AL-KO 441188 Cordless Mower Replacement Battery 25.9V 5000mAh

AL-KO Robolino 116 / 4000 Series — 25.9V Li-ion Replacement Battery (441188)

This is a 25.9V, 5000mAh Li-ion replacement battery for AL-KO cordless lawn mowers. It fits the 441188 and 440530 battery platform, covering the Robolino 116, Robolino 4000, and over nineteen compatible AL-KO mower models. Voltage and connector match the original AL-KO specification exactly.

• Robolino 116 and 4000 platform fitment: These models share the same 25.9V battery rail, connector housing, and BMS handshake protocol. A single battery SKU covers all variants in this range without modification.
• Bench tested on actual hardware: We ran this pack through the full AL-KO charge cycle and confirmed BMS communication, cell balancing, and protection cutoffs all responded correctly across discharge and charge phases.
• Seasonal storage tip: If the mower has sat unused through winter, bring the battery indoors overnight before the first spring cut. Below 10°C, Li-ion cells have higher internal resistance, and the blade motor's inrush current can trip the BMS on a cold pack before the cells have a chance to warm up.

BMS cutoff on thick-grass or wet-grass blade load

The AL-KO blade motor draws a sharp current spike when it bites into dense or wet grass. If the pack's state of charge is already below 50%, that inrush can push instantaneous current beyond the BMS protection threshold, triggering an abrupt cutoff. This is a protection event, not a faulty battery. Let the pack rest for two minutes, then resume cutting at a slower walking pace to reduce motor load.

Charger showing a fault light after the mower sat in the garage all winter

Li-ion cells self-discharge slowly during long storage. If cell voltage drops below approximately 2.5V per cell, the charger's intake circuit reads the pack as outside acceptable range and refuses to initiate a charge cycle. To recover it, place the pack in a warm room — above 15°C — for two hours, then reconnect to the charger. Most AL-KO chargers will re-accept the pack once internal temperature stabilises and cell voltage reads above the entry threshold.