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40V 12" Chainsaw Replacement Battery GWG40B2 3000mAh

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From $141.99 USD $186.99
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Fits GreenWorks 40V 12" chainsaw models GWG40B2 and GWG40B4 exactly.
40V nominal, 3000mAh capacity delivers consistent power for limb cutting work.
Connector seats flush into the battery slot with positive locking tab engaged.
We tested under sustained load; BMS held voltage stable through full discharge cycle.
Charge fully before first use; lithium cells in this platform respond best to that initial conditioning.
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⚠️ This item is available by SPECIAL ORDER. Delivery for this product typically takes 2–3 weeks.

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Battery Care Tips

🔹 Getting Started

Charge your new battery fully before you use it for the first time. Over the next few charge cycles, run your device down to around 20% before you recharge—this helps the battery perform its best. After that, charge whenever you need to.

🔹 Keep It Healthy

Avoid letting your battery completely drain or staying plugged in constantly. Both extremes wear it out faster. Store the battery in a cool, dry place when you're not using it, since heat damages batteries quickly.

Delivery and Shipping

🔹 Most orders ship the next day, and we use FedEx, UPS, Purolator and other carriers to get them to you. Lithium batteries have to ship by ground only, not air or USPS. Make sure your address is right before you order, because if we have to send it back, you pay for shipping again.

Disclaimer

⚠️ Disclaimer: All product names, trademarks, and registered trademarks belong to their respective owners.

🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

Voltage

40V

Amp

3000mAh

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.

Compatible Models

40V 12" Chainsaw 2020002 40V 8" Cordless Pole Saw 1403702 40V 15" Cordless String Trimmer 2111802 40V 14" Cordless Dethatcher 2505102 40V Cordless 12" String Trimmer 2111702 1403302 40V 12" Brushless String Trimmer 2110802 40V 20" Brushless Lawn Mower 2516302 40V Cordless Leaf Blower 450 CFM 2416102VT 40V 16" Brushless Cordless Chainsaw 2016802AZ 40V Cordless 20" Brushless Snow Blower 2605302 2411902VT 40V Bucket Pressure Washer 5108402AZ 40V 14" Cordless Dethatcher / Scarifier 2528802 40V 19" Mower Combo Kit w/ Leaf Blower 1341302-VK 40V 14" Brushless Cordless Chainsaw 2012802 40V 16" Cordless Chainsaw 2009702 40V 14" Cordless Lawn Mower 2508202 40V Brushless 19" Lawn Mower 2524902 40V 17" Cordless Lawn Mower / Blower Combo Kit 1306302AZ 40V 21" Brushless Lawn Mower 2515502VT 40V 19” Brushless Lawn Mower 2539602VT 40V Cordless Leaf Blower 500 CFM 2416302AZVT 40V 16" Brushless String Trimmer 2120602AZ 40V Cordless Leaf Blower 350 CFM 2412002VT 40V 21" Brushless Self-Propelled Lawn Mower 2516402 40V 19" Mower Combo Kit w/ String Trimmer & Blower 1341202-VK 40V 14" Cordless Lawn Mower / Blower Combo Kit 1306202AZ 40V 21" Self-Propelled Mower/Axial Blower Combo Kit 1306402AZ 40V 14" Lawn Mower Axial Blower & 12" String Trimmer Combo Kit 1310802AZ 40V 14" Brushless String Trimmer 2110902 40V Cordless Brushless Axial 550 CFM Leaf Blower 2416502AZVT 2525202VT

Replaces Part Numbers

GWG40B2 GWG40B4

Technical Specifications

Voltage40V
Amp Hours3000mAh
Capacity3000mAh
Rate120Wh
Net Weight1160g /40.92 oz
Gross Weight1350g /47.62 oz
Approximate Weight1350g /47.62 oz
Dimension 165.50 x 84.10 x 86.00mm

Product Highlights

  • Brand: GreenWorks
  • Manufacturer: CS
  • Series: Standard
  • Color: Green/Black
  • Product Type: Li-ion
  • Battery Type: Li-ion
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My Greenworks chainsaw keeps cutting out mid-branch — is that the battery dying or something else?

Most likely it's thermal cutoff triggering under sustained load, not a dead battery. The 40V Li-ion cells protect themselves by shutting the tool down when heat builds past a threshold — common when you're cutting dense hardwood or running the bar without enough bar oil, which increases chain drag and draws more current. Let the battery cool for 10–15 minutes off the tool, then check that your chain tension isn't too tight and bar oil reservoir isn't empty before the next cut. If it still drops out on light cuts after cooling, charge the battery to full and check the resting voltage with a multimeter — a healthy 40V pack should read 42V or above when fully charged.

Chain is spinning slower than it should and the motor sounds labored — just put in a new battery

A fresh battery running sluggish on a chainsaw almost always points to voltage sag under load, which happens when a new pack hasn't completed its first full charge-discharge cycle, or when the cells are cold (below about 10°C they deliver noticeably less current). It can also mean the chain is too tight — overtensioned chains create enough drag to make even a good battery look weak. Check chain tension first: the chain should snap back firmly when pulled a quarter inch from the bar. Then run one full charge cycle and retest before assuming the battery is the problem.

Greenworks 40V charger shows solid red and won't switch to green — battery just arrived

Solid red that won't clear usually means the charger detected a cell voltage outside its acceptance window — this happens when a battery has discharged deeply in storage and the charger's protection circuit refuses to begin a standard charge cycle. Some Greenworks 40V chargers have a recovery mode: remove the battery, wait 30 seconds, reinsert it, and watch whether the light briefly flashes before going solid red again — a flash means recovery mode is attempting to trickle-charge the cells back into range. If the light stays solid red with no change after 30 minutes, check the battery terminal contacts for debris or corrosion and clean with a dry cloth. A pack that won't recover past solid red after one hour on the charger has likely been over-discharged past recovery and should be exchanged.

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