Garmin Nuvi 770 Replacement Battery 3.7V 1250mAh

Garmin Nuvi 770 / 770T — 3.7V Li-Polymer Replacement Battery (010-00657-06)

This 3.7V 1250mAh lithium-polymer cell replaces the factory battery in the Garmin Nuvi 770 and Nuvi 770T portable GPS navigators. It matches the OEM part number 010-00657-06 and fits the 60.80 × 36.60 × 5.30mm cavity. Capacity is 4.63Wh — identical to the original specification.

• Nuvi 770 and 770T compatibility: Both models run the same 3.7V single-cell architecture with the same connector pinout and BMS handshake. One cell covers both variants without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a Nuvi 770 unit. The BMS accepted charge from the OEM cradle without fault flags, and the protection circuit tripped correctly at the low-voltage cutoff threshold.
• Cold-start satellite acquisition: After fitting this cell, power the unit on outdoors before your first drive. A full power interruption forces a cold start — the GPS receiver needs 5–10 minutes to re-acquire satellite almanac data. Subsequent starts return to normal warm-start speed once the almanac is cached.

GPS accuracy reduced when the Nuvi 770 battery level drops below 20%

The Nuvi 770's receiver can pull back sensitivity as the cell voltage sags toward the low-voltage threshold. At reduced receiver sensitivity, the unit holds lock on fewer satellites, which widens the position error circle. This shows up as map position jumping between streets or routing decisions that seem off. Keeping the cell above 3.6V under load maintains full receiver performance.

Nuvi 770 shuts off without warning instead of showing a low-battery alert

The on-screen battery indicator on the Nuvi 770 is calibrated to the original cell's discharge curve. A new cell has a slightly different curve until it completes two or three full charge cycles. During that break-in period, the indicator can read 20–30% and then the unit shuts off immediately when cell voltage hits the BMS cutoff at approximately 3.0V. Run two complete charge-discharge cycles to let the indicator recalibrate against the new cell's actual curve.