T-Mobile A170 LGIP-531A Replacement Battery 3.7V 800mAh

T-Mobile A170 / A180 — 3.7V Li-ion Replacement Battery (LGIP-531A)

This is a 3.7V, 800mAh Li-ion battery built to OEM part number LGIP-531A, also cross-referenced as SBPL0088801. It fits the T-Mobile A170 and A180 handsets directly, slotting into the existing battery compartment with no modification. Voltage and connector match the original factory specification.

• A170 and A180 compatibility: Both models share the same battery bay geometry, voltage rail at 3.7V, and the LGIP-531A connector pinout. The BMS handshake protocol is identical across both variants, so one cell covers either phone without firmware conflict.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the A170 platform. The BMS accepted the cell without error flags, charge current ramped correctly into CC/CV phases, and the protection circuit tripped at the expected over-discharge threshold before cell voltage could fall below safe levels.
• First-cycle fuel gauge recalibration: After installing a new cell, disable fast charging if available and run one full discharge-to-charge cycle at standard rate. The phone's fuel gauge IC is calibrated to the old cell's discharge curve — one full cycle at normal current lets it map the new cell's characteristics before high-current charging is applied.

Sudden shutdown at 20–30% on the A170 after a cell swap

The A170 uses a coulomb-counter-based fuel gauge that retains the discharge profile of the previous cell in memory. When you install a fresh 800mAh cell, the gauge's stored curve may predict a voltage floor that doesn't match the new cell's actual characteristics under modem or screen load. At high draw moments — an active call, screen at full brightness — the cell voltage dips briefly below what the gauge expects at that state of charge, and the phone interprets it as empty. One full discharge cycle down to automatic shutoff, followed by a full charge, forces the gauge IC to rebuild its reference curve against the new cell.

Phone will not power on after the replacement battery sat in storage

Li-ion cells shipped or stored for extended periods can self-discharge below 2.5V per cell. At that voltage, the BMS protection circuit trips into lockout mode and blocks current flow to prevent damage — the phone shows no charge indicator and appears completely dead. Connect the phone to a wall charger, not a USB port, and leave it for 15–20 minutes without pressing the power button. The charger's voltage can nudge the cell above the BMS re-initialisation threshold, typically around 2.9V, at which point the protection circuit resets and normal charging resumes.