About this replacement
Falk M2 / M4 / M6 / M8 — 3.7V Li-Polymer Replacement Battery (57181740068)
This 3.7V, 750mAh Li-Polymer cell replaces the original battery in the Falk M2, M4, M6, and M8 portable GPS navigators. It restores power to the device's display, processor, and GPS receiver. Capacity figures are taken directly from product data — 750mAh / 2.78Wh.
- M2 / M4 / M6 / M8 platform fit: These four Falk navigator models share the same battery bay dimensions, connector pinout, and 3.7V supply rail. One cell covers the full range without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench. The BMS held cutoff voltage correctly at both ends — no undervoltage dropout and no overcharge condition observed during testing.
- First-fix cold start after swap: After fitting this cell, power the unit on outdoors before driving. The GPS performs a full cold start after any complete power interruption — first satellite fix can take 5–10 minutes. Subsequent warm starts drop to under a minute once almanac data is re-cached.
GPS accuracy reduced as the Falk M2 battery level drops
At low charge, some Falk navigators reduce power to the GPS receiver module to protect the remaining cell voltage. This lowers receiver sensitivity and can cause position drift or signal loss in areas with partial sky cover. The symptom often appears before the low-battery icon shows, because the receiver steps down before the display threshold is hit. Keeping the cell above 3.5V during active navigation avoids the sensitivity reduction entirely.
Falk navigator shuts off without warning during a route
After a new cell is fitted, the fuel gauge IC has no calibration history for the replacement cell's actual discharge curve. The device's low-battery warning threshold can trigger too late — or not at all — causing an abrupt shutdown. Run two full charge and discharge cycles to let the gauge recalibrate against the new cell. After that, the indicator should align with actual remaining charge and cut off around 3.4V as expected.