2Packs WA3520 7.0Ah Li-ion Replacement for Worx 20V Battery Lithium WA3525 WA3575 WA3578 Compatible with Worx Battery 20 Volt WG151s WG155s WG251s WG890 WG891 Cordless Tools

What It Is

This is a two-pack of 7.0Ah lithium-ion replacement batteries designed for Worx 20V cordless tools, including lawn mowers like the WG151s, WG155s, and WG251s, as well as trimmers, blowers, and other 20V Worx equipment. It serves as a higher-capacity alternative to standard Worx batteries, extending runtime for medium-to-heavy yard work.

Fitment & Compatibility

Before buying, verify your tool uses Worx’s 20V slide-on battery platform (rectangular base with two rails). This pack replaces OEM models WA3520, WA3525, WA3575, and WA3578. It fits Worx 20V mowers: WG151s, WG155s, WG251s, WG890, WG891, and many trimmers/blowers (e.g., WG119s, WG175). Not compatible with 40V or 12V Worx tools. Check your tool’s battery compartment for the slide-lock mechanism and ensure the terminal orientation matches (positive/negative tabs align). No deck size or measurement checks needed—fitment is purely battery interface.

Key Things to Know

• Capacity vs. OEM: 7.0Ah is higher than most Worx original batteries (typically 2.0–5.0Ah), so runtime may significantly increase, but charging time will be longer with standard Worx chargers.
• Quality concerns: 3.7/5 rating suggests mixed reliability—some users report shorter lifespan or cell degradation after 6–12 months. Inspect for swelling or overheating on first charge.
• Installation: Tool-free; slides into battery port until it clicks. Ensure the locking tab engages fully to avoid disconnection during mowing.
• Charger compatibility: Works with any Worx 20V charger (e.g., WA3742, WA3880), but using a fast charger may reduce battery life over time.

Should You Buy It

Buy this if you need extended runtime for large lawns or frequent trimming on a budget, and you’re willing to accept potentially lower longevity than OEM packs. It’s a decent value for light-to-moderate use, but if reliability is critical (e.g., commercial use), stick with genuine Worx batteries.