How to check your Hyundai Ioniq 5's battery health
The Ioniq 5 is on the opposite end of the scale from the cars that made battery degradation a talking point. The E-GMP pack is liquid-cooled and actively managed, the 800V architecture means less current and so less heat for a given charging speed, and the car will precondition the pack on the way to a rapid charger. Packs on these cars generally age slowly and predictably, and the spread between two similar cars is much narrower than on an air-cooled EV.
None of which tells you where yours actually sits. There is no state-of-health figure anywhere in the car's menus, and Bluelink does not report one either. The battery management system knows precisely, and will tell you over the diagnostic port, but nothing in the car surfaces it.
There is one wrinkle specific to these cars, and it catches people out: the reported SOH holds at exactly 100.0% for a long time, often years, and then steps down rather than gliding. A 100% reading on a car with real miles on it is normal, not a sign of a suspiciously healthy pack, and the per-cell deterioration figures are the ones that move first. This page covers how to read both.
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 Hyundai 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 Hyundai Ioniq 5 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: Take the reading with the pack settled: not straight after a rapid charge and not after a long motorway run. Expect 100.0% for the first few years. That is the BMS being conservative about when it commits to a lower number, not the pack being untouched.
Cell deterioration figures
Same hardware5 minutesFine-grained
Same hardware, same session, finer resolution. The route worth using while SOH is still pinned at 100%.
- With Car Scanner connected as above, find “Battery Max Cell Deterioration” and “Battery Min Cell Deterioration”, usually just below SOH on the EV dashboard.
- Record both. The max figure is the worst cell in the pack and is the one that matters most; the min figure is the best cell.
- Note the gap between them. A pack whose cells are deteriorating together is behaving normally; a widening spread is the pattern worth watching.
Worth knowing: These are the BMS's own per-cell estimates, not a lab measurement, and like SOH they are recalculated over time rather than being continuously live. A single reading is a data point; the trend across several is the useful thing.
A Hyundai dealer battery health check
PaidNeeds a bookingDocumented
Costs money and a booking, but produces a printed figure, which is what a warranty claim and a private buyer both want to see.
- Book an EV or battery health check with a Hyundai 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. If you are anywhere near the warranty threshold, a dated figure from a franchised dealer is the document that matters.
Worth knowing: The underlying number is the same one Car Scanner reads off the same BMS. You are paying for the printout and for the fact that a buyer or a warranty assessor did not have to take your word for it.
What the numbers mean
- SOH
- State of health as a percentage of the pack's original capacity, and the headline figure to enter on a check. On these cars it holds at 100.0% for a long time and then steps, so read it as a coarse but trustworthy floor rather than a live measurement.
- Max / min cell deterioration
- Per-cell capacity loss against new, for the worst and best cell in the pack. These move earlier than SOH does, which makes them the more informative pair on a young car. Enter the max figure, and the min if you have it.
- Cell voltage deviation
- The spread between the highest and lowest cell voltage, in millivolts. A few tens of millivolts on a pack at rest is ordinary. A persistently large deviation, especially at low state of charge, points at balance rather than capacity.
- Cumulative charge / discharge energy
- Lifetime kWh in and out of the pack. It is a far better proxy for how hard the car has worked than the odometer, and it is the figure to ask about on a used car whose history is thin.
- BMS SoC vs dash SoC
- The BMS reports a raw state of charge on a wider scale than the dashboard, because the pack keeps a buffer at each end. Seeing 95% on the BMS when the dash says 100% is the buffer, not a fault.
Why your SoH reads exactly 100%
The E-GMP battery management system does not report a continuously refined capacity estimate the way some rivals do. It holds 100.0% until it has enough confidence to commit to a lower figure, then steps down, often by a whole percent at once. Owners regularly see 100% at 40,000 or 50,000 miles. Two consequences follow. First, do not read 100% as proof of an untouched pack, and check the cell deterioration figures alongside it, because those move first. Second, a suspiciously fresh 100% on a high-mileage car can also follow a BMS software update, which can reset the estimate. Ask when the car was last updated before you read anything into it.
Why these packs age slowly
Liquid cooling means the pack's temperature is managed rather than inherited from the weather, which removes the single biggest driver of calendar ageing on air-cooled EVs. The 800V architecture halves the current needed for a given charging power, so the headline rapid-charge speeds generate less heat than the numbers suggest, and later cars precondition the pack when you navigate to a rapid charger. Habitual rapid charging matters much less here than it does on a Leaf. What still matters is sitting at 100% for long periods in warm weather; if you are not about to set off on a long run, the charge limit is the setting worth using.
Which pack you have
UK cars launched in 2021 with a 58 kWh standard-range pack or a 77.4 kWh long-range pack (72.6 kWh usable), both NMC. The 2025 facelift moved to larger 63 kWh and 84 kWh packs, and the Ioniq 5 N is a different animal again with its own thermal calibration and a much harder life. Compare like with like: a long-range car and a standard-range car of the same age are not the same comparison, and the check will treat them separately.
Warranty, and the thing that is not the battery
Hyundai covers the high-voltage battery in the UK for 8 years or 100,000 miles, against capacity falling below roughly 70%. Terms vary by market and by when the car was registered, so check the handbook for your car rather than trusting a forum. Separately, and worth knowing when buying used: the ICCU, which manages 12V charging and vehicle-to-load, has been the subject of recall work on these cars. It is not the traction battery and it does not affect your SOH figure, but it is the fault owners actually encounter, and you want the recall work confirmed as done.
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 Hyundai Ioniq 5s 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 Hyundai Ioniq 5Common questions
What is a normal state of health for an Ioniq 5?
For the first few years, 100%, because that is what the BMS reports whether or not the pack has lost anything. Beyond that these cars typically hold up well. Rather than quote a number, run a check: the report compares your figure against other Ioniq 5s of similar age and mileage, and tells you how large the sample was.
Does Bluelink show battery health?
No. Bluelink covers charging, climate and location, but not state of health. There is no route to a figure that does not involve either the diagnostic port or a dealer.
My car has 60,000 miles and still reads 100%. Is that real?
It is a real reading, but not the whole picture. Check the max cell deterioration figure at the same time. If SOH is 100% and deterioration is a couple of percent, the pack is fine and the BMS simply has not stepped yet. If the car has recently had a software update, the estimate may also have been reset.
Will frequent 350 kW rapid charging damage the pack?
Much less than owners expect. The pack is designed around that charging curve, it is liquid-cooled throughout, and the 800V system keeps currents lower than the power figures imply. Time spent parked at a high state of charge in warm weather is the habit worth changing first.
Is the procedure the same on a Kia EV6 or a Genesis GV60?
Yes. They share the E-GMP platform and the same battery management system, so the adapter, the app and the figures are identical. Only the vehicle profile you pick in Car Scanner changes, along with the warranty terms.
Will plugging in an OBD adapter harm my car?
Reading data over OBD-II is passive and is what the port is for. Unplug the adapter when you are not using it: some cheap adapters draw current continuously, and a flat 12V battery is a nuisance you do not want to invite on a car where the 12V system already gets attention.