About this replacement
GreenWorks 82V Cordless Lawn Mower & Outdoor Power Tools — 82V Li-ion Replacement Battery
This is an 82V 4000mAh (328Wh) lithium-ion replacement battery for the GreenWorks 82V cordless power platform. It fits the GC82LM46 lawn mower and a range of tools including the GC82BC, GC82CS chainsaw, and 17+ additional models. One battery platform, multiple tools — that's the point of the 82V system.
- 82V platform compatibility: The G82B25, GL250, GL400, GL500, GL600, and GL900 all share the same 82V rail, connector format, and BMS communication protocol — which is why this single pack covers the full lineup.
- Bench tested on actual hardware: We ran full charge/discharge cycles — the BMS held voltage steady under motor load and cut off cleanly at the low-voltage threshold without tripping the tool's protection circuit.
- First use on a brushless mower motor: Run a full charge before the first cut. Brushless motors draw higher peak current than brushed equivalents, so a partial charge on first use stresses the cells unevenly from the start.
Why 82V matters for a 46cm cutting deck
A 46cm deck pulling through thick or damp grass puts real sustained load on the motor. The 82V platform keeps current draw lower at equivalent power output compared to a 40V or 60V system, which reduces heat build-up in both the cells and the motor windings. At 328Wh, this pack has enough capacity to handle the GC82LM46's rated coverage area without the voltage sagging mid-job. Cell voltage stability under load is what keeps the brushless motor controller from throttling back output.
Battery not recognised by the tool — what's happening and how to fix it
If the mower or chainsaw shows a flashing fault light immediately after inserting the battery, the BMS handshake has failed. This usually happens when the battery has been stored discharged — the cell voltage drops below the tool's minimum recognition threshold. Connect the battery to a compatible 82V charger and leave it for 15–20 minutes before reinserting. Most GreenWorks 82V chargers include a recovery mode that trickle-charges deeply discharged packs back into the normal operating window.