About this replacement
Epson WorkForce WF100 — 3.7V Li-ion Replacement Battery (D181A)
This 3.7V 2600mAh Li-ion cell replaces the OEM D181A battery in the Epson WorkForce WF100 portable inkjet printer and its variants. It fits the WF100, B581A, and PX-S05W. The connector and BMS handshake match the original, so the printer reads charge state correctly from the first boot.
- WF100, B581A, and PX-S05W compatibility: These three models share the same battery bay geometry, D181A connector pinout, and BMS communication protocol. One cell covers all three without modification.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on WF100 hardware. The BMS reported capacity accurately, and the printer completed multi-page print jobs without triggering a low-voltage cutoff.
- First-run charge tip for portable printers: Charge the battery fully before the first print run. The print head motor and heating element draw peak current simultaneously at startup. A partially charged cell can trip the BMS cutoff before the first page clears.
Why the WF100 drops its WiFi connection mid-print job
The WF100 runs its wireless radio and print motor from the same cell simultaneously. Under combined load, voltage sags enough that the radio module briefly loses power headroom and disconnects. This happens most often when battery charge is below 30% and the printer is handling a multi-page job. Keeping the cell above 40% charge during wireless print sessions prevents the sag from reaching the radio's dropout threshold.
Print quality dropping before the low-battery indicator appears
The heating element that drives ink transfer is voltage-sensitive. As the cell discharges, element temperature falls slightly below the target range before the printer's charge indicator catches up with real cell voltage. The result is lighter output or streaking that looks like a head problem but clears when the battery is recharged. If print quality degrades mid-job, stop and recharge — do not push the cell below 20% on print-heavy tasks. A full charge restores normal output immediately.