About this replacement
Zebra P4T / RP4T Series — 7.4V Li-ion Replacement Battery (CT18499-1)
This 7.4V, 5200mAh Li-ion battery replaces the OEM pack in the Zebra P4T, RP4T, and RP4 mobile thermal printers. It matches OEM part numbers CT18499-1, H16293-Li, HBP-420L, and ZB42L1-D. These printers run in retail stockrooms, logistics docks, and field service vehicles where a dead battery mid-shift is a real operational problem.
- P4T / RP4T / RP4 platform fit: All three models share the same battery bay, connector pinout, and BMS handshake protocol. The cell group voltage, protection circuit, and thermistor line are identical across the P4T and RP4 variants, so one battery covers the full platform.
- Bench tested on actual hardware: We cycled this pack on a P4T unit and confirmed the BMS completed its full charge profile without tripping the overcurrent threshold during paper feed motor start. Discharge curves stayed stable through repeated print bursts at rated load.
- First-use calibration for mobile printers: After installing, charge fully and print five test labels before deploying into a shift. The P4T's BMS needs a short active-load sequence to profile the new cell and set accurate fuel gauge readings — skipping this causes the low-battery indicator to fire early.
Why the P4T paper feed jams or stutters at partial charge
The P4T's paper feed motor is the highest current draw on the board. As cell voltage drops toward 6.8V under load, motor torque falls and feed pressure becomes inconsistent. This shows up as partial feeds, skipped labels, or a full jam where the printer stops mid-print. Keeping the pack above 7.0V resting voltage eliminates most feed-related faults on this platform.
Faded or uneven print density on a freshly installed battery
The thermal print head on the P4T regulates temperature by reading available voltage from the battery pack. A new cell that hasn't completed its first full charge cycle delivers slightly lower sustained voltage under print-head load, causing the head to run cooler than calibrated and producing faint or patchy output. This is not a head fault. Charge the pack to 100%, run five calibration prints, and print density normalises. If fading persists after that, check the thermal head contact pads for debris before replacing any components.