2 Packs WA3525 4.0Ah Replacement for Worx 20V Battery WA3520 WA3577 WA3578 WG151S WG155S WG251S Compatible with Worx Batteries 20V Tools

What It Is

This is a two-pack of 4.0Ah replacement lithium-ion batteries for Worx 20V cordless tools, including lawn mowers, trimmers, blowers, and chainsaws. It’s designed to power any Worx 20V tool that uses the WA3520, WA3577, or WA3578 battery platform.

Fitment & Compatibility

• Tool compatibility: Fits all Worx 20V tools that accept WA3520, WA3577, or WA3578 batteries. Common lawn mowers include WG151S, WG155S, WG251S. Also works with trimmers (e.g., WG163), blowers (e.g., WG520), and chainsaws (e.g., WG303).
• OEM vs aftermarket: This is an aftermarket replacement, not a genuine Worx battery. It will fit physically and electrically, but may have slightly different performance or lifespan.
• Physical fit: The battery slides into the same slot as OEM batteries. No modifications needed.
• Voltage and capacity: 20V nominal (max 21.6V), 4.0Ah per battery. This is a step up from the standard 2.0Ah packs, giving longer runtime.
• What to check: Verify your tool’s battery port shape (Worx 20V is a unique slide-mount design). Also confirm your charger is compatible—these batteries use the same charging port as OEM packs.

Key Things to Know

• Runtime: 4.0Ah provides roughly double the runtime of a standard 2.0Ah battery. For a 20V mower, expect about 30–45 minutes of mowing per battery, depending on grass conditions.
• Charging: Use a Worx 20V charger (e.g., WA3730, WA3880). Charging time is typically 1–2 hours per battery. Avoid using third-party chargers not rated for lithium-ion.
• Quality note: Aftermarket batteries may not hold charge as long or last as many cycles as genuine Worx packs. Some users report slight differences in fit (tight or loose), but most work fine.
• No tools required: Installation is simply slide-in, click, and use. No wiring or modification needed.

Should You Buy It

If you have multiple Worx 20V tools and need extra runtime without buying expensive OEM packs, this two-pack is a solid value. It’s ideal for users who mow a medium-sized lawn or run several tools in a session. However, if you prioritize maximum lifespan and reliability over cost, stick with genuine Worx batteries.