JDSU LI202S-6600 Replacement Battery 10.8V 6600mAh

JDSU LI202S-6600 — 10.8V Li-ion Replacement Battery (LI202S-6600)

This 10.8V, 6600mAh Li-ion battery replaces OEM part numbers LI202S-6600 and LI202S66A in JDSU portable optical and network test equipment. It delivers 71.28Wh of capacity for extended field sessions testing fiber optic and copper networks. Telecommunications technicians use this cell to keep diagnostic gear running through full site visits without access to mains power.

• JDSU field test platform fit: JDSU portable test units share a common 10.8V three-cell Li-ion architecture with a BMS that handshakes on connector pinout and voltage rail. Both LI202S-6600 and LI202S66A OEM references map to the same physical pack, so either part number confirms this cell fits.
• Bench tested on actual hardware: We cycled this cell through charge, full discharge, and BMS fault-check sequences. The protection circuit responded correctly to over-voltage and under-voltage thresholds, and charge acceptance held at rated capacity across test runs.
• First-cycle calibration on JDSU gear: After fitting this cell, run the unit on battery until the low-power shutdown triggers — do not interrupt. Then charge uninterrupted to 100%. JDSU test equipment uses a fuel gauge IC that reads the old cell's EEPROM data; this full discharge-charge cycle forces the IC to re-learn the new cell's actual capacity curve and clears the inaccurate state-of-charge readings that appear after a swap.

Why JDSU test units show "Battery Not Detected" or 0% after a cell swap

JDSU portable testers store battery identity data in EEPROM on the BMS board. When the old pack is removed, the fuel gauge IC loses its reference and the unit can display 0%, "unknown battery," or a health warning even with a fully charged replacement installed. This is a firmware-side artefact, not a fault with the new cell. Running one full discharge-to-shutdown followed by an uninterrupted charge to 100% rewrites the fuel gauge's learned values against the new cell chemistry and clears the warning.

Unit shuts down mid-test with charge indicator still showing 25–35%

JDSU test equipment draws sharp current spikes during active optical signal generation and high-speed copper line analysis. An aged or deeply discharged cell cannot sustain voltage under that load and hits the BMS under-voltage cutoff while the fuel gauge still reads a significant percentage — this is a voltage-cliff failure, not a capacity display error. The fix is a full calibration cycle: discharge to hibernate cutoff, then charge to 100% without interruption. If the problem persists after two calibration cycles, check that the cell resting voltage is at or above 11.1V before the session begins.