About this replacement
Geo-Fennel Rotationslaser FL 200A — 4.8V Ni-MH Replacement Battery (290000-14)
This is a 4.8V, 1800mAh Ni-MH replacement battery for the Geo-Fennel Rotationslaser FL 200A, Rotationslaser FL 20, and Linienlaser FLG 40-Green. It replaces OEM part number 290000-14 and fits the same battery bay without modification. Capacity is 1800mAh — matching the original pack specification.
- FL 200A, FL 20, and FLG 40-Green compatibility: These three instruments share the same 4.8V battery rail, physical form factor, and BMS handshake protocol. The same pack pulls from an identical connector and voltage threshold across all three, which is why one replacement covers the full group.
- Bench tested on actual hardware: We ran this pack through charge and discharge cycles on the FL 200A platform. The BMS accepted charge without fault, and the instrument's low-battery threshold triggered at the correct voltage point — no early cutoff, no false low-battery alerts during the test.
- Post-installation calibration cycle: After fitting this pack, run a full calibration cycle through the instrument menu before taking it to site. The FL 200A maps battery state during calibration. Skip this step and the instrument will throw premature low-battery warnings on the first field session, even with a fully charged pack.
BMS lockout after the FL 200A sat unused in a carry case for months
Ni-MH cells self-discharge faster than Li-ion. If this instrument sat packed away for several months, the pack voltage can drop below the BMS recovery threshold. At that point, the BMS enters a protection state and the instrument appears completely dead — no response at power-on, no charge indication. Place the pack on charge for at least 90 minutes before attempting to power the instrument. Most chargers will recover a depleted Ni-MH pack as long as the cell voltage hasn't collapsed below approximately 0.9V per cell.
FL 200A shuts down mid-rotation during a leveling session
The rotating motor mechanism draws a sustained current load that spikes briefly each time the instrument adjusts its self-leveling pendulum. On an aged or partially discharged pack, this spike is enough to pull cell voltage below the BMS cutoff threshold, causing a mid-session shutdown even though the display showed sufficient charge seconds earlier. This is voltage sag under load — not a faulty instrument. Fit a freshly charged pack and confirm resting voltage is at or above 5.4V before starting a session. If shutdowns recur on a new pack, check that the charger is delivering a full charge cycle rather than terminating early.