About this replacement
EXFO EX1 — 3.7V Li-ion Replacement Battery (GP-2268)
This 3.7V 3400mAh Li-ion battery replaces the GP-2268 pack in the EXFO EX1 portable fiber optic test instrument. It fits the EX1 directly, restoring field power for loss measurement, cable inspection, and network diagnostics. Voltage and capacity match the OEM specification exactly.
- EX1 platform fit: The EX1 uses a single-cell 3.7V architecture with a BMS that authenticates voltage thresholds and monitors cell temperature during optical module power-up. This pack matches those thresholds, so the instrument does not flag a battery fault on boot or during probe initialisation.
- Bench tested on actual hardware: We cycled this pack through EX1 power-on, optical source activation, and sustained loss-measurement logging. The BMS held stable through the initialisation current spike and did not trip during continuous instrument load.
- Post-install calibration cycle: After fitting this pack, run a full calibration cycle from the EX1 instrument menu before heading into the field. The EX1 maps battery state during calibration — skipping this step causes the low-battery indicator to fire early on the first measurement session, even when the cell is fully charged.
BMS cutoff when the EX1 optical module powers up
The EX1 draws a short current spike the moment the optical source initialises. A degraded or deeply discharged cell cannot sustain voltage through that spike, and the BMS trips as a protection response. The instrument shuts off instantly — it does not show a low-battery warning first. Charge the pack to full before the first use and confirm resting voltage is at or above 3.7V before inserting it into the unit.
EX1 showing inconsistent battery percentage after a fresh install
The EX1 fuel gauge recalibrates to the new cell's voltage curve over the first charge-discharge cycle. Until that cycle completes, the percentage display may jump or read higher than expected at reboot. This is not a fault with the pack — the instrument is recalculating its threshold map against the new cell. Run one full charge to 4.2V, then discharge through a normal measurement session, and the indicator stabilises.