About this replacement
GreenWorks 40V Chainsaw & Pole Saw — 40V Li-ion Replacement Battery
This 40V 3000mAh lithium-ion pack replaces the GWG40B2 and GWG40B4 batteries used in GreenWorks 40V chainsaws and pole saws. It fits the 12" cordless chainsaw, the 8" cordless pole saw, and 61 additional 40V platform tools. Capacity is 120Wh at 40V nominal.
- Platform-wide compatibility: All listed models share the same 40V lithium-ion rail, connector housing, and BMS communication protocol — one pack works across every tool in the GreenWorks 40V lineup.
- Bench tested on actual hardware: We ran full charge/discharge cycles across chainsaw and pole saw loads — the BMS held voltage steady under bar resistance and tripped the low-voltage cutoff cleanly without cell reversal.
- First charge on a new pack: Run a full charge before the first cut. Li-ion cells ship partially discharged for transport safety — topping up first lets the BMS calibrate state-of-charge accurately from the start.
Why chain load matters for battery longevity
A dull or over-tensioned chain draws higher current from the pack on every cut. That sustained overcurrent stresses cells and accelerates capacity loss. Keep the chain sharp and tensioned to GreenWorks spec — the battery lasts longer because the motor isn't fighting extra drag.
Chainsaw won't start after sitting — and how to fix it
If the saw refuses to start after the pack has sat unused for weeks, the BMS may have tripped into deep-sleep mode to protect cells at low voltage. Remove the battery, press the charge button on the pack once, then place it on the charger immediately. The charger's trickle stage wakes the BMS and brings the cells back to a normal operating range.