Asus Halley SBP-02 Replacement Battery 3.7V 1100mAh

Asus Halley / Jupiter — 3.7V Li-ion Replacement Battery (SBP-02)

This is a 3.7V, 1100mAh Li-ion replacement battery for the Asus Halley and Asus Jupiter smartphones. It slots in where the original SBP-02 cell sits and restores power to the device. Capacity figure is taken from the product specification — 4.07Wh.

• Halley and Jupiter shared platform: Both phones run the same voltage rail and use the same SBP-02 connector pinout with an identical BMS handshake, which is why one cell covers both models. Swap one in on either device and the charge IC recognises it without modification.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the bench. The BMS held charge termination at the correct 4.2V cutoff and the protection circuit tripped cleanly at the low-voltage threshold — no runaway, no false cutoffs mid-cycle.
• 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 is applied to an uncalibrated cell — prevents erratic percentage readings from the first day.

Sudden shutdown at 20–30% on a fresh SBP-02 cell

A new cell shutting the phone down at 20–30% is a voltage cliff problem, not a capacity problem. Under modem or screen load, the cell voltage drops sharply in that lower charge band — faster than the fuel gauge IC expects. The phone's low-voltage protection kicks in and cuts power before the gauge reaches zero. One full slow-charge calibration cycle usually brings the reported cutoff voltage in line with actual cell behaviour.

Phone will not power on after the SBP-02 sat in storage

Li-ion cells stored for extended periods can self-discharge below 2.5V per cell, which triggers BMS lockout — the protection circuit opens and blocks all current flow to prevent damage. A phone in this state will show no response to the power button and no charge indicator on plug-in. Connect it to a charger and leave it for 20–30 minutes without pressing anything — the charge IC on the phone board delivers a trickle current to bring the cell above the 2.5V recovery threshold. Once voltage clears that floor, the BMS re-initialises and normal charging resumes.