Polaroid PROZ500PR003 Compatible Battery 3.7V 950mAh

Polaroid Pro Z500 / PROZ500PR003 — 3.7V Li-ion Replacement Battery

This is a 3.7V, 950mAh Li-ion battery for the Polaroid PROZ500PR003 smartphone, also sold as the Pro Z500 and Pro 003. It replaces the original cell when capacity has dropped or the battery no longer holds a charge. Voltage and connector match the stock unit — no modifications needed to install.

• PROZ500PR003 / Pro Z500 / Pro 003 compatibility: All three model designations reference the same hardware platform, sharing the same battery bay geometry, connector pinout, and BMS communication protocol. One cell covers all three variants.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Polaroid Pro Z500 platform. The BMS accepted the cell without error flags, and the charge IC ramped to full current within the first cycle.
• Fuel gauge recalibration on first use: On the first use after installation, run one complete discharge down to auto-shutdown, then charge to 100% uninterrupted. This lets the fuel gauge IC map its coulomb counter to the new cell's discharge curve and prevents early erratic percentage readings.

Why the Polaroid Pro Z500 reports wrong battery percentage after a cell swap

The fuel gauge IC on this phone uses a stored discharge curve calibrated to the original cell. When a new cell goes in, the IC is still reading against the old curve, so the percentage shown on screen drifts from actual cell state. This is not a fault with the replacement cell — it is the IC recalibrating. One full discharge-to-shutdown followed by a full uninterrupted charge resets the coulomb counter. After that cycle, percentage reporting stabilises.

Sudden shutdown at 20–30% remaining on the replacement cell

This shutdown pattern points to a voltage cliff — under modem or screen load, the cell voltage drops sharply below the BMS cutoff threshold before the fuel gauge reaches zero. It typically happens when the gauge IC hasn't completed recalibration and the phone cuts power at what it still thinks is a safe state of charge. Run one complete discharge cycle to auto-shutdown without interruption. If the shutdowns continue after two full cycles, check that the battery contacts are clean and fully seated — poor contact raises internal resistance and steepens the voltage sag under load.