Polaroid PROZ500PR003 Replacement Battery 3.7V 1200mAh

Polaroid Pro Z500 — 3.7V Li-ion Replacement Battery

This 3.7V, 1200mAh lithium-ion cell is a direct replacement for the Polaroid PROZ500PR003 smartphone. It restores power to a handset that no longer holds adequate charge through calls, messaging, and app use. Fit models include the Pro Z500 and Pro 003 variants.

• Pro Z500 and Pro 003 compatibility: These models share an identical 3.7V single-cell architecture, connector pinout, and BMS handshake protocol — the same replacement cell covers both without modification.
• Bench tested on actual hardware: We cycled this cell on the PROZ500PR003 platform, confirming the BMS accepted the new cell on first boot, charge termination triggered correctly at 4.2V, and the protection circuit responded to simulated over-discharge.
• Fuel gauge recalibration after installation: On first use, disable any fast-charging mode and run one complete discharge-to-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the replacement cell

This happens because the fuel gauge IC is still running the discharge curve it learned from the original, degraded cell. When the new cell's voltage drops under modem or screen load, the gauge misreads remaining capacity and triggers a low-voltage shutdown earlier than expected. The fix is a full calibration cycle: charge to 100%, let the phone discharge naturally to auto-shutdown, then charge back to 100% without interruption. After one complete cycle the gauge recalibrates and shutdowns at low percentages stop.

Phone warm near the battery compartment during first charge

A fresh high-impedance cell generates more heat during initial charging than a broken-in cell. The charge IC pushes current into a cell with higher internal resistance, which dissipates as heat until the first few cycles lower that impedance. Keep the phone out of its case for the first charge. If warmth progresses to hot or charging stops before 100%, check that the charge IC has not entered a thermal-protection pause — unplug for five minutes and restart the charge.