About this replacement
Samsung Galaxy Note 3 SM-N900 / SM-N9005 — 3.8V Li-ion Replacement Battery (B800BE)
This is a 3200mAh, 3.8V lithium-ion cell that replaces the original B800BE battery in the Samsung Galaxy Note 3. It fits the SM-N900 and SM-N9005 variants, along with Galaxy Note III hardware sold under regional model numbers. The cell matches the original's physical dimensions at 80.60 × 53.40 × 5.30mm and slots into the same removable battery bay.
- SM-N900 and SM-N9005 compatibility: Both variants use the same B800BE form factor, voltage rail, and connector orientation. The BMS communication between battery and charge IC is identical across these two boards, so the same cell covers both without modification.
- Bench tested on actual hardware: We ran this cell on an SM-N9005 board and confirmed the BMS handshake completed correctly, charge IC accepted the cell without error flags, and cutoff voltage held at the expected low-cell threshold under load.
- Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging and run one full discharge down to auto-shutdown, then charge to 100% on standard current. This lets the coulomb counter recalibrate against the new cell's discharge curve before high-current charging pushes current into an uncalibrated state.
Why the Note 3 reports wrong battery percentage after a cell swap
The Galaxy Note 3 uses a fuel gauge IC that tracks charge state by counting coulombs against a learned discharge curve from the old cell. When you install a new cell, that stored curve no longer matches the actual cell chemistry, so the reported percentage drifts — often reading full when the cell is partially charged, or dropping suddenly near 20–30%. One complete discharge-charge cycle on standard current rewrites the learned curve to match the new cell. After that cycle, percentage readings stabilise.
Sudden shutdown at 20–30% on the replacement cell
This is a voltage cliff issue, not a capacity fault. Under heavy load — modem transmitting, screen at full brightness, or a background sync burst — the cell voltage drops sharply below the threshold the charge IC uses to trigger shutdown, even though the fuel gauge still shows charge remaining. The fuel gauge and the actual cell voltage diverge when the coulomb counter is running an old calibration. Run one full discharge to auto-shutdown, then charge to 100% at standard current; the fuel gauge IC re-anchors its low-voltage cutoff estimate to the new cell's actual curve. Shutdowns at mid-percentage should stop after that single calibration cycle.