Battery health not showing after a battery replacement, or a warning that iOS cannot verify the battery, means your iPhone cannot confirm the new cell is a genuine, calibrated Apple battery. The phone still works. What you lose is a trustworthy health reading, and on some repairs the battery may not perform as it should. Here is how to read the message and what to check.
The short answer
- Open Settings, then General, then About, then Parts and Service History, and read the word next to Battery: Genuine, Used, Finish Repair or Unknown.
- If it says Finish Repair, update iOS, join Wi-Fi, charge above 20 per cent and tap Restart & Finish Repair.
- If it says Unknown, treat the Battery Health percentage as unreliable and judge the battery by how long it lasts and whether it shuts down early.
- Ask the repairer in writing what battery was fitted. The message alone does not prove the cell is poor quality.
- If the battery swells or the back of the phone lifts, stop charging, switch the phone off and bring it in. Do not open it.
Why battery health is not showing: the verification check
Battery Health lives under Settings, then Battery. It reports two things: Maximum Capacity, which compares the battery with when it was new, and Peak Performance Capability, which tells you whether the battery can still deliver the bursts of power the processor asks for[1]. Both figures come from data the battery reports to iOS. A genuine Apple battery is designed to work with iOS so that charge level and health are reported properly[2].
When iOS cannot verify the battery, iPhone XS, XS Max, XR and later show this message in Battery Health: “Unable to verify this iPhone has a genuine Apple battery.” Apple adds that details from the battery may not be accurate[1]. On iPhone X and earlier the wording is “Important Battery Message”, with a note that the phone is unable to determine battery health[1].
So whether the percentage is missing, frozen at 100 per cent or sitting beside the warning, the advice is the same. Do not trust the number until the battery is verified.
What Parts and Service History says about the battery
The battery is one of the parts iOS reports on in Parts and Service History, on iPhone XR, iPhone XS models, iPhone SE (2nd and 3rd generation) and every model since[3]. You find it under Settings, General, About. If an Unknown part is detected, the phone shows a notification the first time you open it after the repair and again five days later[3]. On iOS 15.1 or earlier you see an Important Battery Message instead of the Unknown label[2].
| Label next to Battery | What it means | What to do |
|---|---|---|
| Genuine | The repair used genuine Apple parts and processes | Nothing. Battery Health should read normally. |
| Used | A genuine Apple battery previously fitted to another iPhone (iPhone 15 and later on iOS 18) | Acceptable if you were told. Apple notes it may not perform as well as a new genuine battery. |
| Finish Repair | A new Apple battery has been fitted but the repair has not been completed in Repair Assistant | Run Repair Assistant (steps below). |
| Unknown | Not genuine, not working as expected, not verified after the repair, or modified | Find out what was fitted and test the battery yourself. |
The Used, Finish Repair and Unknown definitions come from Apple’s genuine battery guidance[2].
Finishing the repair with Repair Assistant
A genuine battery that shows Finish Repair has not been calibrated to your phone yet. Repair Assistant handles batteries on iPhone 12 and later and on iPhone SE (3rd generation)[4]. Work through it in this order:
- Update iOS. Apple requires the latest version before Repair Assistant will run[4].
- Join an ordinary Wi-Fi network. Hotel and café networks with a sign-in page will not work, nor will networks that use 802.1X authentication.
- Charge above 20 per cent. Repair Assistant will not start below that[4].
- Run it. Settings, General, About, Parts & Service History, then Restart & Finish Repair[4].
- If it refuses, go back to the repairer. A part installed by someone else may be protected by Activation Lock, and then only the point of service can finish the repair[4].
You can keep using the phone with the repair unfinished, but Apple says the part may not perform as well as a calibrated one[4]. Finish it.
Battery health not showing after battery replacement? Test the battery instead
An Unknown battery can still be a good battery. With no reliable percentage, judge it the way our technicians do on the bench: by behaviour, not by the number in Settings.
- Charge to full and note the time. Then use the phone normally for a day. A fresh battery should comfortably outlast the old one on the same routine. If it does not, something is wrong with the cell or with what is draining it. Our guide to why a phone battery drains fast covers the software causes worth ruling out first.
- Watch the low end. Unexpected shutdowns at 20 or 30 per cent point to a weak cell or poor calibration. On many models, iOS responds to an unexpected shutdown by applying performance management to prevent another[1], which you would see as a slower phone.
- Check the fit. Lay the phone flat on a table. If it rocks, or the screen edge has lifted, stop charging and see the safety section below.
- Feel for heat while charging. Warm is normal. Too hot to hold is not.
- Re-check after the next iOS update. Apple warns that non-genuine batteries can behave unexpectedly after installation, after updates and while charging[2].
What a non-genuine battery can get wrong
Apple lists the ways a non-genuine or unverified battery can fall short: poor design or manufacturing, a cell that has been used before, a damaged cell, or the wrong battery for the model. Any of these can mean low capacity, a poor fit or unexpected behaviour[2]. Apple also states that non-genuine batteries may lead to safety issues, and that an Unknown battery might affect the trade-in value of the phone[2].
