Epson L-500V Replacement Battery 3.7V 1230mAh Li-ion

Epson L-500V — 3.7V Li-ion Replacement Battery (B31B173003CU)

This 3.7V Li-ion cell replaces the original battery in the Epson L-500V mobile printer. It carries 1230mAh (4.55Wh) — matching the OEM pack's voltage rail and connector footprint. If your L-500V stops printing mid-job or refuses to power on away from a desk, this is the direct swap.

• L-500V platform fit: The L-500V runs a single-cell 3.7V architecture with a compact PCB footprint. Replacement cells must match the BMS handshake profile and the physical 38.32 × 38.11 × 9.41mm envelope — oversized cells will not seat correctly in the battery bay.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the L-500V platform. The BMS accepted the cell without fault codes, held voltage above 3.5V through mid-capacity, and cut off cleanly at the low-voltage threshold without tripping a hard fault.
• Print-head priming draw: The L-500V draws a current spike during ink priming on startup. Run one full charge before the first print job — the BMS needs a baseline calibration cycle to report remaining capacity accurately during high-draw priming sequences.

Why the L-500V BMS rejects a new cell on first install

The L-500V's battery management system checks cell voltage at the point of contact. A new Li-ion cell shipped in storage mode may sit below 3.0V, which the BMS reads as a damaged or deeply discharged pack and blocks the power-on sequence. Connecting the printer to USB power or the OEM charger for 15–20 minutes before pressing power gives the BMS enough charge to recognise the cell as valid. Once voltage clears approximately 3.2V, normal operation resumes.

Battery percentage dropping suddenly then recovering mid-print

This happens when the L-500V's fuel gauge is still mapped to the discharge curve of the old, degraded cell. A new cell has a flatter mid-range discharge curve than a worn pack, so the indicator algorithm misreads the voltage and reports a sharp drop before correcting itself. Run two full charge-discharge cycles through the printer and the gauge recalibrates to the new cell's curve. After that, the percentage readout tracks steadily from full down through the actual low-voltage cutoff near 3.0V.