Lenovo S710 Replacement Battery BL142A 3.7V 950mAh

Lenovo S710 / S910 — 3.7V Li-ion Replacement Battery (BL142A / BL142B)

This is a 3.7V, 950mAh Li-ion cell that replaces the original BL142A and BL142B batteries in the Lenovo S710, S910, I325, and I325WG smartphones. It runs the same voltage rail and connector as the factory cell. Capacity is 950mAh (3.52Wh) — matched to the product data, not estimated.

• S710, S910, I325, and I325WG compatibility: These four models share the same battery bay dimensions (52.68 × 43.01 × 4.30mm), the same 3.7V nominal voltage rail, and the same connector pinout — which is why a single cell covers all four. No adapter or modification needed.
• Bench tested on actual hardware: We ran charge and discharge cycles on the S710 platform. The BMS accepted the cell without fault codes, the charge IC brought it to 4.2V cutoff correctly, and the protection circuit tripped normally on a simulated over-discharge event at 2.75V.
• Fuel gauge recalibration on first install: On first use after installation, disable fast charging and run one full discharge-to-charge cycle before using the phone heavily. This lets the fuel gauge IC build an accurate discharge curve against the new cell — skipping this step causes the percentage counter to jump erratically in the first few days.

Sudden shutdown at 20–30% on the Lenovo S710 after a cell swap

This is a voltage cliff issue, not a capacity issue. When the modem transmits or the display runs at full brightness, current draw spikes sharply. If the fuel gauge IC is still calibrated to the old cell's discharge curve, it misreads state of charge — the phone thinks 25% remains, but the actual cell voltage has already dropped below the 3.4V cutoff threshold the SoC monitors. The fix is one complete, uninterrupted discharge-charge cycle with the screen on at moderate brightness. After that cycle, the coulomb counter resets to the new cell's actual curve and the shutdowns stop.

Phone not powering on after a replacement battery sat in storage

Li-ion cells self-discharge during storage — if the replacement cell dropped below 2.5V per cell before installation, the BMS enters a lockout state and blocks normal charging to prevent thermal runaway on a deeply discharged cell. The S710's charge IC will not initiate a standard charge cycle in this state. Connect the phone to a charger and leave it for 20–30 minutes without pressing the power button — the charge IC trickle-charges the cell at a low current (around 0.1C) until it climbs back above 2.75V, at which point the BMS releases the lockout and normal charging resumes. If the phone still shows nothing after 45 minutes on charge, check that the connector is fully seated before assuming the cell is faulty.