About this replacement
Signalfire AI-7 / AI-8 Fusion Splicer Series — 11.1V Li-ion Replacement Battery (ZS26F)
This 11.1V 7800mAh Li-ion pack replaces the ZS26F battery in the Signalfire AI-7, AI-7C, AI-8, and AI-8C Optical Fiber Fusion Splicers. It powers the arc fusion and motor drive circuits that align and splice optical fiber. At 86.58Wh, it matches the original capacity spec for full-shift field operation.
- AI-7 / AI-8 platform compatibility: The AI-7 and AI-8 series share the same battery bay format, connector pinout, and BMS communication protocol. One pack covers both platforms. The AI-7C and AI-8C compact variants use the same electrical interface — no adapter needed.
- Bench tested on actual hardware: We cycled this pack through splicer arc sequences and fiber motor drive loads. The BMS held voltage across repeated arc events and motor stepping without triggering overcurrent cutoff. Cell balancing completed within two full charge cycles.
- Post-install calibration on the AI-7: After fitting this pack, run the splicer through one full arc calibration sequence from the menu before heading to site. The AI-7 maps battery state during that calibration pass — skipping it causes the low-battery indicator to trip early during the first splicing session, even with a full charge.
Why the AI-7 cuts power during the arc fusion sequence
The arc electrodes and fiber alignment motors draw current simultaneously at fusion trigger. On a degraded or deeply discharged pack, this combined spike can push instantaneous draw past the BMS overcurrent threshold. The splicer shuts down mid-arc to protect the cell — not a unit fault. A healthy pack at full charge handles the surge without dropout. If shutdowns happen on a new pack, confirm the battery voltage reads above 11.0V at the splicer status screen before starting a splice sequence.
Splicer not recognising the new pack after extended storage
A Li-ion pack stored unused for several months can drop below the BMS recovery threshold — typically around 9V for an 11.1V three-cell pack. Below that point, the BMS enters sleep mode and the splicer sees no communication from the battery, displaying a battery error or simply not powering on. Connect the pack to its charger for at least 30 minutes before inserting it into the splicer — most chargers will push a recovery trickle charge that wakes the BMS. Once voltage climbs above 10.5V, the splicer will recognise the pack normally.