About this replacement
Symbol PDT6100 / PDT6140 Series — 3.6V Ni-MH Replacement Battery (21-41321-03)
This is a 3.6V, 1800mAh Ni-MH replacement battery for the Symbol PDT6100 series handheld barcode scanners. It fits the PDT6100, PDT6140, PDT6142, and PDT6146 — mobile data terminals used in retail, warehouse, and asset-tracking environments. OEM part numbers covered include 21-41321-03, SM-6100M, 21-33061-01, 21-38678-03, and 21-39369-03.
- PDT6100 series fit: The PDT6100, PDT6140, PDT6142, and PDT6146 all run the same 3.6V battery rail with an identical connector and BMS handshake. One pack covers the full range — no pinout differences between these models.
- Bench tested on actual hardware: We cycled this pack through repeated scan-trigger and wireless polling loads. The BMS held stable across the draw spikes, and cell voltage stayed within the expected Ni-MH discharge curve without premature cutoff.
- First-shift prep for pick-and-pack: Place the scanner in its cradle for a full charge cycle before the first shift. Scan trigger inrush is highest when the cell is near minimum, and a fully charged pack prevents false BMS trips during high-frequency scanning bursts on day one.
Cradle showing a charging error on a new pack
Ni-MH packs that sit in storage ship with low resting voltage. Some Symbol cradles interpret this as a fault condition rather than a deeply discharged cell. The dock checks pack voltage on contact, and if it reads below its threshold, it throws an error instead of initiating a charge cycle. Wipe the battery contact pads and cradle contacts with a dry cloth, reseat the pack firmly, and the cradle should recognise it correctly and begin charging.
Scanner losing wireless connection during rapid scan bursts
The PDT6100 series drives both the scan laser and the wireless radio simultaneously during active scanning. During a rapid burst, the combined inrush from the scan trigger and radio polling can spike the draw beyond what a degraded or partially charged cell can sustain. Voltage sags briefly, the radio drops its connection, and the scanner stalls mid-session. Ensure the pack is fully charged before a high-frequency scanning shift — a full cell handles the combined draw without the voltage sag that trips the radio.