Comptyco A-81S Fusion Splicer Compatible Battery 11.1V 7800mAh

Comptyco A-81S Fusion Splicer Series — 11.1V Li-ion Replacement Battery (A-81S)

This is an 11.1V, 7800mAh Li-ion replacement battery for the Comptyco A-81S, FS-60C, and FS-60F fusion splicers. These splicers are used in the field to permanently join optical fibers, often in locations where AC power is unavailable. Voltage and capacity match the original pack exactly — 11.1V nominal, 86.58Wh total energy.

• A-81S, FS-60C, and FS-60F compatibility: All three splicers run the same 11.1V three-cell Li-ion architecture with the same physical connector and BMS communication protocol. The battery handshake is identical across the series, so one pack covers all three models without modification.
• Bench tested on actual hardware: We ran this pack through arc discharge cycles and motor-drive sequences on the splicer platform. The BMS held stable across repeated electrode advance cycles and high-draw arc events without triggering overcurrent cutoff.
• Field deployment prep for fusion splicers: After fitting this pack, run the splicer through a full arc calibration sequence before heading out — the A-81S maps battery state during calibration, and skipping it causes the low-battery indicator to trip early on the first splicing session in the field.

BMS cutoff during electrode advance and arc firing on the A-81S

The A-81S draws a sharp current spike each time the electrode motors advance and the arc fires in sequence. On a degraded or deeply discharged pack, that combined spike can push instantaneous draw past the BMS overcurrent threshold, triggering a shutdown mid-splice. This replacement pack uses cells rated for the sustained and peak current the splicer demands across a full work session. If the unit shuts down at arc initiation specifically, fully charge the new pack before the first use and confirm the arc calibration sequence completes without interruption.

Splicer not recognising the new pack after it sat uncharged for months

Li-ion packs that sit unused for an extended period can self-discharge below the BMS recovery threshold — typically around 2.5V per cell. When voltage drops that low, the BMS enters sleep mode and the splicer sees no pack at all, or displays a battery fault on boot. Connect the pack to the charger and leave it for at least 30 minutes before powering the splicer on — most chargers will trickle charge a sleeping BMS back above the 9V pack-level recovery threshold. Once the charger indicator shows active charging, the BMS has re-initialised and normal charge will proceed.