Stiga 325 Replacement Battery 25.2V 10200mAh Li-ion

Stiga 325 / 328S / 520 / 522 Series — 25.2V Li-ion Replacement Battery (1126-9105-01)

This is a 25.2V 10200mAh Li-ion battery pack that replaces OEM part numbers 1126-9105-01, 1126-9138-01, and 1126-9174-01. It fits the Stiga 325, 328S, 520, 522, and over 28 additional Stiga cordless mower models. Capacity is 257.04Wh — matched to the original spec from product data.

• 325 / 328S / 520 / 522 platform fit: These models share the same 25.2V battery rail, connector pinout, and BMS handshake protocol. The pack slots directly into any of them without adapter or firmware change.
• Bench tested on actual hardware: We cycled this pack through simulated blade-motor inrush loads. The BMS held through repeated high-current draw events and balanced cell groups within normal parameters across the test sequence.
• First seasonal use — temperature matters: Before the first mow of the season, bring the battery indoors overnight if temperatures are below 10°C. Cold Li-ion cells carry higher internal resistance, and the blade motor's inrush current on startup can trip the BMS on a pack that hasn't warmed to room temperature.

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

When the cutting deck hits a dense or wet patch, the blade motor draws a short surge of current well above its steady-state load. If that spike exceeds the BMS threshold — common in the Stiga 25.2V platform — the pack shuts down as a protection response. This isn't a battery fault; it's the BMS doing its job. Let the mower sit for five minutes, then restart. If cutouts repeat frequently, reduce forward speed through heavy growth so the motor load stays below the trip point.

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

Li-ion cells self-discharge slowly during storage. After several months, the pack voltage can drop below the charger's acceptance threshold — typically around 20V on a 25.2V system — and the charger refuses to begin a charge cycle, showing a fault or blinking indicator. Some Stiga chargers have a recovery mode: hold the charge button for five to ten seconds to force a low-current pre-charge pulse that brings the cells back above the acceptance floor. If the charger has no recovery mode, measure the pack voltage with a multimeter; anything above 18V is usually recoverable with a compatible charger that supports trickle pre-charge.