Zebra WT41N0 Replacement Battery 3.7V 3400mAh Li-ion

Zebra WT41N0 / WT4090 / WT4000 — 3.7V Li-ion Replacement Battery

This 3.7V 3400mAh Li-ion battery replaces the original pack in the Zebra WT41N0, WT4090, and WT4000 wearable mobile computers. These devices run barcode scanning and data collection workflows in warehouse, retail, and field service environments. Voltage and capacity match the original spec — 3.7V, 3400mAh (12.58Wh).

• WT41N0 / WT4090 / WT4000 compatibility: All three models share the same battery bay geometry, contact pinout, and BMS handshake protocol. A single cell chemistry and connector spec covers the full platform, so one replacement works across all three.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on a WT41N0 unit. The BMS accepted the cell, reported state-of-charge correctly to the device OS, and held voltage through both idle and active scan bursts without tripping a protection cutoff.
• First-shift preparation: After installing this pack, seat the scanner in its charging cradle and run a full charge cycle before the first pick-and-pack shift. Scan trigger inrush current is highest when the cell is near minimum charge — starting the shift on a full pack prevents false BMS trips on heavy-scan lines.

Cradle showing a charging error on a new pack

Charging docks on the WT-series use spring-loaded contacts that oxidise with repeated insertions. When contact resistance climbs above the dock's threshold, it flags a charging fault even with a good cell installed. Wipe the gold contacts on both the battery and the cradle with a dry lint-free cloth, then reseat the pack firmly until the dock clicks. If the error clears within 30 seconds, the contacts were the cause — not the cell.

Scanner losing wireless connection during rapid scan bursts

The WT41N0 draws current from two sources simultaneously during a scan burst: the imager or laser module and the 802.11 radio. When both pull at once, a degraded or partially charged cell can sag below the radio's minimum operating voltage, dropping the wireless link mid-scan. This shows up as intermittent disconnects timed exactly to rapid scanning — not random dropouts. Charge the pack fully before the shift; a cell at or above 4.1V handles the combined draw without sagging.