2-Pack Ryobi OEM 40V 4.0Ah Lithium-Ion Battery set OP4040

What It Is

This is a 2-pack of Ryobi 40V 4.0Ah lithium-ion batteries (model OP4040), designed to power Ryobi’s 40V cordless lawn mowers, trimmers, blowers, and other outdoor equipment. The 4.0Ah capacity offers a balance of runtime and weight for medium-sized yards (up to 1/4 acre).

Fitment & Compatibility

• Brand & model: Only for Ryobi 40V tools. Not compatible with Ryobi 18V or 36V systems.
• Physical check: Measure battery slot depth and width on your tool. The OP4040 is 5.5 x 3.5 x 3.5 inches; ensure your mower’s battery compartment fits these dimensions.
• Deck size: Works with Ryobi 40V mowers with 16-21 inch decks (e.g., RY40180, RY40190). For larger decks (22+ inches), you may need the 6.0Ah or 8.0Ah battery for adequate runtime.
• OEM vs aftermarket: This is OEM Ryobi, so it guarantees proper voltage regulation and fit. Third-party batteries may have slightly different dimensions or lower discharge rates.

Key Things to Know

• No installation needed: Batteries slide in and click; no tools required. But ensure the battery is fully charged before first use (charger not included in this pack).
• Runtime: Approximately 45-60 minutes of mowing on a standard 20-inch deck (depending on grass thickness). For heavy or wet grass, expect 30-40 minutes per battery.
• Common gotcha: The OP4040 uses Ryobi’s “IntelliPort” charge indicator, but it does not have a fuel gauge button. You must check charge level via your tool’s display or charger.
• Storage: Keep batteries at room temperature (50-80°F) and avoid leaving them on the charger for more than 48 hours to prevent cell degradation.

Should You Buy It

If you own a Ryobi 40V mower and need a reliable, OEM backup for medium-sized yards, this 2-pack is a solid choice. It’s not the best value for large properties (consider the 6.0Ah or 8.0Ah), but for typical suburban lawns, the OP4040 delivers consistent power and longevity. Skip it if you need a charger or have non-Ryobi tools.