Winora B0S-20 36V 13000mAh eBike Replacement Battery

Winora B0S-20 / B94-20 Series — 36V Li-ion Replacement Battery

This is a 36V 13000mAh (468Wh) Li-ion battery for Winora eBikes including the B0S-20, B94-20, PASB2, and PASB5 among others. It replaces packs that have lost charge capacity or stopped holding voltage after extended cycling. Voltage and cell chemistry match the original 36V motor drive system.

• B0S-20 / B94-20 platform compatibility: These models share the same 36V battery rail, connector pinout, and BMS communication protocol. Swapping this pack in triggers the same handshake the motor controller expects — no re-pairing or reconfiguration needed.
• Bench tested on actual hardware: We ran this pack through a full charge cycle and simulated sustained motor draw at climbing load. The BMS held voltage above the low-cutoff threshold through the full discharge curve without tripping prematurely.
• First ride after storage: If the bike has sat all winter, charge this battery at a standard rate — not a fast rate — before the first ride. Cold Li-ion cells carry higher internal resistance, and pushing current in too quickly below 10°C causes lithium plating on the anode that permanently reduces cycle life.

E-bike motor cutting out mid-hill on a new battery

Sustained climbing draws peak current for longer than flat riding does. If the pack's internal resistance is slightly elevated — common on a cell that hasn't been fully cycled yet — voltage can sag past the BMS low-voltage cutoff under that load. The motor controller reads this as a depleted pack and shuts assistance off. Run two or three full charge-discharge cycles on flat ground first to condition the cells before tackling long inclines.

Charger not accepting the pack after winter storage

Li-ion chargers have a minimum acceptance voltage — typically around 30V for a 36V pack. If the battery has self-discharged below that threshold during storage, the charger will refuse to start a charge cycle. Connect the charger and leave it plugged in for up to 30 minutes. Most chargers include a trickle pre-charge circuit that slowly raises cell voltage until the main charge stage kicks in. If the charge light activates within that window, the pack has recovered and will charge normally to full.