Xiaomi BN36 Mi 6X Replacement Battery 3.85V 3000mAh
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Xiaomi BN36 Mi 6X Replacement Battery 3.85V 3000mAh - is backordered and will ship as soon as it is back in stock.
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Battery Care Tips
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
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
⚠️ 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.
Xiaomi BN36 Mi 6X Replacement Battery 3.85V 3000mAh - is backordered and will ship as soon as it is back in stock.
Voltage
3.85V
Amp
3000mAh
Xiaomi Mi 6X / Mi A2 — 3.85V Li-Polymer Replacement Battery (BN36)
This is a 3000mAh, 3.85V Li-Polymer replacement battery for the Xiaomi Mi 6X and Mi A2 smartphones. It uses OEM part number BN36 and fits the standard Mi 6X body cavity at 85.08 x 64.50 x 3.45mm. It restores capacity to devices that have degraded through charge cycles or age.
- Mi 6X and Mi A2 compatibility: Both devices share the same PCB layout, battery connector pinout, and BMS handshake protocol. The Mi A2 is the global variant of the Mi 6X — same chassis, same battery slot, same BN36 spec.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on Mi 6X units. The BMS accepted the cell without error flags, and the fuel gauge IC tracked state-of-charge without interruption across the test cycles.
- First-cycle fast charge protocol: 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's discharge curve before high-current charging pushes into an uncalibrated state.
Why the Mi 6X reports wrong battery percentage after a cell swap
The Mi 6X uses a coulomb counter in the fuel gauge IC that tracks charge based on the previous cell's discharge curve. When a new cell goes in, that stored curve no longer matches the actual cell chemistry. The IC keeps using the old reference, which causes the displayed percentage to lag or jump. One full discharge-to-shutdown followed by a complete charge to 100% forces the IC to rewrite its calibration against the new cell.
Sudden shutdown at 20–30% on the replacement cell
This happens when the cell voltage drops below the BMS cutoff threshold under load — typically during modem activity, screen-on bursts, or app wake cycles. The fuel gauge still reads 25%, but the cell cannot sustain the voltage rail under that current draw. The BMS trips as a protection event, not a capacity failure. Charge the phone fully, then run one complete cycle without fast charging — if shutdowns stop, the fuel gauge has recalibrated. If they continue, check that the cell connector is fully seated and making clean contact.
Compatible Models
Replaces Part Numbers
Technical Specifications
Product Highlights
- Brand: Xiaomi
- Manufacturer: CS
- Series: X-Longer
- Color: Black
- Product Type: Li-Polymer
- Battery Type: Li-Polymer
- Warranty: 12 Months
- Bulk Orders: sales@batteryweb.com
Frequently Asked Questions
My Mi 6X won't turn on at all after the replacement battery sat in a drawer for a few months — is the battery dead?
The BMS locks out when cell voltage drops below approximately 2.5V from prolonged storage discharge. The phone will not respond to a normal power-on attempt. Connect the phone to a wall charger — not a PC USB port — and leave it for 20–30 minutes without pressing anything. The charge IC on the phone will trickle current into the cell until the BMS re-enables. Once voltage recovers above the threshold, the phone will boot normally.
Fast charging stopped working on my Mi 6X after I installed this battery — it only charges slowly now.
Xiaomi's proprietary charge protocol requires a BMS handshake before the charge IC ramps to high current. On the first cycle with a new cell, the handshake sometimes fails because the fuel gauge IC has no baseline data yet. Complete one full slow charge to 100%, then discharge normally and charge again — the protocol re-negotiates on the second cycle. If fast charging still does not activate, check that the USB cable supports the current rating for Xiaomi's fast charge spec.
The battery percentage on my Mi 6X keeps jumping — it reads 60%, drops to 40%, then jumps back — what's causing that?
The coulomb counter in the fuel gauge IC is recalibrating against the new cell's discharge curve and has not yet built a stable reference. This is normal for the first two to three cycles after a replacement. Run two full discharge-to-shutdown and charge-to-100% cycles with fast charging disabled. After that, the IC will have enough data to track state-of-charge accurately and the jumping should stop.
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