Gardena 04025-20 Replacement Battery 25V 3000mAh Li-ion

Gardena Accu-Spindelmaher 380 Li — 25V Li-ion Replacement Battery (04025-20)

This 25V 3000mAh (75Wh) Li-ion battery replaces the original pack in the Gardena Accu-Spindelmaher 380 Li cordless cylindrical lawn mower. It fits the 380 Li platform including model references 648872 and Cylinder Lawnmower 380 Li. The battery slots into the same housing as OEM part numbers 04025-20, 8838, and 4025-00.640.00.

• 380 Li platform compatibility: All models in this series run the same 25V bus and share the same connector and BMS handshake. The blade motor inrush current profile is consistent across the range, so one battery spec covers the full 380 Li family.
• Bench tested on actual hardware: We ran this pack through the Gardena 380 Li charge and discharge cycle. The BMS communicated with the charger correctly at each stage and protection circuits engaged at the expected low-voltage cutoff threshold.
• Seasonal storage 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 inrush current on a cold pack can trip the BMS before the mower completes its first pass.

BMS cutoff during thick-grass or wet-grass cutting

The 380 Li blade motor draws significantly more current in dense or damp grass than on a dry, even lawn. When that inrush spike exceeds the BMS current threshold — typically in sustained heavy cutting — the protection circuit shuts the pack down to prevent cell damage. This is not a battery fault. Slow your mowing pace in thick or wet sections to keep the draw below the cutoff point. If the pack shuts mid-row, remove it, wait two minutes, and reinsert — the BMS will reset once the overcurrent condition has cleared.

Charger showing a fault light after the mower sat through winter

If the pack self-discharged below the charger's minimum acceptance voltage during storage, the charger will refuse the charge cycle and show a fault or blinking LED. This is a common outcome when a Li-ion pack sits unused for four or more months. Some Gardena chargers include a recovery or trickle mode — consult the charger label for the fault-light sequence and hold the appropriate button to trigger it. If no recovery mode is available, check cell voltage directly with a multimeter; cells reading above 2.5V per cell are recoverable using a Li-ion recovery charger set to 25V.