About this replacement
ZTE U950 / V955 / U960S3 — 3.7V Li-Polymer Replacement Battery (Li3720T42P3h585651)
This is a 3.7V, 2000mAh Li-Polymer cell built to the Li3720T42P3h585651 specification. It fits the ZTE U950, V955, U960S3, and N880G, among others in the same platform family. The cell measures 57 × 54 × 4mm — match your original before installation.
- U950 / V955 platform fit: These models share the same battery bay dimensions, connector pinout, and BMS handshake protocol. One cell covers the full group without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the U950 platform. The BMS accepted the cell, charge termination triggered correctly at 4.2V, and the protection circuit held cutoff at the expected low-voltage threshold without tripping prematurely.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one full discharge-charge cycle. The fuel gauge IC is calibrated to the old cell's discharge curve. Running one slow cycle lets it recalibrate against the new cell before high-current charging pushes current into an uncalibrated state.
Sudden shutdown at 20–30% on the ZTE U950 after a cell swap
The U950's fuel gauge IC stores a learned discharge curve from the original cell. When a new cell goes in, that curve no longer matches the actual voltage drop under load. The modem and display draw a combined spike that causes the cell voltage to dip below the BMS cutoff threshold even while the OS still reports 20–30% remaining. The phone interprets this as a hard fault and shuts down. One full slow discharge-charge cycle forces the coulomb counter to relearn the new cell's actual capacity curve and corrects the shutdown behaviour.
Phone shows wrong battery percentage after replacement
The OS percentage display is driven by the fuel gauge IC, not a direct voltage reading. After a cell swap, the IC is still mapping charge state against the old cell's impedance and self-discharge profile. This causes percentage figures to jump, stall, or freeze at values like 99% or drop suddenly. Drain the phone until it shuts off, then charge uninterrupted to 100% on a standard 5V charger — this resets the coulomb counter and re-anchors the gauge to the new cell's actual endpoints.