About this replacement
EXFO PPM-350D PON Power Meter — 3.7V Li-Polymer Replacement Battery (GP-2277)
This is a 3.7V, 2400mAh Li-Polymer replacement battery for the EXFO PPM-350D and PPM-350D PON Power Meter. It powers the meter's display, optical input circuitry, and measurement processing in the field. The OEM part numbers this cell replaces are GP-2277 and U832948-2P-R.
- PPM-350D and PPM-350D PON compatibility: Both variants use the same 3.7V cell and share an identical battery bay connector and BMS handshake protocol — the PON model adds a second optical port but draws from the same voltage rail, so one pack covers both units.
- Bench tested on actual hardware: We ran this pack through full charge and discharge cycles on the bench, verified BMS communication at startup, and confirmed the cell holds voltage under the sustained low-current draw the PPM-350D's measurement circuitry applies during active testing sessions.
- Post-installation calibration on the PPM-350D: After fitting a new pack, run a full calibration cycle through the instrument menu before field deployment. The meter maps battery state during calibration — skipping this step causes premature low-battery warnings to appear during your first measurement session even when the cell is near full charge.
BMS lockout after the PPM-350D sat unused in a carry case for months
Li-Polymer cells self-discharge slowly in storage. If the PPM-350D sat unused long enough, the cell voltage can drop below the BMS protection threshold — typically around 2.5V — and the pack enters a locked state. In this state the meter will not power on and the charger may show no activity. To recover the pack, connect the meter to its charger and leave it for 30–60 minutes without attempting to power it on; the charger's trickle stage should bring the cell back above the 2.9V threshold where the BMS re-enables discharge. If the charger shows no response after 60 minutes, the cell has dropped below recovery voltage and the pack needs replacement.
Meter shuts down mid-measurement with no low-battery warning
This happens when the BMS detects a brief voltage sag that crosses its undervoltage cutoff — not a capacity problem but a load-spike issue. On the PPM-350D, the optical frontend and display draw a combined pulse of current at certain measurement intervals, and an aged or cold cell can sag enough at that moment to trip the protection circuit. The meter powers off instantly with no warning because the BMS cuts before the fuel gauge has time to update the display. Check the cell voltage at rest with a multimeter: if it reads above 3.6V but the meter still cuts out under load, the cell's internal resistance has increased and replacement is the correct fix.