Can I use a DeWalt 20V MAX battery on my older DeWalt 18V tools?
Updated: June 15, 2026 | Garage Almanac
The Short Answer
Yes — with DeWalt's official DCA1820 adapter, which lets 20V MAX lithium packs run legacy DeWalt 18V NiCd/NiMH tools.
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The DCA1820 is a genuine DeWalt accessory (not third-party): it accepts a 20V MAX slide pack on top and mounts like an 18V stem pack below, so your old 18V tools keep working on modern lithium batteries. It is tool-use only — you still charge the 20V MAX pack on its own charger. This is the one within-brand adapter DeWalt officially endorses.
Official adapter
Relevant manufacturer accessory: DCA1820. Unlike cross-brand adapters, this is endorsed by the manufacturer.
See the full DeWalt 20V MAX compatibility guide.
Source: https://www.dewalt.com/en-us/product/dca1820/18v-20v-adapter
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