About this replacement
NavGear StreetMate GP-43 — 3.7V Li-Polymer Replacement Battery (W423759)
This 3.7V 1200mAh lithium-polymer cell is a direct replacement for the NavGear StreetMate GP-43 portable GPS navigator. It matches the original W423759 specification at 4.44Wh and fits the same 52.20 × 41.91 × 6.14mm footprint. Fits the StreetMate GP-43 only — check your part number before ordering.
- StreetMate GP-43 fitment: The GP-43 uses a single-cell Li-Po pack with a low-current protection circuit matched to the navigator's charging IC. This cell carries the same W423759 part number and connector orientation, so the BMS handshake between the pack and the device's charge controller completes without fault codes.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the GP-43 platform. The onboard BMS reached full-charge cutoff cleanly at 4.2V per cell and low-voltage cutoff triggered correctly before the navigator shut down, protecting the cell from over-discharge damage.
- First-use satellite acquisition: After fitting this cell, power the GP-43 fully on outdoors and let it acquire a satellite fix before driving. The navigator performs a cold start after any full power interruption — first fix typically takes 5–10 minutes outdoors. Subsequent warm starts drop to under a minute once almanac data is cached.
GPS accuracy dropping at low battery on the GP-43
Some portable GPS units reduce receiver sensitivity as battery voltage sags toward the low-voltage cutoff threshold. On the GP-43, this can cause position drift or missed route recalculations before the battery indicator shows critical. The root cause is the receiver drawing slightly less power to compensate for reduced supply headroom. Keep the cell above 3.6V during active navigation to maintain full receiver sensitivity.
GP-43 shuts off without warning before the battery indicator reaches empty
This happens when a degraded original cell's actual capacity no longer matches the fuel gauge's calibration — the navigator's voltage-threshold model was built around a healthy cell. The device hits the hardware cutoff voltage before the on-screen indicator has stepped down to the final bar. After fitting a fresh W423759 cell, run two full charge-discharge cycles so the GP-43 can recalibrate its threshold model. The indicator and actual shutoff point will align once the device has sampled the new cell's discharge curve.