OEM battery
Supplied directly from Apple’s production chain. Identical power, chemistry, and calibration to the factory cell. Includes full calibration.
iPhone Battery Replacement – What You Need to Know
Every iPhone battery is a consumable – it wears out over time and that’s completely normal.
That’s when you start thinking about a replacement. When done properly, this service can extend your phone’s life by years. The problem is that the market is flooded with batteries of varying quality, and most repair shops have no interest in explaining the difference to you.
This page is here so you know what to ask, what to expect, and how to tell a good repair from a bad one – before you leave your phone with someone.
When do you need a battery replacement?
After 500 full cycles, Apple officially considers the battery worn out – under normal use this happens after about 2 years.
iPhone batteries degrade with every charge cycle. But the numbers are only a guideline.
Here’s what you actually feel:
- The phone doesn’t last until the end of the day with normal use.
- Percentages drop quickly and unevenly – for example from 40% to 10% in minutes.
- The phone shuts down by itself even though it shows remaining charge.
- You notice the whole phone starts to run slower. And that’s really the case, because iOS deliberately slows the phone down to protect the worn battery from sudden shutdowns.
- Another sign is that the phone heats up more than usual during simple tasks.
The easiest way to check is via Settings – Battery – Battery Health.
Below 80% replacement is absolutely mandatory according to Apple’s guidelines.
Around 85% you already feel the difference in real‑world use.
If you’re above 85% and still have issues, the cause may be something else and it’s worth doing a diagnosis before replacing anything.
What they don’t tell you about batteries
When you’re looking for a place to replace your battery, you’ll see words like “original battery” or “high-quality battery” almost everywhere. Very few repair shops explain what that actually means – and that’s not by accident.
There are three main types of batteries on the market:
Apple Service Pack
Official Apple spare part, manufactured by authorized service partners. Reliable performance with guaranteed compatibility.
Low quality
Unverified low‑quality cells with inconsistent characteristics. High risk of rapid wear, overheating, errors, and battery swelling.
Original battery (Service Pack) – manufactured by Apple and officially distributed. The phone fully recognizes it, reports 100% Battery Health with no messages or warnings. This is the most expensive option.
OEM battery – manufactured by the same factories that make original parts for Apple, but sold outside official channels. With a good manufacturer, the quality is comparable to the original at a lower price. The key phrase here is “with a good manufacturer” – OEM is not a standard, but a category with a huge range of quality.
Third‑tier batteries – cheap cells of unknown origin, sold under all sorts of names. They might last a month, they might last six – there’s no way to know in advance. These are exactly what most repair shops install when they say “original” or “high‑quality” without specifying. That’s because they’re the most profitable – one such cell can cost on average $2 to $5. Now compare how “cheap” the “cheap” repair really is, given we’re talking about a battery that costs less than a gas‑station coffee.
Beyond the cell itself, there’s another detail almost nobody mentions – calibration. On iPhone 12 and newer models, the battery must be programmed to the phone after replacement. Without this step you’ll see a “Unable to verify this battery” message in Settings, and Battery Health will not be reported correctly. This is not a defect in the battery – it’s a missed technical step on the part of the repair shop.
What should you pay attention to when choosing a repair shop?
Now that you know what the options on the market are, here’s an easy way to filter repair shops before you leave your phone for service:
There’s a reason for the low price
Be careful with prices that are too low. Battery replacement has a real cost – parts, labor, warranty. If the price is significantly below market, something is being cut somewhere along the line – most often the battery itself.
Ask informed questions
Ask directly what battery they install. Don’t ask “is it original” – that’s a pointless question because everyone will say yes. Ask “Is it Service Pack or OEM, and from which manufacturer?”. If they can’t give you a specific answer, you already have the answer you need.
Claim your warranty rights
Check the warranty. Not just whether they offer one, but what it actually covers. A warranty on labor is different from a warranty on the part. A good repair shop covers both.
