About this replacement
Elephone P9000 Series — 3.8V Li-Polymer Replacement Battery (P9000)
This is a 3.8V, 3000mAh (11.4Wh) lithium-polymer cell for the Elephone P9000 smartphone. It fits the standard P9000, P9000 Dual SIM LTE, and P9000 Lite variants. All three models use the same battery footprint, connector, and BMS handshake.
- P9000, P9000 Dual SIM LTE, P9000 Lite compatibility: These three variants share a common voltage rail at 3.8V nominal and an identical physical connector with the same BMS pin-out. Swapping between them requires no wiring changes — the fuel gauge IC on each board reads the same cell chemistry identifiers.
- Bench tested on actual hardware: We cycled this cell through charge and full-draw discharge on the P9000 board. The BMS accepted the cell without fault flags, the charge IC stepped cleanly through CC and CV phases, and the coulomb counter registered expected capacity without manual reset.
- 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 the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell — preventing erratic percentage readings from the first day.
Sudden shutdown at 20–30% on the replacement cell
The P9000's fuel gauge IC retains the discharge curve from the old, degraded cell. When a new cell is installed, the IC underestimates how much charge remains at any given voltage. Under high-draw loads — modem handoff, screen-on bursts, GPS — the cell voltage drops below the cutoff threshold faster than the IC predicts. The phone interprets this as a dead cell and shuts down, even though charge remains. Run one full discharge to below 5% and a full charge to 100% without interruption to let the coulomb counter recalibrate to the new cell.
USB-PD fast charge not triggering on the first cycle after replacement
After a cell swap, the charge IC on the P9000 can default to standard 5V/1A input until the BMS reports a verified cell state. This is a protection behaviour — the controller will not negotiate higher voltage until it confirms cell temperature and impedance are within range. On the first charge, use a standard 5V charger and allow a full cycle to complete. On the second charge, the fast-charge handshake should resume normally at the expected input voltage.