About this replacement
EXFO FTB-150 / FTB-200 — 14.4V Li-ion Replacement Battery (XW-EX002)
This is a 14.4V 5200mAh (74.88Wh) lithium-ion battery for the EXFO FTB-150 and FTB-200 portable fiber optic test platforms. It replaces OEM part numbers XW-EX002, XW-EX006, L08D185A, and L08D185UG. Telecommunications technicians use it to maintain continuous OTDR and loss-measurement sessions when AC charging is not available in the field.
- FTB-150 and FTB-200 compatibility: Both platforms run the same 14.4V battery rail and use the same connector and BMS handshake protocol. One pack covers both units, which matters for teams running mixed fleets on the same job site.
- Bench tested on actual hardware: We ran this pack through the FTB-150 power-on sequence, including full optical module initialisation. The BMS handled the probe power-up current spike without tripping, and voltage held within spec across sustained OTDR acquisition cycles.
- Post-install calibration cycle: After fitting this battery, run a full calibration cycle through the FTB instrument menu before field deployment. The instrument maps battery state during calibration — skipping this step causes the low-battery indicator to trigger prematurely during your first measurement session.
BMS cutoff when the FTB-150 optical module powers up
The FTB-150 draws a sharp current spike the moment it powers up the optical test module. On aged or deeply discharged cells, internal resistance is high enough that this spike causes a brief but significant voltage sag at the BMS. The BMS reads that sag as an unsafe condition and cuts output — the unit shuts off immediately after the splash screen. This pack's cells are sized to keep that sag below the 11.5V BMS cutoff threshold during cold initialisation.
FTB-150 showing erratic battery percentage after a pack swap
After fitting a new pack, the FTB-150 percentage display often reads inaccurately for the first one or two sessions. The instrument's voltage-threshold indicator is still calibrated to the discharge curve of the old, degraded cells. The fix is to run the pack down to the low-battery warning through normal use, then charge it fully without interruption — one complete cycle resets the reference point. After that cycle, the percentage display tracks accurately against the new cells.