Stiga 1126-9105-01 Compatible Battery 25.2V 9000mAh

Stiga 325 / 328S / 520 Series — 25.2V Li-ion Replacement Battery (1126-9105-01)

This 25.2V 9000mAh lithium-ion battery replaces the original pack on Stiga cordless lawn mowers including the 325, 328S, 520, and 522, among others. It matches OEM part numbers 1126-9105-01, 1126-9138-01, and 1126-9174-01. Voltage, connector, and BMS communication all match the original specification.

• Cross-model fit — 325 through 522: These Stiga mower models share the same 25.2V battery platform, connector housing, and BMS handshake protocol. One pack fits across the range without modification.
• Bench tested on actual hardware: We ran this pack through blade-start inrush cycles and sustained cutting loads. The BMS held steady across multiple high-draw events and entered thermal protection only at the expected threshold — no nuisance trips on normal turf.
• Seasonal storage tip: Before packing the mower away at end of season, charge this battery to around 50–60% rather than full. Stiga Li-ion packs stored at full charge over winter experience faster cell degradation — partial charge lowers cell stress during long-term storage.

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

When the blade hits dense or wet grass, the motor draws a sharp inrush of current — significantly higher than normal cutting load. If that spike exceeds the BMS current threshold, the pack cuts power immediately to protect the cells. This is not a fault with the battery; it is the protection circuit doing its job. Reduce deck height by one setting in thick sections, or make a second pass rather than cutting more than one-third of the blade length in a single run.

Charger shows fault light after mower sat all winter

Li-ion cells that self-discharge below roughly 2.5V per cell over a long storage period will be rejected by the standard charger — the BMS sees the pack as outside the safe acceptance window and refuses to initiate a charge cycle. This shows up as a solid fault light or no response from the charger LED. To recover the pack, place it in a warm room (above 15°C) for two hours, then reconnect the charger. If the charger still shows a fault after 30 minutes on charge, check cell voltage with a multimeter — a pack resting below 18V total will need a compatible recovery charger capable of a low-current pre-charge below 2.8V per cell.