Asus P320 Replacement Battery SBP-17 3.7V 1100mAh

Asus P320 / P850 — 3.7V Li-ion Replacement Battery (SBP-17)

This is a 3.7V, 1100mAh Li-ion cell replacing the original SBP-17 battery in the Asus P320 and P850 smartphones. It also fits compatible Galaxy Mini variants sharing the same footprint and connector. Swap it in when the original cell can no longer hold a usable charge through a normal day.

• P320, P850 and Galaxy Mini platform fit: These models share the SBP-17 form factor — same 60.83 × 40.41 × 4.98mm dimensions, same connector orientation, and the same 3.7V nominal voltage rail. No modification needed to seat the cell correctly.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the P320 platform. The BMS accepted the charge IC handshake on the first cycle without error, and the protection circuit tripped correctly at the low-voltage cutoff threshold during deep discharge testing.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This gives the fuel gauge IC a real discharge curve for the new cell before it starts reporting percentages to the OS — skipping this step is the main reason users see erratic percentage readings after a cell swap.

Sudden shutdown at 20–30% on the P320 after a cell swap

This happens because the fuel gauge IC is still using the discharge curve it mapped to the old, degraded cell. The new cell has a steeper voltage drop under load — modem transmit bursts and screen brightness spikes pull current the old curve never modelled. The phone sees a voltage reading that matches "20%" on the old map but is actually close to cutoff on the new cell. One full uninterrupted discharge down to shutdown, followed by a full charge, resets the coulomb counter and corrects the curve.

Phone won't power on after the SBP-17 sat discharged in storage

Li-ion cells that drop below roughly 2.5V trigger the BMS protection circuit, which opens the output and blocks normal power-on. The phone will show no response — not even a charging indicator — because the BMS is locked out before the charge IC can negotiate. Connect the phone to a wall charger and leave it for 15–20 minutes without pressing any buttons. Most charge ICs will trickle current into the cell at a reduced rate until it climbs back above the 3.0V recovery threshold, at which point the BMS resets and normal charging resumes.