Understand the quality of the service
Ask if they perform calibration after the replacement. For iPhone 12 and newer, this is a mandatory step. If the repair shop doesn’t know what you’re talking about or says it’s not necessary – avoid it.
See if the repair shop is a good fit
Check whether the repair shop is specialized. A store that fixes everything – phones, laptops, washing machines, car navigation systems, etc. – is rarely truly good at any of them. Specialization matters when we’re talking about precision electronics with tolerances down to fractions of a millimeter.
How we replace batteries at Zeero
Here’s what the process looks like with us, step by step:
We get the phone
We take in the phone and do a brief diagnosis before starting – we check the current Battery Health, whether there are any other issues, and confirm with you which battery option you want. No surprises afterwards.
Preparation for service
We place the phone in our first specialized machine, which gently heats it up to prepare the adhesive of the waterproof seal that holds the display in place for separation. This is a step many repair shops skip to save time – and it’s exactly why so many screens get broken during repair, but that’s a topic for another conversation.
Opening and cleaning
We open the phone with our second specialized machine, then place it on a dedicated stand that holds the screen in a fixed position while we remove the protective metal plates covering the connectors. Once those are removed, we disconnect the display and put it in a safe place, then take out the old battery and clean the base before installing the new one. This again is a step that is very often skipped or bypassed because someone wants to save time, but at Zeero we insist on proper installation.
Seal replacement
There’s one more step that often gets skipped – removing the old seal under the screen. In 90% of repairs done outside an official service center, this seal is not replaced and the phone is simply closed back up, which increases the risk of moisture, dust and liquid ingress because of a poorly adhered section. At Zeero we never allow this – before we even install the new battery, the old seal is removed and a new one is put in its place.
Installing the new battery
Only now, after everything has been properly prepared, do we install the new battery. We still don’t connect it to the motherboard, because first we put the display back in place and connect its connectors – the battery is always the first thing to be disconnected and the last thing to be connected.
Sealing the phone
Once everything is connected, we plug it in as well, then reinstall the protective plates exactly as they were placed at the factory. All that’s left is to prepare the seal by removing its protective film and snapping the screen back on, after which the phone goes into our special machine number 3, which heats and presses it so that the new seal sits evenly everywhere and adheres perfectly.
New battery calibration
As soon as this is done, we can calibrate the battery by programming it to the phone. From this point on, this battery is recorded as part of this device and does not belong to any other.
100% Battery Health
The result is 100% Battery Health in Settings, with no messages and no warnings. This is because Apple’s central server is also notified about the replacement, after which it gives its “OK” to the phone and the part is recognized.
Final tests
Once everything is done, we perform a final check – charging, Battery Health, temperature under load, operation of all components. Every iPhone goes through a 150+ point inspection after repair to make sure it’s returned in perfect condition.
Written 6‑month warranty
In the final step we hand back your phone with a written warranty where everything is clearly described, and we explain exactly what has been installed. Everything is done properly and to standard.
What to expect after the battery replacement?
Right after the repair, Battery Health will show 100%. The phone will recognize the battery as an original part – with no messages, warnings or errors in the settings.
During the first few days it’s normal for the battery to behave a bit unpredictably – the percentages may not be perfectly accurate, and actual screen‑on time may vary. This is not a problem with the repair. iOS needs a few full charge cycles to accurately calibrate the readings. After 3–4 cycles everything stabilizes.
To get the most out of your new battery, avoid keeping it constantly at 100% or letting it drop to 0%. The ideal range for long‑term health is between 20% and 80%. This isn’t a strict rule, but if you want the battery to wear out more slowly, it matters.
If after the repair you notice anything unusual – the phone heats up more than normal, Battery Health drops quickly, or some message appears – come back to us. The warranty covers exactly these cases and it’s not just a vague promise – you have it written down and stamped on paper.
Other frequently asked questions:
We’ve made sure to answer absolutely everything.
We work with all iPhone models – from iPhone 6 to the latest iPhone 17 series, including the Pro and Pro Max variants.
This also includes less common models like the iPhone SE (all generations), the iPhone mini series, and all Plus variants.
