EXFO FIP-500 Fiber Inspection Replacement Battery 3.7V 5400mAh

EXFO FIP-500 Fiber Inspection Scope — 3.7V Li-Polymer Replacement Battery (880X279)

This 3.7V, 5400mAh Li-Polymer pack replaces the OEM battery in the EXFO FIP-500 fiber inspection scope and FIP-500-KIT variants (KIT-1, KIT-2, KIT-3). It matches the original 880X279 / E066 / GP-2301 part numbers and sits inside the same 81.10 × 31.10 × 17.20mm envelope. Capacity is 5400mAh (19.98Wh), identical to the factory specification.

• FIP-500 and KIT-1 / KIT-2 / KIT-3 compatibility: All four variants share the same internal battery bay dimensions, 3.7V power rail, and BMS communication protocol. The cell connector and protection circuit board are mechanically and electrically identical across the KIT configurations, so one pack covers every variant in the FIP-500 line.
• Bench tested on actual hardware: We powered an FIP-500 scope through the full boot sequence, probe illumination, and image-capture cycle. The BMS held the output rail steady under the LED driver load spike at probe activation and did not trip the overcurrent threshold during repeated captures.
• Post-install calibration cycle: After fitting this pack, run the FIP-500 through a full calibration sequence via the instrument menu before field deployment. The scope maps battery state during calibration — skipping this step causes premature low-battery alerts during the first inspection session, even when charge is adequate.

FIP-500 BMS lockout after the scope sat unused in a carry case for months

Li-Polymer cells self-discharge slowly during storage. If the FIP-500 sits dormant long enough, cell voltage can drop below the BMS recovery threshold — typically around 2.5V per cell — and the protection circuit latches off to prevent damage. At that point the scope will not power on and will not respond to the charger. Connect the scope to its OEM charger for at least 30 minutes without pressing the power button; the charger's trickle-charge stage brings cell voltage back above the BMS wake threshold, after which normal charging resumes. If the pack does not begin charging after 45 minutes on the trickle stage, the cells have discharged too deeply to recover and the pack should be replaced.

Scope display showing an unstable or jumping battery percentage after a fresh pack is fitted

The FIP-500 builds its charge-state map against the previous pack's discharge curve. When a new cell is installed, the voltage-threshold indicator has no calibration baseline for the new cells and reads the open-circuit voltage directly — which does not translate cleanly to a percentage until a full charge-discharge cycle reconditions the reference. Run the scope down to the low-battery warning, charge it fully to 4.2V, then repeat once more. After two complete cycles the percentage display stabilises and tracks accurately through the rest of the pack's service life.