Symbol MC50 Barcode Scanner Replacement Battery BTRY-MC50EAB02 3.7V 3600mAh

Symbol MC50 / MC5040 — 3.7V Li-ion Replacement Battery (BTRY-MC50EAB02)

This is a 3.7V, 3600mAh Li-ion battery for the Symbol MC50 and MC5040 mobile computers. These rugged handheld scanners are used in warehouse, retail, and field service environments where a dead battery stalls an entire picking shift. The OEM part numbers this replaces are BTRY-MC50EAB02 and 21-67315-01.

• MC50 and MC5040 fit: Both models share the same battery bay, connector pinout, and BMS handshake protocol — a single cell covers both. The pack communicates charge state to the device over the SMBus line, so the battery gauge on screen reflects actual cell voltage.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on an MC50 unit. The BMS engaged correctly at low-voltage cutoff and the cradle charger completed a full charge cycle without a fault flag.
• First-shift prep for pick-and-pack: After installing, seat the scanner in its cradle for a full charge cycle before using it in production. Scan trigger inrush current is highest when the cell is near minimum — a pre-charged cell prevents false BMS trips during the first burst of the shift.

Cradle showing a charging error on a new pack

A charging error on a freshly installed pack is usually a contact resistance issue, not a faulty cell. The MC50 cradle reads pack voltage through the battery contacts — even light oxidation on the gold pads raises resistance enough to trigger a fault. Wipe the contacts on both the pack and the cradle with a dry cloth, then reseat the scanner firmly until it clicks. If the error clears within 30 seconds, contact resistance was the cause.

Scanner losing wireless connection during rapid scan bursts

The MC50 draws from the same cell for both the wireless radio and the scan trigger. During a rapid scan burst, the combined inrush from the imager and the 802.11 radio can pull voltage down momentarily. If the cell is partially discharged, this sag crosses the radio's minimum operating threshold and the connection drops. Charge the pack to full before a high-volume shift and check that the cell rests above 3.6V between bursts — below that, sag under combined load becomes more pronounced.