Ferrex CA0005 20V Lawn Mower Replacement Battery 2500mAh

Ferrex R800 Smart — 20V Li-ion Replacement Battery (CA0005)

This is a 20V Li-ion battery with 2500mAh capacity, built to replace the original pack in the Ferrex R800 Smart cordless lawn mower. It slots directly into the R800 Smart's battery bay and connects to the same charge management system as the factory pack. Voltage and cell chemistry match the original specification exactly.

• R800 Smart platform fit: The R800 Smart runs a 20V motor rail with a BMS handshake that checks cell voltage and thermistor signal before allowing motor start. This pack carries both — the connector pinout and thermistor line match what the mower's control board expects at startup.
• Bench tested on actual hardware: We cycled this pack through simulated blade-load draws on a 20V test rig. The BMS held steady through inrush spikes at motor start and throttled correctly as cell temperature rose under sustained load.
• Seasonal storage tip: Before first use in spring, bring the pack indoors overnight if temperatures are below 10°C. Cold Li-ion cells have higher internal resistance, and the blade motor's inrush current can trip the BMS on a cold pack — even one that shows full charge.

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

The R800 Smart's blade motor pulls significantly more current through dense or wet grass than on a dry, short lawn. When that inrush exceeds the BMS current threshold, the pack cuts out as a protective measure — not a fault in the battery. The fix is to slow your mowing pace so the blade isn't fighting a wall of resistance all at once. Overlapping passes on thick sections reduces peak draw and keeps the BMS from tripping mid-row.

Charger rejecting the pack after winter storage

Li-ion cells left in storage over winter can self-discharge below the charger's minimum acceptance voltage — typically around 2.5V per cell. When that happens, the charger reads the pack as faulty and refuses to initiate a charge cycle. Many chargers have a recovery or trickle mode: leave the pack connected for 10–15 minutes and the charger will often step in with a low-current pre-charge to bring cells back above the acceptance threshold. If the pack reaches 3.0V per cell, normal charging resumes.