About this replacement
Lenovo PHAB PB1-750 Series — 3.8V Li-Polymer Replacement Battery (L15D1P32)
This is a 3.8V, 4250mAh Li-Polymer replacement battery for the Lenovo PHAB 6.98 and PB1-750 series. It fits the PB1-750, PB1-750N, and PB1-750M variants using OEM part number L15D1P32. If your PHAB no longer holds a charge through a normal day of use, this cell is the direct hardware fix.
- PB1-750 variant compatibility: The PB1-750, PB1-750N, and PB1-750M all run the same 3.8V power rail with an identical connector footprint and BMS handshake protocol. One cell covers all three without hardware modification.
- Bench tested on actual hardware: We ran this cell through a full charge and discharge cycle on a PB1-750 unit. The BMS accepted the cell without fault codes, and the charge IC stepped through trickle, constant-current, and constant-voltage phases cleanly.
- Fuel gauge recalibration on first install: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging pushes current into an uncalibrated cell.
Sudden shutdown at 20–30% on the PHAB after a cell swap
This happens because the fuel gauge IC is still running the discharge curve it learned from the old, degraded cell. The new cell has a steeper voltage drop under screen or modem load than the IC expects at that state-of-charge. The device hits the hardware undervoltage cutoff before the software percentage reaches zero. One full slow discharge-charge cycle forces the IC to relearn the curve against the new cell and eliminates the false cutoff.
USB charging not recognised on the first cycle after replacement
A freshly installed Li-Polymer cell can sit below the charge IC's minimum acceptance threshold if it has been in storage. The BMS will block the charge path entirely until the cell voltage climbs above approximately 2.5V per cell. Connect the PHAB to a 5V/1A charger — not a fast charger — and leave it for 20–30 minutes without attempting to power on. Once the BMS detects the cell has recovered above threshold, normal charging resumes automatically.