Topcon FC-236 Compatible Battery 3.7V 5200mAh 60991

Topcon FC-236 / FC-336 — 3.7V Li-ion Replacement Battery (60991)

This 3.7V 5200mAh Li-ion battery replaces the OEM 60991 pack in the Topcon FC-236 and FC-336 field controllers. Both units are handheld data collection devices used in surveying and construction. Same cell chemistry, same connector, same BMS-compatible voltage profile as the original.

• FC-236 and FC-336 shared platform: Both field controllers run the same internal power rail and use an identical battery bay and connector. One pack covers both units because the BMS handshake and charge termination voltage are the same across the pair.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on the FC-236 platform. The BMS accepted the cell without error flags, hit full charge termination cleanly, and held stable voltage under sustained scan-trigger and wireless polling load.
• First-shift preparation on the FC-236: After fitting the new pack, seat the FC-236 in its cradle and run a full charge cycle before heading out. Scan-trigger inrush current spikes highest when the cell is near its minimum — a pre-charged pack stops the BMS from tripping on the first burst of rapid barcode reads.

Cradle charging error on a new 60991 pack

The FC-236 cradle reads pack state through spring-loaded dock contacts on the battery face. Oxidation or debris on those contacts raises resistance enough to trigger a charge error, even on a brand-new pack. Wipe the gold contact pads on both the battery and the cradle with a dry lint-free cloth, then reseat the controller firmly. If the error clears, the contact surface was the fault — not the cell or the dock circuit.

Scanner losing wireless connection during rapid scan bursts

The FC-236 pulls from the battery simultaneously for the imager, the processor, and the wireless radio. During a fast burst of scans, the combined inrush from the scan trigger and the radio polling cycle can cause a momentary voltage sag. If the cell voltage dips below approximately 3.2V under that combined load, the BMS may interrupt current to protect the cell, dropping the wireless link. Charge the pack to full before high-frequency scan sessions and avoid running the device below the low-battery warning indicator.