About this replacement
Zebra QLN220 / QLN320 Series — 7.4V Li-ion Replacement Battery (AT16004)
This 7.4V 3400mAh Li-ion battery replaces the AT16004 and fits the Zebra QLN220, QLN220HC, QLN320, and QLN320HC mobile thermal printers. These are field-use receipt and label printers common in retail, warehousing, and logistics. Swap this in when the original battery no longer holds a working charge through a shift.
- QLN220 and QLN320 shared battery platform: Both the standard and HC (healthcare) variants of the QLN220 and QLN320 run the same 7.4V battery rail with identical connector pinout and BMS handshake. One cell SKU covers all four printer variants because the BMS negotiation protocol and charge termination voltage are the same across the platform.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a QLN220 unit. The BMS accepted the charge handshake immediately, reached full charge termination at the correct voltage ceiling, and the printer's battery indicator reported state-of-charge accurately within two cycles.
- First-deploy print sequence: After installing this battery, charge it fully, then print five test labels before sending the unit into rotation. The paper feed motor draws a brief high-current pulse on each feed cycle — running those test prints lets the BMS log an accurate current profile for the new cell and prevents false low-battery cutoffs during the first day of use.
Why the QLN220 thermal head prints faded lines on a low or aging battery
The QLN220's thermal print head requires a stable voltage supply to hold the correct head temperature during each dot-fire cycle. When battery voltage sags under load — either from a depleted charge or degraded cells — head temperature drops mid-line, producing faded or uneven print density. This is not a head fault or media issue; it is a voltage delivery problem. Replacing the battery and charging fully before printing will restore consistent dot density across the label width.
Bluetooth drops mid-print job on the QLN220
The QLN220's Bluetooth radio and paper feed motor compete for current at the moment a print job starts. At low battery charge, the motor's start-up draw pulls voltage down far enough to cause the radio to reset, which drops the Bluetooth connection and halts the job. The printer logs this as a communication error, not a battery fault, which makes it easy to misdiagnose. Keep the battery above 40% charge during active print sessions — if the drops persist on a fresh battery, check that the host device's Bluetooth timeout setting is not shorter than the job transfer time.