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Research Topic: Which Battery Will Do?

Last updated:	Overview & Terms 8 March 2012		Single Use 7 January 2016		Rechargeable 10 November 2019		Battery Analyser 23 April 2021		Battery/Charger Shopping 24 April 2021		Recommended Batteries for Particular Uses 16 May 2014
Original article by Ian Mander, 22 July 2002			Single Use Test 6 November 2007		Rechargeable Test 21 September 2023		Test Procedure 4 June 2011		Button and Coin Cell Shopping 31 July 2021		More Info & Links 29 February 2012
					LSD Shootout 7 January 2016		When Battery Testing Goes Bad – Consumer Magazine 20 June 2023		Battery Holder Shopping 28 July 2022

Safety note

Button and coin cells must be kept away from young children who might swallow them. See this article for more information about the hazards.

Shopping for button and coin cells

These are available inexpensively online, if you don't mind waiting for international shipping. Silver oxide cells (SR...) have more capacity than alkaline cells (LR...), have a nominal voltage slightly higher (1.55V instead of 1.5V) and are also more expensive. Zinc air cells are most often used for hearing aids.

Watch battery notes

• The W on the end of an SR number (eg, SR626SW) means it's specifically designed for watch use – it meets the international IEC 60086-3 standard for watch batteries.
• An S in the suffix (eg, ...SW) means it uses sodium hydroxide for the electrolyte, which Energizer says is suitable for continuous low drain devices, such as watches (source – Energizer silver oxide application manual).
• Less common is a P suffix (eg, ...PW), which means potassium hydroxide electrolyte, suitable for continuous low drain with periodic high drain pulse demands, or "high drain" (eg, watches with alarms, backlights, calculators, etc).
• The potassium hydroxide cells are harder to seal and thus have less salt resistance.
• Just a W suffix does not necessarily indicate either low drain or high drain, but for at least some companies including Maxell and Renata it means high drain. Sadly, resellers are very likely to get mixed up, so if you want a particular type, be careful.
• Low drain/high drain does not mean low capacity/high capacity. A Renata 395 (SR927SW, low drain) is 55 mAh, a Renata 399 (SR927W, high drain) is 53 mAh. (Source – Renata datasheet.)
• For most uses it probably doesn't matter.

The cells in this table are listed by size, diameter first. Often a thicker or thinner cell will fit.

Remember to check how many you need – some watches take two cells.

alkaline button cells | lithium coin cells | rechargeable lithium coin cells | zinc air (hearing aid) button cells

Last updated:	Overview & Terms 8 March 2012		Single Use 7 January 2016		Rechargeable 10 November 2019		Battery Analyser 23 April 2021		Battery/Charger Shopping 24 April 2021		Recommended Batteries for Particular Uses 16 May 2014
Original article by Ian Mander, 22 July 2002			Single Use Test 6 November 2007		Rechargeable Test 21 September 2023		Test Procedure 4 June 2011		Button and Coin Cell Shopping 31 July 2021		More Info & Links 29 February 2012
					LSD Shootout 7 January 2016		When Battery Testing Goes Bad – Consumer Magazine 20 June 2023		Battery Holder Shopping 28 July 2022

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