Pentax PocketJet II 14.4V Replacement Battery PT-1501A

Pentax PocketJet II / PocketJet 3 Series — 14.4V Ni-MH Replacement Battery (PT-1501A)

This is a 14.4V Ni-MH replacement battery rated at 360mAh (5.18Wh) for the Pentax PocketJet II and PocketJet 3 portable printers, including the PJ200. It replaces OEM part numbers PT-1501A and 205526. If the original cell no longer holds a charge or the printer dies partway through a job, this is the swap.

• PocketJet II, PocketJet 3, and PJ200 fit: These models share the same 14.4V battery bay, connector pinout, and BMS handshake protocol. One replacement covers the entire platform — the voltage rail and physical form factor are identical across the group.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on a PocketJet 3 unit. The BMS accepted the new cell without fault codes, thermal regulation kicked in at expected draw levels, and the print motor received consistent current across the discharge curve.
• First-use print sequence: After installing, charge the battery fully, then run five consecutive test prints before field deployment. The paper feed motor draws a brief high-current pulse on each page start — this sequence confirms the BMS has established a correct current profile for the new cell and prevents false low-battery shutdowns mid-job.

Voltage drop under thermal head load in the PocketJet series

The PocketJet's thermal print head draws a concentrated burst of current to heat the element for each dot row. At low or degraded battery charge, this burst causes a momentary voltage sag that the BMS reads as an undervoltage event. The printer may pause, reset, or cut out entirely mid-page. A fully charged, fresh Ni-MH cell at 14.4V nominal holds the voltage rail stable enough to prevent this. If the printer resumes normally after reconnecting to power, the battery — not the head or driver board — is the cause.

Printer powers on but paper feeds and stops after one line

This is a motor torque failure, not a paper jam. The feed motor needs sufficient voltage to maintain grip pressure through the full page length. When cell voltage sags below roughly 12V under load, grip torque drops and the paper stalls. The printer interprets this as a feed error and stops. Charge the battery to full, confirm the indicator shows 100%, and retry — if the feed still stalls, check that the replacement cell is seated flush with no connector gap.