Battery BN-45 from Xiaomi: what phones are suitable and how not to make a mistake with the choice

If you’re looking for information about Xiaomi’s BN-45 battery, you’re probably wondering about one of two things: whether you want to replace the battery in your smartphone or whether the battery you find will fit your model. This article is one of the most common Xiaomi battery articles, but its compatibility depends on the specific phone modification and year of release.

In this article, we will take a closer look at which Xiaomi phones are designed for the BN-45 battery, how to distinguish the original part from the fake, and what to do if your smartphone does not support this battery, and you will find a compatibility table, check instructions and answers to frequent questions – all to avoid mistakes when buying.

Important: Even if your phone is on the list of compatible models, the BN-45 battery may have different revisions (e.g., BN-45A, BN-45B) that are not always interchangeable.

What is BN-45 and how to decipher it?

The BN-45 is the internal battery designation in Xiaomi's system, which stands for:

• 🔋 BN — Abbreviation for Battery Number, the standard prefix for Xiaomi batteries.
• 📏 45 is the symbol for a container or series, in this case it is 4500 mAh (the actual capacity may vary slightly).

However, not all batteries with this label are the same, for example, there are options:

• 🔄 BN-45A — The first revision, often found in the Redmi Note 8 Pro.
• 🔄 BN-45B — Modification with improved protection system, installed in the Redmi Note 9 Pro.
• 🔄 BN-45M — option for models with support for fast charging 33W.

If only BN-45 is listed on the battery without the letter suffix, it could be both a generic version and a fake. Xiaomi's original batteries always have full letter markings.

List of Xiaomi phones compatible with BN-45

The BN-45 battery (and its modifications) was installed in several Xiaomi smartphone lines, and here is a full list of models for which this battery is officially suitable (with due regard to revisions):

Please note:

• ⚠️ Redmi Note 9 Pro for the Chinese market (Redmi Note 9 Pro) 5G) battery BN-46, inconsistent BN-45.
• ⚠️ POCO X3 NFC battery BN-50 (5160 mAh – it cannot be replaced by BN-45.

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Check the labeling on the old battery before buying – even if the phone model matches, the revision (letter after the BN-45) may be different.

How to Check if BN-45 is Right for Your Phone

If your model is not in the table above or you are not sure of compatibility, follow the following steps:

1. Remove the back cover (if possible without damage) and look at the markings on the original battery. It should match the BN-45X (where X is the letter of revision).
2. Check capacity: If the battery is specified 5020 mAh, and you buy a BN-45A for 4500 mAh, these are incompatible options.
3. Use the service codes: ##4636##In the Battery Information menu, check the battery model.

If you buy a battery separately, be sure to check with the seller:

• 📋 Accurate marking (with the letter).
• 🔌 Compatible with your phone model (sometimes sellers provide incomplete data).
• 🔒 Protection against overheating and charge control (it is often not available in fakes).

How dangerous is the installation of an incompatible battery BN-45

If you made the wrong choice and installed a BN-45 battery in your phone that is not designed for your model, the consequences can be serious:

⚠️ Warning: A battery with the wrong capacity or voltage can cause the board to overheat, the power controller to wear out quickly, or even catch fire when charging.

Specific risks:

• 🔥 Overheating: if the battery is designed for a different charging current (for example, 18W instead 33W).
• 📉 Rapid degradation: incompatible battery loses capacity 2-3 times faster.
• ⚡ Charging problems: phone may show 100% but suddenly shut down.
• 🚫 Charging lock: modern Xiaomi smartphones detect non-original batteries and refuse to charge.

Example: the user installed a BN-45A (4500 mAh) in the Redmi Note 9 Pro, where the BN-45B (5020 mAh) should be, the result is that the phone only charged up to 85% and turned off at 30% of the remainder.

How to Buy an Original BN-45 Battery and How to Avoid Counterfeiting

The original BN-45 batteries are sold as follows:

• 🛒 Official Xiaomi stores (Mi Store, authorized resellers).

Signs of forgery:

• 🔍 There is no hologram or sticker with QR-code (in the original there is a code).
• 📦 Packaging is not sealed or has typos in the labeling.
• ⚖️ The battery weight is much smaller (the original weight is less). ~100-110 g).
• 🔋 The sticker is easy to move away - on the original it is glued firmly.

Average price of the original BN-45 battery (2026):

• BN-45M: 1800–2200 ₽ (fast-charging).

⚠️ AliExpress often sells "improved" versions BN-45 With a capacity of 6000 mAh or 7000 mAh. This is a fraud - the real capacity of such batteries rarely exceeds 4000 mAh, and the risk of fire increases 3-4 times.

How to replace the battery BN-45: Step-by-step instructions

If you are considering replacing the battery with your own hands, follow this instruction.

• 🔧 Plastic mediator or guitar mediator (to remove the cover).
• 🔥 Hair dryer or thermo-air station (for softening glue).
• ⚡ New battery BN-45 (compatible).
• 🧲 Magnetic screwdriver (for screws) T3 or T4).

Procedure:

1. Turn off the phone and remove it. SIM-map.
2. Heat the hair dryer around the perimeter (temperature ~60 ° C) for 2-3 minutes.
3. Carefully tuck the cover with the mediator, starting at the bottom edge (where the charging connector is).
4. Unscrew the screws that fix the metal plate of the battery.
5. Disconnect the battery plume from the motherboard (use plastic tweezers!).
6. Remove the old battery and install a new one by plugging in the plume.
7. Collect the phone in reverse order, making sure all plumes are tightly connected.

After replacement:

• 🔋 Fully discharge and charge your phone 2-3 times to calibrate the controller.
• 📊 Check the container with ##4636## (must match the marking).

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If the phone doesn’t turn on after replacing, check the battery plume connection – this is the most common mistake when replacing yourself.

BN-45: What batteries can be used instead?

If the original BN-45 can't be found, then alternatives can be considered, but remember that any replacement with a non-original battery reduces the reliability of the phone.

Permissible options:

Warnings:

• ⚠️ Batteries from other brands (such as Samsung or Huawei) are prohibited – different protection schemes!
• ⚠️ AliExpress batteries without Xiaomi labels often have an understated real capacity.

FAQ: Frequent questions about the BN-45 battery