Zebra TC21 Replacement Battery BT-000409 3.8V 3050mAh

Zebra TC21 / TC26 Series — 3.8V Li-ion Replacement Battery (BT-000409)

This 3.8V, 3050mAh Li-ion battery replaces the original pack in the Zebra TC21 and TC26 series handheld mobile computers. It covers TC21, TC26, TC26AK, TC210, and related variants using the BT-000409 battery platform. Capacity figure comes from product data — 11.59Wh total energy.

• TC21 / TC26 platform fit: These models share a common battery bay geometry, connector pinout, and BMS handshake protocol. The TC21 and TC26 both run on the same 3.8V cell architecture, so one pack covers the full variant range without modification.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on a TC26 unit and monitored the BMS communication. The protection circuit responded correctly to charge termination and low-voltage cutoff — no false trips under normal scan-and-radio load.
• First-shift cradle prep: After installing, seat the scanner in its charging cradle for a full charge cycle before starting pick-and-pack operations. Scan trigger inrush current is highest when the cell is near minimum — a pre-charged cell prevents false BMS trips on the first shift pull.

Cradle showing charging error on a new pack

A charging error on the dock with a new battery is almost always a contact resistance issue, not a faulty cell. The TC21 cradle uses spring-loaded contacts that pick up warehouse dust and oxidation quickly. Wipe the gold contacts on both the battery and the cradle cup with a dry lint-free cloth, then reseat the scanner firmly. If the error clears within 30 seconds, the contacts were the cause — the pack itself was fine.

Scanner losing wireless connection during rapid scan bursts

During high-frequency scanning, the TC21 draws simultaneously from the imager, the Wi-Fi radio, and the processor. That combined inrush can pull the cell voltage low enough for the BMS to throttle output momentarily, which the radio interprets as a power fault and drops its session. This is more likely on a cell that hasn't completed its first full charge cycle. Charge fully before first use and check that the cradle contacts are clean — a dirty contact adds resistance that worsens voltage sag under load.