Intermec PB21 Replacement Battery 7.4V 3400mAh Li-ion

Intermec PB21 / PB22 / PB31 / PB32 — 7.4V Li-ion Replacement Battery (318-030-001)

This 7.4V 3400mAh Li-ion battery replaces OEM part numbers 318-030-001, 318-030-003, and AB27 in the Intermec PB21, PB22, PB31, and PB32 mobile printers. These are field-use receipt and label printers common in logistics, retail, and service operations where mains power is not available. Capacity is 3400mAh (25.16Wh) — matching OEM specification from product data.

• PB21 / PB22 / PB31 / PB32 platform compatibility: All four models share the same 7.4V battery rail, physical form factor, and BMS handshake protocol. The connector pinout and communication lines are identical across the series, so one cell fits all four without modification.
• Bench tested on actual hardware: We ran this battery through charge cycles on the PB21 and PB31. The BMS accepted charge correctly from Intermec dock chargers, reported state-of-charge accurately to the printer firmware, and held voltage stable across thermal head activation cycles without triggering low-voltage cutoff prematurely.
• First-use print sequence: After installing, charge fully, then print five consecutive test labels before deploying in the field. The paper feed motor draws a brief current spike on each job — running this sequence lets the BMS log the current profile and calibrate charge-level reporting accurately for that specific unit.

Intermec PB-series Bluetooth dropping mid-print job

The PB21 and PB31 run their Bluetooth radio and thermal print head from the same 7.4V supply. When battery voltage sags below roughly 6.8V under combined load, the radio loses enough power to drop its connection before the printer firmware triggers a low-battery shutdown. The print job stalls, the app loses pairing, and the printer appears to have crashed. This is a voltage-sag event, not a radio fault. Keeping the battery above 50% charge during heavy print runs prevents the sag from reaching that threshold.

Faded or uneven print after fitting a replacement battery

The thermal print head in the PB-series requires a stable, consistent voltage to maintain head temperature across a full label or receipt. If voltage delivery is inconsistent — common with a degraded or incorrectly initialised battery — head temperature fluctuates mid-print, producing faded bands or uneven density. This is not a head fault. Run the five-receipt calibration sequence after first charge, then check that the printer firmware shows battery status as "normal" rather than "low" or "unknown." If the print firmware still reports abnormal status after calibration, discharge to 20% and perform one full charge cycle before re-testing.