Asus P552w Replacement Battery SBP-18 3.7V 1100mAh

Asus P552w / P552v — 3.7V Li-ion Replacement Battery (SBP-18)

This is a 3.7V, 1100mAh Li-ion cell sourced to the SBP-18 specification for the Asus P552w and P552v smartphones. It replaces an original cell that has degraded, swollen, or stopped holding a charge. Dimensions are 52.35 × 42.58 × 5.36mm — verify against your existing cell before installation.

• P552w and P552v compatibility: Both models share the same battery bay geometry, connector pinout, and SBP-18 part number. The voltage rail and BMS handshake are identical across the two, so one cell covers both variants.
• Bench tested on actual hardware: We ran charge and discharge cycles through a P552w unit. The BMS accepted the cell without fault codes, charge current stepped down correctly at top-of-charge, and the protection circuit tripped cleanly at the low-voltage cutoff threshold.
• First-cycle calibration on the P552w: 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 current into an uncalibrated cell — it reduces erratic percentage readings in the first few days.

Sudden shutdown at 20–30% on the P552w after a cell swap

The P552w fuel gauge IC builds its discharge model from the previous cell's coulomb-count history. After a swap, that model no longer matches the new cell's actual voltage curve. When the phone hits a load spike — modem transmission, screen wake — the cell voltage drops below the protection threshold faster than the IC expects, and the device cuts out even though the reported percentage looks safe. One full discharge-to-5% and uninterrupted charge cycle forces the IC to rewrite its reference curve against the new cell. After that cycle, shutdowns at falsely high percentages typically stop.

P552w not powering on after the battery has sat in storage

Li-ion cells shipped or stored for extended periods can self-discharge below 2.5V per cell. At that level the BMS locks out to prevent damage, and the phone shows nothing — no boot screen, no charging indicator. Connect the phone to a wall charger and leave it untouched for 20–30 minutes before attempting to power on. The charge IC trickle-charges the cell back above the BMS re-enable threshold, typically around 2.9V, at which point the protection circuit releases and normal charging resumes.