Garmin Nuvi 1400 Replacement Battery ED38BD4251U20 3.7V

Garmin Nuvi 1400 / 1450 / 1490T — 3.7V Li-Polymer Replacement Battery (ED38BD4251U20)

This 3.7V, 1250mAh Li-Polymer cell replaces the original battery in the Garmin Nuvi 1400, 1450, 1450T, and 1490T portable GPS navigators. It matches the OEM part number ED38BD4251U20 and fits the same footprint at 59 x 37 x 5mm. Install it when the unit no longer holds charge away from the car charger.

• Nuvi 1400 series compatibility: The 1400, 1450, 1450T, and 1490T share the same battery bay dimensions, connector pinout, and 3.7V power rail. One cell covers all four models without modification.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the Nuvi platform. The BMS held the charge curve within spec and tripped the protection circuit correctly at the low-voltage threshold — no unexpected cutoffs during GPS-active sessions.
• First fix after battery swap: After fitting this cell, power the Nuvi on outdoors and let it acquire a satellite fix before driving. A full power interruption forces a cold start — first fix takes 5–10 minutes. Subsequent warm starts drop to under a minute once almanac data is cached.

GPS accuracy dropping at low battery on the Nuvi 1400

Some Nuvi units reduce GPS receiver sensitivity when battery voltage falls below roughly 3.5V. This is a firmware-level power-saving measure — the receiver draws less current, but satellite signal acquisition weakens as a result. Position drift and recalculation errors increase. Keeping the cell charged above the low-battery threshold prevents this behaviour entirely.

Nuvi 1400 shutting off without a low-battery warning

The battery indicator on the Nuvi 1400 reads state-of-charge from a voltage curve calibrated to the original cell. After a battery swap, that curve is uncalibrated — the device can show two bars and cut off seconds later. The BMS protection circuit trips at the true low-voltage floor before the display catches up. To recalibrate, run two full charge-to-discharge cycles so the firmware can map the new cell's voltage curve. The indicator stabilises after the second full cycle.