Generation and case size, not capacity alone, decide which battery fits a smartwatch. Apple Watch cells are listed for Series 4, 5, 6, 8, SE and SE (2022) in 40, 44 and 45 mm, often with capacity and part number, such as 245 mAh A2277; Samsung Watch 4 Classic, Watch 5 and Watch 5 Pro batteries carry an EB-BR code that matches the label on the original cell. Titles also tell original, OEM and service-pack versions apart.
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Frequently asked questions
How do I know which strap width fits my watch?
Does a smartwatch need its own SIM card?
What does a watch's water resistance actually mean?
Generation and case size, not capacity alone, decide which battery fits a smartwatch. Apple Watch cells are listed for Series 4, 5, 6, 8, SE and SE (2022) in 40, 44 and 45 mm, often with capacity and part number, such as 245 mAh A2277; Samsung Watch 4 Classic, Watch 5 and Watch 5 Pro batteries carry an EB-BR code that matches the label on the original cell. Titles also tell original, OEM and service-pack versions apart.