Palmax Z720 GPS Navigator Replacement Battery 3.7V 1300mAh

Palmax Pocket PC Z720 — 3.7V Li-Polymer Replacement Battery (BALL-N911-DMED)

This 3.7V 1300mAh Li-Polymer cell replaces the original battery in the Palmax Pocket PC Z720 handheld GPS navigator and pocket computer. It matches the OEM part number BALL-N911-DMED and restores full power to the unit. Capacity is 4.81Wh — identical to the original specification.

• Pocket PC Z720 fit: The Z720 uses a single Li-Polymer cell on a 3.7V rail with a straightforward connector. No BMS handshake is required between the battery and the device — the Z720 manages charge and discharge protection internally through its own circuit board, so cell voltage and chemistry are what matter for compatibility.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a GPS navigation load profile. The cell held stable voltage across both active satellite acquisition and display-on navigation use, and the protection circuit tripped cleanly at the low-voltage cutoff threshold without dropping mid-session.
• First fix after battery swap: After fitting this cell, power the Z720 on outdoors and let it acquire a satellite fix before using navigation. The unit performs a cold start after any full power interruption — first fix typically takes 5–10 minutes. Subsequent warm starts run under a minute.

GPS accuracy reduced as the Z720 battery depletes

Some GPS units step down receiver sensitivity when battery voltage drops below a threshold — the Z720 is no exception. The GPS chipset draws meaningful current during active satellite tracking, and the device may reduce receiver gain to extend operation at lower states of charge. The practical result is that position accuracy degrades before the unit shuts off. Keeping the battery above roughly 3.5V under load maintains full receiver performance.

Z720 shuts off without warning before the low battery indicator appears

This happens when the battery indicator is calibrated to the old, degraded cell rather than the new one. The Z720 reads remaining charge based on voltage curves, and a fresh cell discharges along a flatter voltage curve than a worn one — the indicator can read higher than actual capacity until the cutoff voltage is reached abruptly. Run two or three full charge and discharge cycles on the new cell so the device recalibrates its voltage-to-charge mapping. After that, the low battery warning should appear at the correct threshold.