Listings mostly link the BN4A battery model name to the Redmi Note 7 and its Pro sibling. Spare listings give the pack as 4000 mAh typical capacity at about 3.8 V. BN starts the Xiaomi family of codes, which covers Redmi and POCO phones, but the letters alone never tell you the exact phone.
Both phones are older models now, so the original pack in many of them has seen hundreds of charge cycles. That is why people search for this code: the phone dies early, or the back has started to lift, and a replacement is needed. Before you order anything, read the code on the cell itself. The Redmi Note 7S looks like a cousin, but no reliable source confirms its pack, so read its own label before buying.
Quick facts
Step by step
Note the exact phone and its model number
Open Settings, then About phone. If the model number is hidden, type model in the Settings search bar. Note whether the name says Note 7 or Note 7 Pro.
Have the technician read the cell sticker
After the back is lifted, the sticker shows
BN4Aalong with capacity and voltage. Ask for a clear photo of it before the pack is touched.Compare the new pack with the old one
Put both packs side by side. The code, the size and the connector end must be the same. A pack that is a little shorter or longer is the wrong one.
Check weight and print
A real pack feels about as heavy as the old one and has sharp print with batch details. A light pack that claims a very high mAh is a fake.
Phones that take the BN4A battery model name
BN4A parts listings agree on the Note 7 and Note 7 Pro. The two launched together with similar bodies and 4000 mAh class cells, which suits a shared BN4A. The table shows how firm each BN4A match is.
| Redmi Note handset | Status | Note |
|---|---|---|
| Redmi Note 7 | Most BN4A listings name it | BN4A at 4000 mAh typical, about 3.8 V |
| Redmi Note 7 Pro | Matched by most listings | Check the old BN4A sticker to confirm |
| Redmi Note 7S | Not confirmed | Check the code on its own label |
| Redmi Note 8 | Not assumed to match | See its own page |
For the phone-first view, open the Redmi Note 7 battery page. If a list and your pack disagree, believe the pack.
Note 7, Note 7 Pro or Note 7S: sort out your version
Many owners only say "Note 7" at the counter, and that can mean three different boxes. The plain Note 7, the Note 7 Pro and the Note 7S were sold as separate versions with their own model numbers. About phone shows whether yours is the Note 7 or the Note 7 Pro. The retail box carries it too.
Since the same name can hide different hardware, never order on the phone name alone. Give the technician the model number, along with a photo of the cell sticker. If the sticker reads BN4A, the order is safe. If it shows another code, stop and look that code up instead.
A customer with a Note 7 Pro asked for a Note 7 battery from a shelf box. The pack had the right capacity on the front, but its code ended in a different letter and the connector sat a few millimetres away. Reading the old sticker first saved a second trip.
What the 4000 mAh figure means for this pack
Adverts and spare listings quote 4000 mAh as the typical capacity. BN4A labels often print a slightly lower rated figure. For BN4A, copy the rated value from your own label, because it may differ between batches and there is no official figure to quote here.
BN4A's watt hours: 4000 mAh times the voltage on its label, over 1000. Near 3.8 V, BN4A holds about 15.2 Wh. Even at 4000 mAh, a Note 7 Pro cell at another voltage stores different energy, so read both numbers.
A Note 7's day depends on its screen, reception, brightness and apps. A fresh 4000 mAh pack in an older phone like this one usually lasts a working day with moderate use, but an aged pack will give far less.
Codes people confuse with BN4A
Xiaomi codes look alike, and one changed letter can mean a different phone. The trouble usually comes from nearby Redmi phones of similar size, so check each code on its own page rather than guessing.
- BN46 and BN5A belong to other Redmi phones. Similar capacity is no reason to swap them in.
- The Redmi Note 8 follows in the series, but is not assumed to use BN4A.
- On a worn sticker, 4 and A can be misread, and so can N and M. Tilt the label under strong light before you trust a letter.
For every Xiaomi code family in one table, open the full Xiaomi and POCO code table.
Signs that a BN4A pack is wearing out
| Note 7 sign | Why it occurs | Next step for BN4A |
|---|---|---|
| Note 7 percentage drops in jumps | BN4A worn after many cycles | Test Note 7 health, then plan a BN4A |
| Note 7 Pro goes dark at 15 to 30 percent | Tired BN4A sags under sudden load | Ask a technician to test BN4A |
| Note 7 screen lifts or back gap widens | BN4A has swollen | Unplug the Note 7 and go today |
| Note 7 charges slowly and runs warm | Weak pack, damaged cable or heavy apps | Try another cable, then get it tested |
On the Note 7, rule out apps and signal with our drain guide, then use our health steps on BN4A.
Swelling, heat, leaks or dents turn BN4A into a fire hazard. Unplug the Note 7, leave the puffed cell alone and move it from warmth. Carry it to an authorised service centre. BN4A fakes often print far above 4000 mAh, so buy only an exact code match.
Fitting a new pack in a Note 7
The Note 7 and Note 7 Pro have sealed bodies with a glass back held down by adhesive. Opening one badly can crack the glass or tear the battery connector, so leave this job to an authorised service centre or a local technician you already trust. Give them the Note 7 model number and have BN4A compared with the old sticker.
Look over a new BN4A for these clues:
- It weighs less than the Note 7's old cell.
- The BN4A print is blurred and has no batch details.
- The label claims well over 4000 mAh from a cell this small, which no honest pack can give.
See our battery swap guide for fitting advice.
Ask the technician to run a charge and discharge test while you wait, and keep your picture of the old cell label.
Looking after an older Redmi Note 7 battery
After years of use, a pack reacts badly to heat and to sitting at 100 percent for long hours. When the Note 7 charges, keep it clear of pillows and parked cars, and peel off a thick case if it heats up.
Pair the Note 7 Pro with a charger and cable in good order, replacing any lead that warms. If the Note 7 still dies suddenly after a restart and full charge, BN4A is the likely cause. A fresh BN4A pack with the right code usually brings back a full day of use.
Frequently asked questions
Which phone uses the BN4A battery model name?
Most listings pair BN4A with the Note 7 and Note 7 Pro. Its typical capacity is 4000 mAh. The Note 7S is not confirmed, so read the sticker on its old cell.
Does the Redmi Note 7 Pro use BN4A?
Most sellers agree it does. Lift the back and BN4A is printed right on the cell.
How many mAh does BN4A hold?
Its typical capacity is 4000 mAh. The rated figure on your cell label can come out slightly under that, so go by your own label.
Can a BN46 replace BN4A?
Never assume that. Different codes may differ in size or plug, even at similar capacity. Match the full code on the old sticker.
Is the Redmi Note 7S battery also BN4A?
It is not confirmed here. Check the Note 7S cell label before ordering.
What gives away a fake BN4A?
Counterfeit BN4A packs weigh less, print blurrily, skip batch marks and claim more than 4000 mAh. Weigh and compare it with the old pack.