State of health as a percentage of original capacity, and the figure to enter on a check. It holds at 100.0% for a long time and then steps down, so treat it as a reliable floor rather than a precise current value.
Max / min cell deterioration: Per-cell capacity loss against new, for the worst and the best cell. These carry real resolution on a car whose SOH still reads 100%, which is most EV6s under three years old. Enter the max figure, and the min alongside it if you have it.
Cell voltage deviation: The gap between the highest and lowest cell voltage, in millivolts. Tens of millivolts on a resting pack is ordinary; a large, persistent deviation is a balance question rather than a capacity one.
Cumulative charge / discharge energy: Lifetime kWh through the pack. On a used EV6 with a vague history, this tells you far more about how the car has been used than the mileage does, and a GT with modest miles can still show a lot of energy through the pack.
Battery inlet / module temperatures: What the cooling system is seeing. Useful mainly for context on a reading: figures taken with the pack still warm from a rapid charge are the ones most likely to look odd.

Which pack you have, and why it matters here

Cars built from 2021 to 2024 came with either a 58 kWh standard-range or a 77.4 kWh long-range pack (74 kWh usable). The 2025 facelift moved to larger 63 kWh and 84 kWh packs. The EV6 GT sits apart from both: same platform and cooling, but a pack asked for far more power far more often, and its degradation should be read against other GTs rather than against a long-range RWD car. Age and pack generation have to be matched before a comparison means anything, which is what the check does for you.

The 7-year warranty and used-car arithmetic

Kia's high-voltage battery warranty in the UK runs to 7 years or 100,000 miles, covering capacity falling below roughly 70%. That is a year shorter than several rivals, and it lands squarely on the cars now selling used: a 2021 car is out of battery cover in 2028. Terms vary by market and registration date, so confirm against the car's own handbook and service record. If you are buying, the remaining term is worth as much as the SOH figure, and a documented dealer reading taken while cover is still live is the thing to ask the seller for.

Why these packs hold up

Liquid cooling keeps the pack out of the temperature extremes that drive calendar ageing, and the 800V architecture means a 200 kW charge draws roughly half the current an equivalent 400V car would, so the fast charging these cars are known for is less punishing than the headline numbers imply. Later software added pack preconditioning when you navigate to a rapid charger. The habit that still costs capacity is leaving the car sitting at 100% in warm weather, which is what the charge limit setting is for.

The fault owners actually meet

The ICCU, which handles 12V charging and vehicle-to-load, has been the subject of recall and software work across E-GMP cars including the EV6. It has nothing to do with the traction pack and will not move your SOH figure, but it is the failure these cars are known for. On a used car, confirm the outstanding recall work has been carried out before you spend time on the battery reading.

Now find out whether your figure is normal

A state-of-health percentage on its own does not tell you much. What matters is how it compares with other Kia EV6s of the same age and similar mileage. Tirion’s report tells you exactly that, along with the size of the sample behind the comparison, so you can judge how much weight the answer deserves. It is free and takes about two minutes.

Check my Kia EV6

Common questions

What is a normal state of health for a Kia EV6?

Under about three years old, 100%, because that is what the BMS reports regardless. Beyond that the honest answer depends on pack generation, mileage and whether it is a GT. Run a check and the report compares your figure against other EV6s of similar age and mileage, and tells you the size of the sample behind the comparison.

Does the Kia Connect app show battery health?

No. Kia Connect handles charging, climate and location. State of health is not exposed anywhere in the app or the car's own menus, so the diagnostic port or a dealer are the only routes.

Is the EV6 GT worth checking differently?

Same procedure, different expectations. The pack sees far higher sustained power, so read the cumulative discharge energy alongside SOH, and compare against other GTs rather than against a long-range RWD car of the same age.

Is this the same as checking a Hyundai Ioniq 5?

Yes. The EV6 and the Ioniq 5 share the E-GMP platform and the same battery management system, so the hardware, the app and the readouts are identical. You pick a different vehicle profile in Car Scanner, and the warranty terms differ: Kia's battery cover runs 7 years, Hyundai's 8.

My SoH dropped a whole percent between readings. Is that a problem?

No, that is how this BMS reports. It holds a figure until it is confident enough to move, then steps rather than glides, so a one-percent drop between two readings is the estimate updating, not the pack losing a percent that week. Judge it across months.

Will plugging in an OBD adapter harm my car?

Reading over OBD-II is passive and is exactly what the port exists for. Unplug the adapter when you are done, because some cheap adapters keep drawing current and will flatten the 12V battery over a few weeks.