Earthwise Power Tools by ALM BL80204 20-Volt 4.0Ah Replacement Lithium-Ion Battery

What It Is

The Earthwise BL80204 is a 20-volt, 4.0Ah lithium-ion replacement battery designed to power Earthwise cordless lawn mowers, trimmers, blowers, and other 20V tools in their lineup. It’s a direct replacement for the original battery that came with your machine.

Fitment & Compatibility

• Check your model number: This battery fits Earthwise 20V tools, including mowers like the SWM72020, SWM72015, and SWM72010, and trimmers like the ST70020. Confirm your tool model in the manual or on the battery compartment label.
• Voltage & chemistry: Must be 20V max (same as original). It’s lithium-ion, so it won’t work with older Earthwise 18V or 24V systems—those use different connectors.
• Physical dimensions: The battery measures about 5.5 x 3.5 x 3 inches. Measure your battery slot before buying to ensure it fits (especially on compact mowers).
• OEM vs aftermarket: This is an Earthwise-branded OEM battery, not a third-party knockoff. It’s the correct replacement for warranty and performance purposes.

Key Things to Know

• Installation is tool-free: Slides into the battery port with a click. No wiring or tools needed.
• Run time: 4.0Ah gives roughly 45–60 minutes on a trimmer or 20–30 minutes on a mower (depending on grass conditions). Lower than the original 5.0Ah if your mower came with one.
• Charger compatibility: Works with the Earthwise 20V charger (model CH20V). If you have an older 18V charger, it won’t charge this battery—you’ll need a new one.
• Storage tip: Store at room temperature, partially charged (40–60%) if not using for months. Avoid full discharge to extend lifespan.

Should You Buy It

Buy this if you need a reliable, direct-fit replacement for your Earthwise 20V tool and want OEM quality without guessing compatibility. It’s a solid choice for light to medium use, but if you need longer run time for a large lawn, consider a higher-capacity 5.0Ah battery instead.