Garmin Nuvi 300 Replacement Battery 3.7V 1250mAh

Garmin Nuvi 300 Series — 3.7V Li-Polymer Replacement Battery (361-00019-02)

This 3.7V, 1250mAh lithium-polymer cell replaces the original power source in the Garmin Nuvi 300, 300T, 310, and 310D portable GPS navigators, along with six additional Nuvi models. It matches the OEM voltage rail and physical footprint at 37 × 60 × 5.20mm. Capacity is sourced from the product data at 4.63Wh — no inflated figures.

• Nuvi 300 series compatibility: These models share the same internal battery bay dimensions, 3.7V single-cell architecture, and flat flex connector orientation. The BMS handshake on each unit reads cell voltage directly — no proprietary authentication chip to trip on a third-party cell.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a Nuvi 310. The BMS accepted the cell without fault codes, held charge to rated capacity, and cut off cleanly at the low-voltage threshold without premature shutdown.
• First-use satellite acquisition: After fitting this cell, power the unit on outdoors and let it acquire a satellite fix before driving. Any full power interruption triggers a cold start — first fix takes 5–10 minutes outdoors versus under a minute on subsequent warm starts.

GPS accuracy reduced at low battery on the Nuvi 300 series

When cell voltage drops toward the lower threshold, the Nuvi 300 series reduces receiver sensitivity to extend operating time. The GPS antenna draws continuous power for signal processing, and the unit scales that draw back as voltage sags. You may notice position drift or slower route recalculation before the low-battery indicator even appears on screen. Keeping the cell above 3.5V under load maintains full receiver performance.

Nuvi 300 shutting off without warning before the battery indicator reads empty

The battery gauge on the Nuvi 300 is calibrated against the original cell's discharge curve. After years of use, or when a new cell with slightly different internal resistance is fitted, the gauge loses accuracy. The unit hits its hardware cutoff voltage while the display still shows partial charge. Fix this by running two full charge and discharge cycles — the firmware re-maps the discharge curve against real cell behaviour and the indicator aligns correctly by the third cycle.