NavGear Streetmate GP-43 Replacement Battery 3.7V 1250mAh

NavGear Streetmate GP-43 — 3.7V Li-Polymer Replacement Battery

This is a 3.7V 1250mAh (4.63Wh) lithium-polymer cell for the NavGear Streetmate GP-43 portable GPS navigator. It fits directly into the GP-43 and restores power to the navigation display, GPS receiver, and onboard memory. Dimensions are 37.00 × 60.00 × 5.20mm — verify against your existing cell before ordering.

• GP-43 fit notes: The Streetmate GP-43 uses a slim Li-Polymer pouch cell at this exact voltage and footprint. The 3.7V nominal rail matches the device's power circuit, which the internal BMS monitors for under-voltage cutoff protection.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench, confirmed BMS cutoff engaged correctly at low voltage, and verified the charge termination voltage held within spec under a standard 5V USB input.
• First outdoor power-on after fitting: After fitting this cell, power the GP-43 fully on outdoors and let it acquire a satellite fix before driving. GPS units perform a cold start after any full power removal — first fix can take 5–10 minutes. Subsequent warm starts drop to under a minute once the almanac is restored.

GPS accuracy reduced at low battery on the Streetmate GP-43

The GP-43's GPS receiver draws continuous power to maintain satellite signal lock. At low cell voltage, some GPS units reduce receiver sensitivity to extend operation — this shows up as position drift or a weaker signal bar count. The root cause is the cell voltage dropping below roughly 3.5V, where the device begins throttling power to non-essential circuits. Keeping the cell above 3.6V during active navigation maintains full receiver sensitivity.

GP-43 shuts off without any low-battery warning

This happens when the battery indicator is uncalibrated to the new cell's discharge curve. The original firmware maps the fuel gauge to the old cell's internal resistance profile — a fresh cell discharges differently, so the visual warning threshold triggers late or not at all. The BMS hard cutoff then fires at the under-voltage limit before the on-screen warning appears. Run two full charge-discharge cycles to allow the gauge to recalibrate, then check that the low-battery icon appears before the device shuts off at approximately 3.4V.