Powilling 6.5Ah 20V Replacement Battery for Worx Battery 20V WA3578 WA3575 WA3520 WA3525 WG545s,2Pack

What It Is

This is a pair of aftermarket 6.5Ah 20V lithium-ion batteries designed to replace original Worx batteries (WA3578, WA3575, WA3520, WA3525) used in Worx cordless lawn mowers, trimmers, blowers, and other 20V Power Share tools. Higher capacity than most stock Worx batteries, intended for longer runtime.

Fitment & Compatibility

• Works with: Any Worx 20V Power Share tool that accepts the WA3578, WA3575, WA3520, or WA3525 battery packs. This includes popular mowers like the WG545s, WG544, WG543, WG542, WG541, WG520, and WG521, plus trimmers, edgers, and chainsaws in that platform.
• Check this: Confirm your tool uses the slide-on, rear-mount battery style (not the older side-mount or 40V packs). Verify the physical dimensions: ~5.7” long x 3.1” wide x 2.8” tall. These are slightly taller than a 2Ah Worx pack, so measure your battery compartment depth to ensure clearance.
• Not compatible with: Worx 40V tools, 12V tools, or any non-Worx brand. Aftermarket, not OEM—no Worx warranty coverage.

Key Things to Know

• Capacity vs weight: 6.5Ah gives roughly 2–3x runtime of a 2Ah Worx pack, but it’s noticeably heavier (~1.2 lbs each). May affect balance on handheld tools; fine on mowers with a battery tray.
• Installation: Slide on exactly like OEM—no modification needed. Charge with any Worx 20V charger (WA3740, WA3741, etc.). LED indicator on battery shows charge level.
• Quality variance: Some users report slightly shorter lifespan than genuine Worx batteries (fewer charge cycles). Avoid deep discharging—recharge when tool slows to preserve cells.
• Common gotcha: The plastic casing can be a touch tighter than OEM. If it sticks, remove and re-seat; don’t force it.

Should You Buy It

Good for budget-conscious owners of multiple Worx 20V tools who want extended runtime without paying Worx’s premium. Best for mowers or blowers where extra weight isn’t an issue. Skip if you need absolute reliability or warranty support—OEM batteries are safer for heavy daily use.