If you have an older model and aren’t sure whether we service it, the easiest way is to call us or check directly in our catalog – all available models with up‑to‑date prices are listed there.
The original battery (Service Pack) is manufactured directly for Apple and officially distributed. The phone fully recognizes it, reports 100% Battery Health with no messages or warnings, and Apple’s central server confirms the replacement. This is the most expensive option.
The OEM battery is manufactured by the same factories that supply components to Apple, but sold outside official channels. With a good manufacturer, the quality is comparable to the original but at a lower price.
The key point is “with a good manufacturer” – OEM is not a single standard, but a broad category with a huge range of quality. At Zeero we work only with vetted OEM suppliers with proven consistent quality. All OEM batteries are automatically calibrated and also show 100% Battery Health after replacement.
Yes, but in a positive way. iOS has a built‑in feature that deliberately slows the phone down when the battery is heavily worn – the goal is to protect it from sudden shutdowns during peak loads.
This means that if your phone feels slower than before, the reason may be the battery itself, not the phone.
After replacing the battery with a new, calibrated one, this limitation is automatically removed and the phone returns to its normal performance. Replacing the battery on an older model can make it feel like new again.
Yes, we work with Econt for the whole country. You send the phone to us, we perform the repair and send it back the same way.
For standard repairs like battery replacement, in most cases the phone arrives, the repair is done the very same day and it’s shipped back before the end of business hours.
Before sending your iPhone, it’s best to contact us so we can clarify all details in advance.
The price depends on two factors – the phone model and the type of battery you choose.
Newer models like the iPhone 15 and 16 series require more expensive parts, while older models are significantly more affordable.
As for battery type – the OEM option is more budget-friendly, while the original Apple Service Pack battery is more expensive but carries the Apple logo and your phone leaves with the same battery it had from the factory.
Specific prices for each model are published directly in our catalog – no hidden fees, everything is included in the price. What you see is the final price.
We take full responsibility. If any damage occurs during the repair that did not exist when we received the phone and performed the initial tests, we will fix it at our expense – with no extra charge for you.
That’s why when we accept any phone, we carry out a detailed inspection and document its condition, together with an automated process of 150+ tests before we even start working.
This gives peace of mind both to you and to us that we have a clear reference point for any potential discussion.
In practice, damage during repair is extremely rare when the right equipment and correct process are used – but if it happens, you know that we take responsibility.
Battery replacement takes about 30–60 minutes for a standard repair. You’re absolutely welcome to wait on-site, but we’re actually located in one of the most central areas of Sofia, at 80 Rakovski St.
Within walking distance you’ll find countless cafés, restaurants, shops, galleries, and parks.
You can grab a coffee on a nearby side street, stroll through the City Garden, run an errand, or just take a walk around the center.
If you prefer to drop off the phone and come back later at a convenient time, that’s also completely fine – we’ll let you know when it’s ready and we’ll wait as long as needed.
It’s easy to check on the spot before you leave. Open Settings – Battery – Battery Health. You should see 100% Maximum Capacity with no messages or warnings underneath.
If the phone is an iPhone 12 or newer, there should be no “Unable to verify this battery” message – if there is, calibration hasn’t been done and just needs to be completed, which takes a few minutes.
Also check whether the phone charges normally and whether it heats up unusually during use. At Zeero we perform this check before handing the phone back to you, so everything should already be fine – but it’s good to know what to look for.
Yes, in addition to the mandatory receipt, we also issue an invoice upon request.
If you need one, just tell the consultant when you hand in the phone or when you pay – we’ll prepare it on the spot. If you forget to ask while you’re here, contact us afterwards and we’ll issue it.
No – we specialize in Apple and Samsung devices.
For iPhone and Samsung phones we cover a full range of repairs – battery, display, glass, camera, ports and more. Besides phones, we also work with iPad, MacBook and Apple Watch.
If you have a device outside these categories, we still might be able to help – but call us and we’ll confirm. We believe it’s better to be everything for some, than something for everyone.