KUNLUN 20V 5.5Ah 2 Packs Battery Compatible for Worx 20-Volt Battery WA3575 WA3578 WA3520 WA3525 WA3012 WG151s WG155s WG251s WG255s WG540s WG545s WG890 WG891 20Volt Power Tools | 5.5Ah High Capacity Li-ion Replacement Battery for Worx WA3575 WA3578 WA3520 WA3525 WG151s WG155s WG251s WG540s WG890 WG891

What It Is

This is a two-pack of 20V 5.5Ah lithium-ion replacement batteries designed for Worx 20-volt power tools and lawn equipment. It’s a high-capacity aftermarket option for extending runtime on string trimmers, blowers, mowers, and other battery-powered yard tools that use Worx’s 20V platform.

Fitment & Compatibility

Before buying, confirm your tool uses a Worx 20-volt battery (not 40V or 80V). This battery is compatible with models including WA3575, WA3578, WA3520, WA3525, WA3012, and tools like WG151s, WG155s, WG251s, WG255s, WG540s, WG545s, WG890, and WG891. It is not OEM—it’s a third-party replacement. Check your tool’s battery compartment dimensions: this battery measures roughly 4.5 x 3 x 2.5 inches and weighs about 1.2 lbs. It will not fit Worx 40V or 80V tools, nor other brands like Ryobi or DeWalt. Verify your charger is compatible (Worx WA3740 or similar 20V chargers work).

Key Things to Know

• Installation: Tool-free—slides directly into the battery port. No modifications needed.
• Quality: 5.5Ah capacity is higher than most OEM Worx batteries (typically 2.0–4.0Ah), offering longer runtime but may be slightly heavier. Cells are Li-ion with standard overcharge protection.
• Gotchas: Aftermarket batteries may not charge as quickly in Worx chargers, and some users report slightly shorter lifespan than OEM. Ensure your charger is compatible—older Worx chargers may not recognize third-party batteries. The battery has no fuel gauge; you’ll need to test runtime.
• Performance: Works best for continuous use on tools like string trimmers or blowers, but heavy loads (e.g., mowers) may drain faster than expected.

Should You Buy It

Buy this if you need extra runtime for Worx 20V tools without paying OEM prices, and you’re comfortable with aftermarket reliability. It’s ideal for DIY yard work where two batteries let you swap and keep working. Skip it if you require guaranteed long-term durability or use your tools professionally—OEM batteries may be more consistent.