About this replacement
Eloik BY-A6 / BY-A6s — 11.1V Li-ion Replacement Battery (ALK-618650S)
This 11.1V, 5200mAh (57.72Wh) Li-ion battery replaces the OEM pack in the Eloik BY-A6 and BY-A6s fusion splicer and field test instruments. It fits both models — same connector, same BMS handshake, same voltage rail. Capacity figure is taken from the product data, not estimated.
- BY-A6 and BY-A6s compatibility: Both models share the ALK-618650S form factor, connector pinout, and 11.1V nominal rail. The BMS on each instrument communicates cell state the same way, so one pack covers both without modification.
- Bench tested on actual hardware: We cycled this pack through full charge and discharge on the bench, monitoring BMS cutoff thresholds and cell voltage balance under sustained sensor load. The protection circuit held within spec across all test cycles with no unexpected trips.
- First-use calibration on the BY-A6: After installing, run a full calibration cycle through the instrument menu before field deployment. The BY-A6 maps battery state during calibration — skipping this step causes premature low-battery warnings in the first measurement session, even when the pack is fully charged.
BMS cutoff when the BY-A6 powers up probe or arc modules
The BY-A6 draws a sharp current spike the moment arc electrodes or optical probe modules initialise. A degraded or deeply discharged original pack can drop below the BMS undervoltage threshold during that spike, triggering an immediate shutoff. This replacement pack's cells are balanced to hold voltage during the inrush event. If the instrument cuts out at module initialisation, verify cell voltage is above 10.5V before the next boot attempt.
Pack sits unused for months — BY-A6 won't recognise it on reinstall
Li-ion cells self-discharge over storage, and after several months the pack voltage can fall below the BMS recovery threshold — typically around 9V for an 11.1V three-cell pack. When voltage drops that low, the BMS enters sleep mode and the instrument treats the pack as absent or faulty. Connect the pack to the OEM charger for at least 15 minutes before reinserting it; this wakes the BMS and allows the instrument to re-establish communication. If the charger shows no activity, check charger output voltage is present before assuming the pack is dead.