DEWALT 20V MAX* Battery, Compact, 4.0-Ah (DCB240)

What It Is

The DEWALT DCB240 is a compact 20V MAX* 4.0-Ah lithium-ion battery for cordless DEWALT tools and select outdoor power equipment. It’s designed to power DEWALT 20V MAX* mowers, trimmers, blowers, and hedge trimmers, offering a balance of runtime and lighter weight compared to larger 5.0-Ah or 6.0-Ah packs.

Fitment & Compatibility

• Brand lock-in: Only works with DEWALT 20V MAX* tools and chargers (not 20V/60V FlexVolt, 54V XR, or other brands).
• Mower fitment: Compatible with DEWALT 20V MAX* mowers (e.g., DCMW220, DCMW225, DCMW240) but check your mower’s battery slot – some mowers use two batteries in parallel; this 4.0-Ah pack fits but may not fill a dual-bay slot fully.
• Charger: Works with all DEWALT 20V MAX* chargers (DCB105, DCB107, DCB115, DCB118). Not compatible with older DEWALT 18V NiCad chargers.
• Physical size: Compact design (about 5.3” x 3.2” x 2.5”) – measure your tool’s battery compartment if you’re unsure about clearance (e.g., under-deck or handlebar mounts).
• OEM vs aftermarket: This is OEM DEWALT; aftermarket 20V batteries may not fit or charge safely.

Key Things to Know

• Runtime: 4.0-Ah provides about 30-40 minutes of mowing on a small lawn (1/4 acre) with a single battery; expect less with heavy grass or on hills. Two batteries in a dual-bay mower give ~60-80 minutes.
• No fuel gauge: Unlike higher-end DEWALT batteries (e.g., DCB205), this pack lacks a charge-level indicator. You’ll need to guess runtime or use a compatible tool that displays battery level.
• Charging time: Takes about 60-90 minutes with a standard charger (DCB105) – plan ahead if you need a quick turnaround.
• Temperature sensitivity: Won’t charge if below 40°F or above 104°F; store indoors in winter to avoid performance loss.

Should You Buy It

Buy this if you already own DEWALT 20V MAX* tools and need a lightweight, reliable battery for light mowing, trimming, or as a backup for smaller yards (under 1/4 acre). Skip it if you need maximum runtime for a large lawn, want a battery with a fuel gauge, or use a different tool platform – consider the 5.0-Ah (DCB205) or 6.0-Ah (DCB206) instead.