Is a Stanley V20 battery 20V or 18V?

Both — it is one battery described two ways. 20V is what it measures fresh off the charger with nothing drawing from it; 18V is what it settles at under load, and that is the figure most other brands print on the tool. So a 20V battery and an 18V tool are the same class of battery, which is exactly why an adapter between them works.

How do I find the right adapter on this page?

Use the selector at the top: pick the platform on the other side of the pair and it takes you straight to the one adapter that joins them. Every combination in that list is one we actually make, so if it is there, it exists.

Can I go the other way round — run Stanley V20 tools from another brand’s battery?

Yes. Use the swap button next to the selector above and the page turns the search around, from Stanley V20 tools back to the batteries that can run them.

Can I charge a Stanley V20 battery through the adapter?

No. The adapter carries current from the battery to the tool and does nothing else — there is no charging circuit inside it. Keep charging Stanley V20 batteries on their usual Stanley charger.

Will an adapter damage my Stanley V20 battery or my tool?

Used with undamaged, compatible equipment it is not expected to. Stanley V20 batteries are lithium-ion with their own protection circuit built into the battery, and it keeps doing its job through the adapter. Stop when the tool noticeably slows rather than running the battery flat, and stop using the adapter if it becomes unusually hot or the contacts look damaged.

Does it work with third-party Stanley batteries?

Usually. What matters is the socket, not the badge: if the battery slides onto a Stanley V20 tool and locks the way an original does, the adapter will take it. Aftermarket batteries do vary in moulding, so if yours looks unusual send us a photo and we will check before you order.