Husqvarna Automower 105 18.5V Replacement Battery 1500mAh

Husqvarna Automower 105 / 305 / 308 — 18.5V Li-ion Replacement Battery (586 57 62-02)

This 18.5V Li-ion battery at 1500mAh (27.75Wh) replaces the original power pack in the Husqvarna Automower 105, 305, and 308 robotic lawn mowers. All three models share the same battery bay geometry, connector, and BMS handshake protocol. Capacity matches OEM spec — use the figure in the product data, not third-party listings.

• Automower 105, 305, and 308 compatibility: These three models run the same 18.5V battery rail with an identical locking tab and two-pin connector. The BMS on each platform reads the same cell parameters, so no firmware conflict occurs on swap-in.
• Bench tested on actual hardware: We cycled this pack under simulated blade-motor inrush loads and confirmed the BMS held protection thresholds consistent with OEM spec. Cell balance at full charge measured within 10mV across all cells.
• Seasonal storage tip: If the mower has sat unused through winter, bring the battery indoors overnight before first use. Below 10°C, Li-ion internal resistance rises sharply — blade motor inrush current can trip the BMS on a cold pack before it even completes its first mowing pass.

Charger showing fault after mower sat in garage all winter

Li-ion cells left in storage self-discharge slowly over months. If the pack drops below roughly 2.5V per cell, the charger's acceptance circuit rejects it as a safety measure — the fault light activates and charging never starts. Some Husqvarna chargers include a recovery mode: connect the pack and hold the charge button for five seconds to initiate a slow pre-charge. If recovery succeeds, the pack will reach a voltage the charger accepts within 15–20 minutes and then proceed to normal charge.

Mower cuts out mid-row then restarts on its own

This is thermal protection triggering, not a faulty battery. When the blade motor works through thick or wet grass, current draw spikes and cell temperature climbs. The BMS cuts output once the thermal threshold is crossed and resets automatically once temperature drops. Let the unit sit for five minutes before resuming — repeated mid-row cutouts in normal grass conditions suggest the pack needs a full charge cycle before assessing further. Check resting voltage after a full charge: it should read 21V or above at the terminals.