The Mi A3 battery model is BM4F, and spare part listings give it as 4030 mAh typical. The phone is the Xiaomi Mi A3, with model numbers M1906F9SH and M1906F9SI in the same listings. The Redmi A3 is a different and newer phone. Its pack is not BM4F, and most listings give it the code BN5R at 5000 mAh typical.
This is why "redmi a3 battery model" and "mi a3 battery model" bring up the wrong results for each other. One word separates the two names, and the batteries are different in code, size and capacity. Read the name on the box or in Settings first, then match the code. Since BM4F is printed on the cell, the Mi A3 must be opened before the code can be read.
Quick facts
Step by step
Read the full phone name
Look at the retail box or open Settings and then About phone. Note whether the name starts with Mi or Redmi. If the model number is hidden, type model in the Settings search bar.
Match the model number to the pack
The Mi A3 model numbers in listings begin with
M1906F9S. A Redmi A3 will not carry that number.Have the back opened by a technician
The Mi A3 is a sealed phone and its glass back is usually glued. Do not try to lift it at home. The technician reads
BM4Ffrom the cell sticker.Compare old and new packs side by side
Check the code, the capacity line, the connector shape and the weight before the new pack goes in.
Redmi A3 battery model: why it is a separate answer
Listings mostly code the budget Redmi A3, with its 5000 mAh cell, as BN5R, while the Mi A3 is an older Android One phone with a cell about a thousand mAh smaller. The two packs are different in code, size and capacity, so neither can stand in for the other.
The full story for the Redmi A3 is on the BN5R page, which also lists its twin phones. Here, keep one rule in mind: the word before A3 decides the battery.
A student came in with a Mi A3 that lasted just half a day. The shop had an "A3" pack ready, and it was a BN5R. The technician read M1906F9SH on the box and asked for BM4F. The wrong pack would have wasted a trip.
Capacity of the Mi A3 pack: typical and rated
BM4F's 4030 mAh is the typical figure used in Mi A3 adverts. Makers also print a slightly lower rated capacity on the cell sticker, and that number is the one to read from your own pack, since a listing may not copy it.
For BM4F watt hours, take 4030 mAh, multiply by the printed volts, and divide by a thousand. A Mi 9 Lite pack at another voltage would store different energy even at 4030 mAh, so compare the full label.
Mi A3 screen time depends on brightness, signal, apps and the age of BM4F. An older Mi A3 with a worn pack may give far less than the 4030 mAh suggests, which is a sign of wear and not of a wrong code.
Where to see the code before ordering
On the sealed Mi A3, Settings does not show BM4F. The BM4F sticker on the cell is the real source. Before that, you can narrow things down from outside the phone:
- The Mi A3's retail box shows its name and model number.
- Under About phone the model number is shown, or search for model in Settings.
- A service record or old repair slip may carry the battery code.
Photograph the BM4F sticker clearly once the back is open. It helps if the repair has to be redone. Our code finding guide covers the general steps.
Ask for the model number to be written on the order, with BM4F beside it. Two matching items on paper stop most counter mistakes.
Signs the Mi A3 pack is tired
| Mi A3 sign | Why | BM4F action |
|---|---|---|
| Percentage jumps down quickly | Worn cell, many charge cycles | Check Mi A3 health, then plan a BM4F |
| Mi A3 turns off with charge left | Tired BM4F under load | Ask Xiaomi service to measure BM4F |
| Mi A3 screen lifts from the frame | BM4F swelling from inside | Stop using the Mi A3 and visit today |
| Mi A3 warm while idle | Worn BM4F or runaway app | Restart the Mi 9 Lite, remove its cover, test BM4F |
On the Mi A3, check apps and weak signal first with our drain explainer. After that, try the health check steps.
Swelling, heat, leaks or dents make BM4F a fire hazard. Unplug the Mi A3, keep pressure off the cell, cool it and bring it to Xiaomi service. BM4F fakes often print far above 4030 mAh, so choose BM4F and nothing else.
Fitting a new BM4F pack and caring for it
The glued back and the sealed body make this a job for a repair shop you trust, or the maker's own service point. Tell them the phone name, then the model number, then BM4F. Fitting tips for every phone are in our swap guide.
Judge a BM4F copy by weight, print and batch marks:
- It weighs less than the old BM4F.
- BM4F lettering is smeared with no batch line.
- It boasts well over 4030 mAh in the same size.
After the swap, charge with the original charger, avoid leaving the phone in a hot car and do not sleep with it under the pillow while charging. A cooler pack ages slower.
Other Xiaomi codes that look close
At the counter, codes such as BM5R and BN5R are easily confused with BM4F because the letters are close. The BM5R page lists that code's own phones; read it before accepting such a pack. All Xiaomi group codes are in our Redmi and POCO list.
Frequently asked questions
What is the Mi A3 battery model?
Listings give the Mi A3 battery model as BM4F, at 4030 mAh typical. Confirm by reading the BM4F sticker on your own cell.
What is the Redmi A3 battery model?
Most listings give the Redmi A3 the code BN5R at 5000 mAh typical. It is a separate pack from the Mi A3 and cannot replace it.
Can I fit a Redmi A3 battery in a Mi A3?
No. The codes, sizes and capacities differ. Fit only a pack that carries the same code as the old one.
How many mAh is the Mi A3 battery?
Sellers give BM4F 4030 mAh typical. BM4F's rated figure may be slightly lower; check your own label.
Is the Mi A3 battery removable?
No. The Mi A3 is sealed and its back is usually glued. A technician should open it, not the owner.
Does the Mi 9 Lite use the same battery as the Mi A3?
Most listings show the same BM4F code for both, but check the sticker before ordering.