Harmon Kardon GPS-500 Replacement Battery 3.7V 1500mAh

Harmon Kardon GPS-500 — 3.7V Li-Polymer Replacement Battery (320603329779)

This 3.7V, 1500mAh lithium-polymer cell replaces the original battery in the Harmon Kardon GPS-500 portable navigation unit. It matches the OEM part number 320603329779 and fits the GPS-500's battery bay at 59.62 x 36.55 x 5.94mm. Voltage and capacity are drawn directly from the product data — 5.55Wh total.

• GPS-500 fit: The GPS-500 uses a slim LiPo cell on a 3.7V single-cell rail. This replacement matches the connector orientation and physical footprint of the OEM cell, so no modification is needed to seat it.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the GPS-500 platform. The BMS handled charge termination cleanly with no overcharge flag, and the protection circuit tripped at the expected low-voltage cutoff without any anomalous shutdowns.
• Cold-start satellite acquisition after power interruption: After fitting this cell, power the GPS-500 on outdoors with a clear sky view before your first drive. The unit performs a cold start after any full power removal — first satellite fix can take 5–10 minutes versus under a minute on a subsequent warm start.

GPS-500 shutting off without warning at apparent half charge

The GPS-500's fuel gauge is calibrated against the original cell's discharge curve. After fitting a new cell, the indicator can read inaccurately — the device hits its low-voltage cutoff threshold before the on-screen warning registers. This is a calibration lag, not a cell fault. Run two or three full charge-to-cutoff cycles and the gauge will track the new cell's curve. After recalibration, the warning should appear well before shutdown at roughly 3.4V.

Saved routes and POIs missing after battery swap

Some GPS-500 data — including recently entered destinations and certain route caches — is held in battery-backed RAM. A full power removal, as happens during a battery swap, can clear that volatile memory. Saved POIs stored to internal flash are typically retained, but active route data may not be. Before swapping the battery, export any routes you need to keep via the device's save or backup function, then re-import after the new cell is fitted and the unit has booted fully.