Wolf Garten Power 37 Compatible Battery 36.5V 4000mAh

Wolf Garten Power 37 / Power 40 Series — 36.5V Li-ion Replacement Battery (4949066)

This is a 36.5V, 4000mAh (146Wh) Li-ion replacement battery for the Wolf Garten Power 37, Power 40, Hybrid Power 37, and Hybrid Power 40 cordless lawn mowers. It replaces OEM part numbers 4949066, 4937065, and 4919096, as well as the LI-ION Power Pack 2 specification. When the original pack loses capacity or stops holding charge, this unit restores the mower to full operation without replacing the machine.

• Power 37, Power 40, Hybrid 37, Hybrid 40 compatibility: All four models share the same 36.5V battery rail, connector format, and BMS handshake protocol. A single pack covers the full platform — no adapter or firmware change needed.
• Bench tested on actual hardware: We ran this pack through full discharge-recharge cycles on a Power 37 deck. The BMS held stable across standard cutting loads and responded correctly to both low-cell and over-temperature cutoff conditions.
• Cold-weather start tip: 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 can trip the BMS on a cold pack before cutting even begins.

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

The Power 37 blade motor draws a sharp inrush current every time it bites into dense or wet grass. If that spike exceeds the BMS threshold — which drops lower on a warm or partially discharged pack — the battery cuts out to protect the cells. This is not a fault with the pack; it is the protection circuit doing its job. Mowing in overlapping passes at reduced width reduces peak draw and keeps the BMS from tripping mid-row.

Charger shows fault light after mower sat unused all winter

Li-ion cells self-discharge slowly over months of garage storage. If the pack drops below approximately 2.5V per cell, most chargers refuse to begin a charge cycle and show a fault or red indicator light. To recover the pack, leave it connected to the charger for 20–30 minutes without unplugging — some chargers trickle-charge at a lower current until the cell voltage climbs back above the acceptance threshold. If the charger still shows a fault after 30 minutes, the cells have likely dropped below recoverable voltage and the pack needs replacing.