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Pocophone BM4E Poco F1 Compatible Battery 3.85V 3900mAh

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Fits Poco F1 and Armoured Edition models; replaces OEM part BM4E directly.
3.85V, 3900mAh lithium-polymer cell matches the fuel gauge IC calibration window for this device.
Connector slides into the battery bay with the contact pad facing the logic board; no locking tab.
We charged this cell on a calibrated bench supply and logged stable voltage ramp with clean BMS handoff at 4.2V cutoff.
On first use after installation, disable fast charging for one complete discharge-charge cycle — this lets the fuel gauge IC recalibrate against the new cell discharge curve before USB-PD pushes current into an uncalibrated cell.
Delivery time

This product ships directly from our Manufacturer's Warehouse and is usually delivered within 7 – 10 business days to your doorstep.

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Fresh Battery, Worth the Wait

To provide the highest-quality replacement battery, we ship this battery directly from the manufacturer rather than from aging warehouse inventory. This means delivery may take a little longer, but it helps ensure you receive a fresh battery with better performance, a longer lifespan, and greater reliability.

Estimated delivery: 7–10 business days
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Battery Care Tips

🔹 Getting Started

Charge your new battery fully before you use it for the first time. Over the next few charge cycles, run your device down to around 20% before you recharge—this helps the battery perform its best. After that, charge whenever you need to.

🔹 Keep It Healthy

Avoid letting your battery completely drain or staying plugged in constantly. Both extremes wear it out faster. Store the battery in a cool, dry place when you're not using it, since heat damages batteries quickly.

Delivery and Shipping

🔹 Most orders ship the next day, and we use FedEx, UPS, Purolator and other carriers to get them to you. Lithium batteries have to ship by ground only, not air or USPS. Make sure your address is right before you order, because if we have to send it back, you pay for shipping again.

Disclaimer

⚠️ Disclaimer: All product names, trademarks, and registered trademarks belong to their respective owners.

🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

Voltage

3.85V

Amp

3900mAh

Pocophone Poco F1 — 3.85V Li-Polymer Replacement Battery (BM4E)

This is a 3900mAh (15.02Wh) Li-Polymer cell built to replace the OEM BM4E battery in the Pocophone Poco F1 and Poco F1 Armoured Edition. It fits both the standard global dual SIM and TD-LTE variants, including devices registered under model number M1805E10A. Voltage is 3.85V nominal, matching the Poco F1's power management IC spec.

  • Poco F1 and Armoured Edition fit: Both variants share the same battery bay dimensions, connector pinout, and BMS handshake protocol. The BM4E form factor — 85.20 × 64.00 × 4.02mm — seats directly into either chassis without modification.
  • Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Poco F1 board. The BMS negotiated correctly with the Snapdragon 845's power management IC, and protection cutoffs triggered at expected thresholds under load.
  • Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map its coulomb counter to the new cell's actual discharge curve before high-current charging begins on an uncalibrated cell.

Sudden shutdown at 20–30% on the Poco F1 after a cell swap

This happens because the fuel gauge IC is still using the discharge curve from the old, degraded cell. The new cell holds a steeper voltage drop near its lower capacity range, and the gauge misreads remaining charge. Under modem or display load, actual cell voltage drops below the BMS cutoff before the percentage counter reaches zero. Run one full discharge to below 5% and a complete charge to 100% with fast charging off — this forces the coulomb counter to re-anchor to the new cell's curve.

USB fast charge not activating on the first cycle after replacement

The Poco F1 uses Qualcomm Quick Charge 3.0 negotiation between the charge IC and the battery BMS. On the first cycle with a new cell, the BMS may not complete its handshake in time for the charger to step up voltage, so the device defaults to standard 5V charging. This is not a fault in the battery or charger. Complete one full standard charge cycle first, then Quick Charge negotiation typically resumes normally on the next session.

Compatible Models

Poco F1 Poco F1 Armoured Edition Global Dual SIM Poco F1 Armoured Edition Global Dual SIM TD-LTE M1805E10A

Replaces Part Numbers

BM4E

Technical Specifications

Voltage3.85V
Amp Hours3900mAh
Capacity3900mAh
Rate15.02Wh
Net Weight53.2g /1.88 oz
Gross Weight88g /3.10 oz
Approximate Weight88g /3.10 oz
Dimension 85.20 x 64.00 x 4.02mm

Product Highlights

  • Brand: Pocophone
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Li-Polymer
  • Battery Type: Li-Polymer
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My Poco F1 shows 25% battery and then just cuts off with no warning — is the new cell faulty?

The cell is not faulty. The fuel gauge IC calibrated its discharge model against your old degraded cell, so it doesn't know where the new cell's voltage cliff sits under load. When the modem or screen pulls current, real cell voltage drops below the BMS cutoff threshold before the percentage display catches up. Do one full discharge to under 5% and a slow charge to 100% with Quick Charge disabled — after that cycle, the percentage readings will track correctly.

The phone feels warm near the back panel while charging the new BM4E — is something wrong?

A fresh Li-Polymer cell has higher internal impedance than a broken-in cell, so the charge IC works harder pushing current through it on the first few cycles. That generates more heat than you'd see with the old, lower-impedance cell. Keep the phone out of a case during the first two or three charges to let heat dissipate, and avoid charging on soft surfaces. Warmth drops off noticeably once the cell has completed three to five full cycles.

My Poco F1 won't power on at all after the new battery sat in a drawer for a few months before installation — how do I recover it?

If cell voltage dropped below approximately 2.5V during storage, the BMS enters lockout mode to prevent charging a potentially unsafe cell. Plug into a 5V charger — not a Quick Charge adapter — and leave it connected for 15 to 30 minutes without attempting to power on. The charge IC will trickle current into the cell at a low rate to bring voltage back above the BMS recovery threshold, typically around 3.0V, after which normal charging resumes automatically.

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