Zebra RS51 Replacement Battery 3.85V 450mAh BTRY-RS51-4MA01

Zebra RS5100 Ring Scanner — 3.85V Li-ion Replacement Battery (BTRY-RS51-4MA01)

This is a 3.85V, 450mAh Li-ion battery for the Zebra RS51 and RS5100 series ring scanners. It fits the RS5100 standard ring scanner and the RS5100 2D Bluetooth Ring Scanner. Capacity figure is from the product specification — 1.73Wh cell in a 42.50 × 29.20 × 13.50mm housing.

• RS51 / RS5100 series fit: These ring scanners share the same battery bay dimensions, connector pinout, and BMS handshake protocol — one cell covers the full platform. The BMS expects a specific charge curve; this pack meets that curve so the device boots cleanly without a low-battery warning on first install.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on the RS5100 platform. The BMS accepted the cell without fault codes, held communication throughout, and the contact voltage settled at 3.85V nominal as expected.
• First-shift prep for ring scanners: After installing the new pack, seat the scanner in its cradle and run a full charge cycle before picking up a shift. The scan trigger draws its highest inrush current when the cell is near minimum — a pre-charged cell prevents false BMS trips when the first burst of rapid scans hits.

Cradle showing a charging error on a new RS5100 pack

The RS5100 cradle reads charging state through the battery contact pads, not through the device itself. A new pack with oxidised or contaminated contacts creates enough resistance that the cradle misreads the cell as faulty. Wipe the gold contact pads on both the battery and the cradle slot with a dry lint-free cloth, then reseat firmly. If the error clears, the cell was fine — the contact surface was the issue.

Scanner losing Bluetooth connection during rapid scan bursts

On the RS5100 2D Bluetooth Ring Scanner, the imager and the Bluetooth radio draw simultaneously during a scan burst. If the cell voltage sags under that combined load, the radio drops before the imager does — the device appears to scan but data stops reaching the host. This is more pronounced when the pack is below 20% charge. Keeping the cell above that threshold during peak-pick periods stops the dropout without any configuration change.