Sony NV-U53G GPS Navigator Replacement Battery 3.7V 800mAh

Sony NV-U53G / NV-U82 Series — 3.7V Li-ion Replacement Battery (3-281-790-02)

This is a 3.7V, 800mAh Li-ion cell that replaces part number 3-281-790-02 in Sony's NV-U portable GPS navigator range. It fits the NV-U53G, NV-U73T, NV-U82, NV-U83, and three additional models in the same series. Dimensions are 35.41 × 32.59 × 8.25mm — measure your original before fitting if you are unsure which variant you have.

• NV-U53G / NV-U82 series compatibility: These models share the same 3.7V single-cell architecture, connector pinout, and BMS handshake protocol — one cell covers the full lineup without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the NV-U82 platform. The onboard BMS accepted the cell without fault codes, and charge termination fired correctly at 4.2V.
• First satellite fix after fitting: After any full power interruption the GPS module loses its ephemeris data and performs a cold start. Power the unit on outdoors with a clear sky view and leave it for 5–10 minutes before driving — subsequent warm starts will lock in under a minute.

GPS accuracy dropping as battery level falls

Some Sony NV-U units reduce RF receiver sensitivity at low battery to cut current draw. This shows up as position drift or the blue dot jumping between streets even on a familiar route. It is not a GPS signal problem — it is a power management response. Keep the battery above 20% on long drives, or plug into car power via the vehicle adapter to hold the receiver at full sensitivity.

Unit shuts off without a low-battery warning

After a battery swap the fuel gauge IC has no charge history to reference, so its voltage-to-capacity curve is uncalibrated. The unit reads remaining charge as higher than it actually is until the cell has been through at least one full cycle. Run the battery from a full charge down to automatic shut-off, then charge uninterrupted to 100% — after that cycle the warning threshold aligns with the actual cutoff voltage near 3.0V.