The engineering behind that list is simple. A phone battery is only as good as the cell inside it and the small circuit board that manages charging and reports capacity. A well-made replacement gets both right. A cheap one can carry less capacity than the label claims, or report figures iOS cannot verify. That is why we judge a replacement on run time and stability rather than on its packaging.
Battery figures worth knowing
Apple designs the batteries in iPhone 14 models and earlier to keep 80 per cent of their original capacity at 500 complete charge cycles under ideal conditions, and those in iPhone 15 models and later to keep 80 per cent at 1,000 cycles[1][5]. On iPhone 15 and later with iOS 17.4 or later, Battery Health also shows the cycle count, manufacture date and first-use date[5]. After a replacement on those models, a cycle count near zero and a recent manufacture date are good signs that the cell is new. Read them before you leave the shop.
Swollen or overheating batteries: stop first
If the battery has swollen, the London Fire Brigade’s advice is to stop charging immediately, switch the device off and not open the casing. Contact the manufacturer or a certified technician instead[6]. The Brigade also advises buying replacement batteries and chargers only as branded, genuine products from a supplier you trust[6].
Do not press the screen back down and do not keep charging a phone whose back or screen has lifted. A damaged lithium-ion battery is a fire risk, and prising a phone open at home is the easiest way to damage one further. Bring it in switched off.
DIY or bench repair?
| Symptom after a battery replacement | Try first | Bring it to a technician when |
|---|---|---|
| Finish Repair label | Run Repair Assistant | It fails or the part is locked to another account |
| Unknown label, phone lasts all day | Nothing urgent. Keep the repair receipt | Run time falls off within weeks |
| Shuts down at 20 to 30 per cent | Charge to full once and use it down to empty | It keeps happening |
| Phone rocks on a table or screen lifts | Stop charging and switch off | Straight away |
| Very hot while charging | Use the original cable and adapter | It stays hot with a known good charger |
Your rights if the battery is not what you were told
A battery replacement is a service, so the Consumer Rights Act 2015 requires the repairer to carry out the work with reasonable care and skill[7]. If you were told a genuine Apple battery was fitted and Parts and Service History says Unknown, ask the repairer to finish the repair first, since an unverified genuine battery shows the same label. If they then confirm a different battery was used, put your complaint in writing.
For a wider look at when a new battery is worth it, see our guide to phone battery replacement in the UK. If you are buying a used iPhone, check Parts and Service History before you hand over any money, and our buy and sell phones counter can look a phone over with you.
When to bring it to us
- Battery Health missing or showing the verification warning, and the phone dies early: we test the battery under load to separate a weak cell from a software or charging-circuit drain before suggesting a replacement.
- Finish Repair that will not complete: we go through the network, charge and iOS requirements with you and check what was fitted.
- Swelling, a lifted screen or heat while charging: switch the phone off and bring it in. We open swollen phones on the bench so the cell is never punctured at home.
- Unexpected shutdowns after a replacement elsewhere: we check the battery connector and the fit, which are the parts most often disturbed.
Every device gets a free diagnostic, and if we cannot fix it there is no fee. Battery replacement starts from £29 on our mobile phone repair services page, with the final price confirmed after the diagnostic. Walk in seven days a week at our Bloomsbury shop at 67 Marchmont Street, WC1N 1AP (Monday to Saturday 9:30 am to 9:00 pm, Sunday 10:00 am to 8:00 pm) or our Moorgate shop at 16 City Road, EC1Y 2AA (Monday to Saturday 9:00 am to 9:00 pm, Sunday 10:00 am to 8:00 pm).
Frequently asked questions
Why does my iPhone say it cannot verify a genuine Apple battery?
iOS could not confirm the new battery is a genuine Apple part that has been verified for your phone. It can mean a non-Apple battery, a faulty one, or a genuine battery whose repair has not been finished. The phone still works, but the health details may not be accurate.
Will battery health come back after a replacement?
Yes, with a genuine Apple battery and a completed Repair Assistant calibration. With a non-genuine battery, expect the warning to stay and judge the battery by run time instead.
Can the battery message be removed?
Only by fitting a genuine Apple battery and finishing the repair so iOS can verify it. Anything sold as a way to hide the warning leaves the battery itself unchanged.
Is an Unknown battery dangerous?
Not automatically. Apple says non-genuine batteries may lead to safety issues, so watch for swelling, heat and early shutdowns, and stop charging at once if the phone starts to bulge.
If your new battery is showing a warning and something does not feel right, book a free diagnostic or find your nearest InstaTech shop.
Sources and references
- iPhone battery and performance, Apple Support (UK). Accessed 8 October 2026. ↩
- About genuine iPhone batteries, Apple Support (UK). Accessed 8 October 2026. ↩
- iPhone Parts and Service History, Apple Support (UK). Accessed 8 October 2026. ↩
- Use Repair Assistant to finish an iPhone or iPad repair, Apple Support (UK). Accessed 8 October 2026. ↩
- About the battery and performance of iPhone 11 and later, Apple Support (UK). Accessed 8 October 2026. ↩
- Batteries and chargers – Fire safety at home, London Fire Brigade. Accessed 8 October 2026. ↩
- Consumer Rights Act 2015, section 49: Service to be performed with reasonable care and skill, legislation.gov.uk (The National Archives). Accessed 8 October 2026. ↩
