40V Lithium-ION 4.0 AH Battery

What It Is

This is a 40V, 4.0 Ah lithium-ion replacement battery designed for cordless lawn mowers, string trimmers, blowers, and other outdoor power equipment that uses a 40V platform. It provides extended runtime compared to smaller 2.0 or 2.5 Ah packs, making it suitable for mid-sized yards (up to 1/3 acre) on a single charge.

Fitment & Compatibility

Before buying, verify three things:

• Voltage match: Must be a 40V system. This battery will not work with 18V, 20V, 56V, or 80V tools.
• Brand-specific slide/click interface: This is a generic “Lithium-ION” branded battery. It may fit some universal 40V tools, but it is not guaranteed to work with proprietary brands like Greenworks, Kobalt, Ryobi, or EGO. Check the terminal shape and locking tab position against your tool’s battery port.
• Physical dimensions: Measure your original battery’s length, width, and height. This battery measures roughly 5.5" x 3.5" x 3". If your tool has a recessed or tight battery compartment, confirm clearance.
• OEM vs aftermarket: This is an aftermarket replacement. It may lack the fuel-gauge LED or over-discharge protection found on OEM packs. Test fit before relying on it for heavy use.

Key Things to Know

• Quality: 4.5/5 stars from 3,500+ reviews suggests good reliability, but some users report shorter lifespan (1–2 seasons) compared to OEM batteries under frequent deep discharge.
• Installation difficulty: None. Slide battery into tool’s port until it clicks. Remove by pressing the release button and pulling out.
• Common gotchas:
  • Charger compatibility: Only works with a 40V lithium-ion charger. Do not use with a NiCad or 20V charger.
  • Storage: Store at 40–80°F. Freezing or heat above 100°F can permanently reduce capacity.
  • No compatibility with 40V tools that use a “stacked” or “top-mount” battery design (e.g., some Worx or Snapper models).

Should You Buy It

Buy this if you need a budget-friendly spare 40V battery for a universal or compatible tool, and you don’t mind slightly shorter overall lifespan than OEM. Skip it if you require exact fitment for a brand-specific tool (like Greenworks or Kobalt) or need a battery with built-in charge indicators and rugged weather sealing for commercial use.