About this replacement
Falk F3 / F4 / F6 — 3.7V Li-Polymer Replacement Battery (BLP5040021015004433)
This 3.7V, 1200mAh lithium-polymer cell replaces the factory battery in the Falk F3, F4, and F6 portable GPS navigators. All three units share the same battery bay dimensions and connector, making this a direct swap across the range. Capacity figures come from the product data — 1200mAh / 4.44Wh.
- F3, F4, and F6 compatibility: Falk used the same battery housing, connector pinout, and charge management circuit across this navigator family. The BMS handshake is identical on all three, so the cell charges and reports state-of-charge correctly without modification.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on the F-series platform. The BMS accepted charge from the OEM cradle, reached 4.2V at cutoff, and the device-side fuel gauge tracked depletion without triggering false low-battery warnings.
- First-fix cold start after fitting: After fitting this cell, power the unit on outdoors with a clear sky view and let it acquire a satellite fix before driving. A full power interruption forces a cold start — the GPS receiver clears its ephemeris cache and needs 5–10 minutes to rebuild satellite almanac data. Subsequent starts drop back to under a minute.
Falk F-series shutting off before the battery indicator hits zero
The F-series fuel gauge is calibrated against the original cell's discharge curve. A new cell with a slightly different internal resistance profile causes the gauge to read optimistically — the device hits the hardware voltage cutoff at 3.0V while the screen still shows one bar. The fix is to run two or three full discharge-to-cutoff cycles so the device recalibrates its threshold mapping. After that, the shutdown warning and actual cutoff align correctly.
Saved routes and POIs missing after battery replacement
The Falk F-series stores some navigation data — including recent routes and custom POIs — in battery-backed RAM rather than flash memory. When the cell is fully removed, that RAM loses power and the contents are cleared. Before swapping the battery, export any custom routes via the PC sync tool or note waypoints manually. Once the new cell is fitted and the device boots, re-import the saved route file to restore navigation data.