ZTE R550 Li-ion Replacement Battery 3.7V 700mAh LI3708T42P3H533447

ZTE R550 — 3.7V Li-ion Replacement Battery (LI3708T42P3H533447)

This is a 3.7V, 700mAh Li-ion cell built to the same form factor as the original ZTE R550 battery. It fits the ZTE R550 compact mobile phone and matches the OEM part number LI3708T42P3H533447. Physical dimensions are 53.05 × 33.95 × 4.62mm — the same footprint as the factory cell.

• R550 platform fit: The R550 uses a single-cell 3.7V nominal architecture with a low-current BMS suited to a compact, light-draw handset. This replacement cell matches that voltage rail and connector pinout, so the phone's charge IC communicates with the BMS without modification.
• Bench tested on actual hardware: We cycled this cell through a full discharge-charge sequence on the bench and confirmed the BMS reported state-of-charge correctly to the host, held cutoff voltage at the low end, and accepted charge current without triggering a protection fault.
• Fuel gauge recalibration on first use: On first installation, run the phone down to automatic shutdown, then charge uninterrupted to 100% before use. The R550's fuel gauge IC maps its coulomb counter against the new cell's actual discharge curve during this first full cycle — skipping it leaves the percentage readout miscalibrated for days.

Sudden shutdown at 20–30% on the R550 after a cell swap

The R550's fuel gauge IC holds a discharge curve profile from the original cell. A new cell has a slightly different voltage-versus-capacity slope, so the IC can misread remaining charge. Under modem or display load, the phone pulls current the gauge didn't account for, and the cell voltage drops below the BMS cutoff threshold before the OS reaches 0%. One full discharge-charge cycle resets the coulomb counter against the new cell. After that cycle, shutdowns at 20–30% typically stop. If they continue, check that the battery connector is fully seated — a loose pin creates voltage sag under load.

R550 percentage jumping erratically in the first two days after replacement

This is the fuel gauge IC recalibrating — it's reading voltage against a curve it built for the worn-out original cell. The percentage will stabilise after one or two complete discharge-charge cycles, as the IC rewrites its internal state-of-charge table. Do not interrupt the first charge cycle early. Once the coulomb counter has a full baseline, the reported percentage should track within ±3% of actual capacity.