Navon G55132 Mizu M502 Replacement Battery 3.8V 2000mAh

Navon Mizu M502 / D502 — 3.8V Li-Polymer Replacement Battery (G55132)

This 3.8V, 2000mAh lithium-polymer battery replaces the OEM G55132 cell in the Navon Mizu M502 and Mizu D502 smartphones. Both models share the same battery bay dimensions and connector, making this a direct physical match at 76.90 × 59.00 × 4.04mm. Capacity is 7.6Wh — identical to the original spec.

• Mizu M502 and D502 compatibility: Both the M502 and D502 run the same voltage rail and use the same G55132 footprint. The connector pinout and BMS handshake are identical across both models, so one cell covers the full pair.
• Bench tested on actual hardware: We cycled this cell through charge and discharge under screen-on and modem-active load conditions. The BMS held cutoff correctly at both ends — no early shutdown during the test sequence.
• Fuel gauge recalibration on first use: On first installation, disable fast charging and run one full discharge-to-charge cycle before resuming normal use. The fuel gauge IC on the Mizu M502 calibrates its coulomb counter against the cell's discharge curve — skipping this step causes the percentage to read inaccurately for the first several cycles.

Sudden shutdown at 20–30% on the Mizu M502 after a cell swap

This happens when the fuel gauge IC is still calibrated to the old cell's discharge curve. The new cell's voltage drops faster under modem or display load than the IC expects, so it trips the low-voltage cutoff while still reporting 20–30% remaining. It is not a fault with the replacement cell. Run two full discharge-charge cycles without fast charging, and the coulomb counter will remap to the new cell's actual voltage profile.

Phone warm near the battery slot during the first charge after installation

A new lithium-polymer cell typically has higher internal impedance than a well-used one. During the first charge, the charge IC pushes current into that higher impedance, which generates more heat than normal. This is expected on cycle one and should reduce noticeably by cycle two or three. If the phone remains hot beyond the third full charge, check that the charge current has not been set above 1C — on the Mizu M502, that means staying at or below 2000mA input during charging.