Stiga 325 Replacement Battery 25.2V 6900mAh Li-ion

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

This 25.2V Li-ion pack replaces the original Stiga battery across the 325, 328S, 520, 522 and 28 additional mower models. Capacity is 6900mAh (173.88Wh), matching the OEM specification. It connects via the same locking slide rail and talks to the mower's BMS using the original communication protocol.

• 325 and 328S platform fit: These models share a common 25.2V battery architecture, the same physical rail connector, and the same BMS handshake signal. One pack covers the full group — no adapters or firmware changes needed.
• Bench tested on actual hardware: We ran this pack through full discharge cycles on a 325 deck assembly, monitoring cell voltage and BMS response under simulated blade load. The protection circuit held cutoff at the correct threshold with no false trips on flat terrain.
• Spring start-up tip: Before first use 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 before the cells have warmed to operating temperature.

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

The 325's blade motor draws a sharp inrush current whenever it bites into dense or wet grass. If the battery's state of charge is already below 30%, this spike can push instantaneous current past the BMS cutoff threshold, and the mower stops mid-row. The pack is not faulty — the protection circuit is doing its job. Keep charge above 40% before tackling heavy sections and mow wet grass in a higher cut setting to reduce motor load.

Charger showing a fault light after the mower sat unused all winter

Li-ion cells self-discharge at roughly 2–3% per month. After six months in an unheated garage, cell voltage can drop below the charger's acceptance threshold — typically 2.5V per cell — and the charger refuses to start a charge cycle. Place the battery in a warm room (above 15°C) for two hours first. If the charger still shows a fault, attempt a brief 30-second connection to a compatible 25.2V charger to nudge cell voltage above the acceptance floor, then restart a normal charge.