Eloik ALK-618650A Survey Battery 10.8V 5200mAh Li-ion

Eloik ALK-80 / ALK-88 Series — 10.8V Li-ion Replacement Battery (ALK-618650A)

This is a 10.8V, 5200mAh (56.16Wh) Li-ion replacement battery for the Eloik ALK-80, ALK-88, ALK-88A, and HH-88 survey and measurement instruments. It uses OEM part number ALK-618650A and fits the same battery bay without modification. Voltage and connector match the original pack exactly.

• ALK-80 / ALK-88 platform compatibility: All four fit models share the same 10.8V power rail, connector pinout, and BMS handshake protocol. The instrument draws battery identification data through the same contact array on each unit, so one pack covers the entire platform without any firmware conflict.
• Bench tested on actual hardware: We cycled this pack through full charge and discharge on a load tester configured to simulate the combined draw of the ALK-80 sensor array and display. The BMS responded correctly to charge termination, over-discharge cutoff, and short-circuit protection at each threshold.
• First-use calibration before field deployment: After installing this pack, run a full calibration cycle through the instrument menu before taking it to site. The ALK-80 maps battery state during that calibration pass — skipping it causes the low-battery indicator to fire early on the first measurement session, even with a fully charged pack.

BMS cutoff when the ALK-80 probe module powers up

When the ALK-80 initialises its probe or sensor module, it pulls a short current spike that can exceed the BMS protection threshold of an aged or cold cell pack. A healthy pack at full charge absorbs this spike without tripping. An aged pack with elevated internal resistance sees a momentary voltage sag that crosses the BMS cutoff point, causing an immediate shutdown. This replacement pack has a lower internal resistance profile that handles the initialisation spike without triggering protection. If the instrument still cuts out on probe startup, charge the pack to 12.6V before retrying — cold cells sag harder than warm ones.

Pack will not charge after months sitting unused in a carry case

Li-ion cells self-discharge slowly over storage. If an ALK-618650A pack drops below approximately 9V during a long storage period, the BMS enters sleep mode and blocks the charge path as a safety measure. A standard charger sees no response and stops — it looks like a dead pack. To recover it, use a charger with a recovery or boost mode that applies a low precharge current (around 100mA) to bring the cell voltage back above the BMS wake threshold of roughly 9.5–10V. Once the BMS wakes, normal charging resumes. If the pack does not respond after 30 minutes of precharge, the cells have dropped below recovery voltage and the pack should be replaced.