LG A9K-CORE1S Replacement Battery 25.9V 2500mAh

LG CordZero A9K-CORE1S — 25.9V Li-ion Replacement Battery (EAC63382214)

This 25.9V, 2500mAh Li-ion battery replaces the original pack in the LG CordZero A9K-CORE1S and compatible A9K-series stick vacuums. It fits the A9Komp, CordZero A9S, and CordZero A9k platforms that share the same voltage rail and battery housing. Swap it when suction drops noticeably before the indicator reaches low, or when the original pack no longer holds a charge.

• A9K-series platform fit: The A9K-CORE1S, A9Komp, A9S, and A9k share the same 25.9V battery architecture, slide-lock connector, and BMS communication protocol. One cell works across all these models because LG standardised the battery interface across the CordZero A9 generation.
• Bench tested on actual hardware: We ran this cell through the A9K motor start cycle and sustained suction load. The BMS held the 25.9V rail without nuisance tripping, and the charge handshake with the original LG dock completed correctly on first connection.
• Dock charging discipline for CordZero vacuums: Do not leave the vacuum seated on the charging dock permanently. CordZero models on continuous dock charge develop capacity fade significantly faster than those charged only when depleted. Charge to full, then remove the vacuum from the dock.

Suction dropping before the battery indicator reaches low

The A9K motor draws more current as filter restriction increases. A degraded battery can't sustain the 25.9V rail under that elevated load, so the motor slows and suction drops — even though the indicator still shows charge remaining. The BMS is protecting the cell from over-discharge under peak draw, not reporting a flat battery. Check and clean the filter first; if suction still drops on a clean filter, the cell has aged past its usable capacity and needs replacement.

Motor cuts out mid-clean then recovers after a few seconds

This is a BMS overcurrent trip, not a power-off event. When the A9K runs over a blockage or a heavily restricted filter, the motor spikes its current draw beyond what the BMS allows. The BMS cuts the circuit to protect the cell, then resets once current normalises. The fix is to clear any blockage and wash the filter — if the cutout happens repeatedly on a clean, unblocked machine, the replacement cell's BMS is responding to internal resistance in the old pack. Fitting a new cell with a healthy BMS resolves the trips.