Electrolux Trilobite 18V Ni-MH Replacement Battery 1128261-01

Electrolux Trilobite ZA1 / ZA2 — 18V Ni-MH Replacement Battery (1128261-01)

This is an 18V, 2200mAh Ni-MH replacement battery pack for the Electrolux Trilobite robotic vacuum cleaner, including the ZA1 and ZA2 variants. It fits the original battery bay and connects to the same BMS interface as the factory pack. OEM part numbers 2192110-02 and 2192119010 are also covered by this replacement.

• Trilobite ZA1 and ZA2 compatibility: All three Trilobite variants share the same 18V battery rail, physical bay dimensions, and BMS communication protocol. One pack covers the full model range without any modification.
• Bench tested on actual hardware: We cycled this pack through the Trilobite's charge-and-run sequence and confirmed the BMS handshake initialised correctly on both the ZA1 and ZA2 dock contacts. Cell voltage held within spec across multiple discharge cycles.
• Dock charging discipline for the Trilobite: Do not leave the Trilobite sitting on its dock continuously between uses. The dock delivers a trickle charge that Ni-MH cells cannot tolerate long-term — it accelerates capacity fade faster than normal cycling. Charge to full, then remove the unit from the dock until the next cleaning run.

Suction dropping before the battery indicator reaches low on the Trilobite

The Trilobite's motor draws harder when airflow is restricted — a partially clogged filter forces the motor to pull above its rated current even with a full charge. The BMS interprets this sustained overcurrent as a load fault and begins throttling power to protect the cells. The result is noticeably weaker suction well before any low-battery signal appears. Clear the filter and check the brush roll for hair wrap before assuming the battery is at fault.

Trilobite not accepting a charge after sitting unused for several months

Ni-MH packs that have self-discharged below approximately 0.9V per cell will often appear dead on the dock — the charger handshake fails because the BMS sees cell voltage below its reinitialisation threshold. This is not always a failed pack. Place the Trilobite on the dock for a full uninterrupted 16-hour charge cycle; the charger's trickle stage can recover cells that have dropped to this level. If pack voltage does not climb above 16V within the first two hours on dock, the cells have likely dropped below recovery threshold and the pack needs replacing.