Best DeWalt 20V MAX Batteries (2026): 20V MAX vs FlexVolt Explained

Any DeWalt 20V MAX battery works in any DeWalt 20V MAX tool — drills, drivers, saws, and everything else in the lineup. You do not need to match a specific battery model number to a specific tool model number within the 20V MAX platform. The decision that matters is capacity, not fit.

A compact 2Ah pack is light and cheap and works well for drills, drivers, and other light-duty tools where you want minimal weight on the tool. A 5Ah pack costs more and weighs more but runs longer between charges and holds up better under sustained or high-draw use. If you are buying a starter pack or a spare for light tools, 2Ah is usually enough. If you rely on your tools daily or run higher-draw tools, 5Ah is the safer buy.

FlexVolt batteries are backward compatible with the entire 20V MAX lineup — they work in any 20V MAX tool exactly like a standard pack. The difference is that a FlexVolt pack automatically switches to 60V (or 120V paired with a second pack) when used in a FlexVolt-specific tool, like a table saw, miter saw, or mower. That flexibility, plus typically higher capacity, is why FlexVolt packs cost more than standard 20V MAX packs of similar size.

If every tool you own is a standard 20V MAX tool, a FlexVolt pack is a more expensive way to get the same 20V performance, though you do get extra capacity and the option to grow into 60V tools later. If you own or plan to own a FlexVolt-specific tool — the table saws and mowers are the common ones — a FlexVolt pack is the only way to power them, and it doubles as your 20V MAX battery too.

A genuine DeWalt pack carries DeWalt's warranty and is built around DeWalt's tool electronics. Aftermarket FlexVolt-compatible packs, often sold as multi-packs, cost less per Ah but drop that warranty and carry more uncertainty about protection-circuit quality and long-term reliability. They can make sense as a budget spare for lighter use; for daily-driver tools, genuine is the lower-risk choice. See our genuine-vs-aftermarket guide for the full tradeoffs before you decide.