About this replacement
ZTE U956 — 3.8V Li-Polymer Replacement Battery (LI3825T43P3H755544)
This is a 3.8V, 2500mAh lithium-polymer replacement battery for the ZTE U956 smartphone. It carries OEM part number LI3825T43P3H755544 and slots directly into the U956 battery bay. Rated at 9.5Wh, it matches the original cell's voltage and capacity spec.
- U956 platform fit: The U956 uses a 3.8V Li-Polymer cell with a specific connector pitch and BMS handshake tied to the phone's charge IC. This replacement matches that connector and communicates with the fuel gauge IC so the OS reads state-of-charge correctly after calibration.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the U956 platform. The BMS accepted the charge protocol without fault, and the fuel gauge IC stabilised within one full cycle — no erratic percentage jumps after that first complete discharge.
- Fuel gauge recalibration on first use: After fitting this cell, disable fast charging for the first complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging begins. Skipping this step is the main reason users see incorrect percentage readings after a swap.
Sudden shutdown at 20–30% on the U956 after a cell swap
This is a voltage cliff problem, not a capacity fault. The U956's modem and display draw sharp current spikes, and if the fuel gauge IC is still calibrated to the old cell's discharge curve, it misreads state-of-charge. The phone thinks it has 25% left, but the cell voltage drops below the BMS cutoff threshold under load — typically around 3.2V — and the phone cuts out instantly. One full discharge-charge cycle recalibrates the coulomb counter to the new cell and eliminates the false cutoff.
Phone warm near the battery during the first few charge cycles
A new Li-Polymer cell starts with slightly higher internal impedance than a broken-in cell. The U956's charge IC pushes constant current into this higher-impedance cell, which generates more heat than you'd see on a used battery. This is normal for the first two to three cycles and settles as impedance drops. If the phone stays warm past cycle three or gets hot to the touch, check that the battery contacts are clean and seated flush — a poor contact forces the charge IC to work harder.