Zebra QL420 Replacement Battery 7.4V 6800mAh AT16293-1

Zebra QL420 / QL420+ Series — 7.4V Li-ion Replacement Battery (AT16293-1)

This 7.4V Li-ion battery carries 6800mAh (50.32Wh) and fits the Zebra QL420, QL420+, and QL420 Plus mobile thermal printers. These units run on-site barcode and label printing across warehouse floors, delivery routes, and retail environments. This pack slots directly into the battery bay and communicates with the printer's BMS using the original connector and cell profile.

• QL420 and QL420+ compatibility: Both the QL420 and QL420+ share the same 7.4V power rail, physical bay dimensions, and BMS handshake protocol — AT16293-1 is the correct part number for both variants. The connector pinout is identical across the series, so one SKU covers all three models.
• Bench tested on actual hardware: We ran this pack on a QL420 unit and confirmed the BMS handshake completed without fault flags. The printer accepted a charge cycle, reached full voltage, and the paper feed motor drew current within the expected profile throughout the print sequence.
• First-run calibration after install: After fitting this battery, charge it fully, then print five test labels before deploying the unit. The paper feed motor's current draw during that sequence lets the BMS lock onto the correct load profile for the new cells — skipping this step can cause the BMS to report a false low-battery warning under motor load.

Why the QL420 stops printing after sitting unused for weeks

Li-ion cells self-discharge at roughly 2–3% per month under normal storage, but the QL420's BMS applies a hard cutoff below approximately 6.0V to protect cell chemistry. If the printer sat long enough to drop below that threshold, the BMS locks output entirely — the printer appears dead even though the battery still holds a partial charge. Connecting the printer to the charger for at least 30 minutes brings the pack above the recovery voltage and allows the BMS to re-enable output. Once the display shows a charge level, a normal full charge cycle restores the pack to working state.

Bluetooth or Wi-Fi dropping mid-print job on the QL420

The QL420's radio module and thermal print head draw current simultaneously during a wireless print job, and voltage sag at low state-of-charge can pull the supply rail below the radio's minimum operating threshold. The printer doesn't report a connection error — it just drops the link and the job stalls. This is not a pairing issue or a firmware fault; it is a voltage floor problem. Charge the battery to at least 7.2V before starting large batch print jobs, and the radio will maintain a stable connection throughout.