Agro R800Li 25.2V Lawn Mower Replacement Battery 3400mAh

Agro R800Li — 25.2V Li-ion Replacement Battery

This is a 25.2V, 3400mAh lithium-ion battery for the Agro R800Li cordless robotic lawn mower. It slots into the mower's battery bay and powers both the cutting deck motor and the drive system. Voltage and capacity match the original factory specification.

• R800Li platform fit: The R800Li runs a single battery rail at 25.2V nominal. The blade motor and drive wheels draw from the same pack, so the BMS must handle both the steady drive load and the short inrush spikes from the cutting deck. This replacement uses a 7S Li-ion configuration to match that rail exactly.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on the R800Li platform. The BMS communicated correctly with the mower's charge controller, protection thresholds triggered as expected, and the pack held its rated capacity across the test cycles.
• 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 even begins cutting.

BMS cutoff during thick-grass or wet-grass blade load

The R800Li blade motor draws significantly more current when cutting dense or wet grass compared to dry, short turf. If that inrush current exceeds the BMS overcurrent threshold — even briefly — the pack shuts down to protect the cells. This is not a battery fault; it is the protection circuit doing its job. To reduce trips, lower the cutting height setting so the deck takes less material per pass, or allow the mower to tackle heavy patches at a slower pace.

Charger refusing to accept the pack after winter storage

A pack left in a garage over winter can self-discharge below the charger's minimum acceptance voltage — typically around 2.5V per cell, or roughly 17.5V at the pack level. When voltage drops that low, the charger's safety circuit reads the pack as faulty and refuses to begin a charge cycle. To recover the pack, use a charger with a wake or recovery mode that applies a low trickle current until the cell voltage climbs above the acceptance threshold. Once the pack reads above approximately 20V, a standard charge cycle should proceed normally.