Battery Sizes Decoded: Your Complete Guide to Powering Devices

Batteries are the backbone of our gadgets, from remote controls to high-tech medical devices, but their myriad sizes can be daunting. Ever puzzled over why AA batteries are everywhere while CR123A or Sub-C are niche? Each battery size is tailored for specific applications, balancing power, capacity, and dimensions. This guide explores all major battery sizes, their measurements, uses, and chemistries, complete with a comparison chart to simplify your choices. Let’s power up your knowledge!

Why Battery Sizes Matter

Battery sizes determine more than just fit—they dictate voltage, capacity, and performance. Standardized by the American National Standards Institute (ANSI), sizes like AAA, C, or 9V ensure global compatibility. Whether you’re powering a flashlight or a critical sensor, choosing the right size is key. Below, we dive into each size, their dimensions, and their roles in everyday and specialized devices.

Overview of Battery Sizes

Battery sizes range from tiny cylindrical cells like CR2 to hefty D batteries and rectangular 9V or CR-V3. They come in various chemistries—alkaline, lithium, NiMH, and NiCd—each suited to specific needs. Standard sizes (AAA, AA, C, D) are common in household devices, while specialty sizes (CR123A, Sub-C) power niche applications. Let’s explore each category.

Common Cylindrical Battery Sizes

AAA Batteries

Dimensions: 44.5 mm long, 10.5 mm diameter
AAA batteries are small but versatile, delivering 1.5V (alkaline) or 1.2V (NiMH) with capacities of 800–1200 mAh (alkaline) or 600–1000 mAh (NiMH). They power low-drain devices like remote controls, wireless mice, and small toys. Their compact size suits slim electronics, but their lower capacity limits use in high-drain applications.

AA Batteries

Dimensions: 50.5 mm long, 14.5 mm diameter
AA batteries are the most common, delivering 1.5V (alkaline) or 1.2V (NiMH) with 1800–3000 mAh (alkaline) or 1500–2800 mAh (NiMH). Used in flashlights, toys, and cameras, their availability and versatility make them a household favorite. Rechargeable NiMH AAs excel in high-drain devices like game controllers.

C Batteries

Dimensions: 50 mm long, 26 mm diameter
C batteries provide 1.5V (alkaline) or 1.2V (NiMH) with 6000–8000 mAh (alkaline) or 4000–6000 mAh (NiMH). They power medium-drain devices like flashlights, portable speakers, and toys. Larger than AA, they offer more capacity but are less common in modern compact gadgets.

D Batteries

Dimensions: 61.5 mm long, 33 mm diameter
D batteries, the largest standard cylindrical size, deliver 1.5V (alkaline) or 1.2V (NiMH) with 12,000–20,000 mAh (alkaline) or 8000–12,000 mAh (NiMH). They power high-drain devices like boomboxes, large flashlights, and emergency radios, ideal for long runtime but bulky for portable electronics.

Specialty Cylindrical Battery Sizes

½ AA Batteries (CR14250)

Dimensions: 25 mm long, 14.5 mm diameter
½ AA batteries deliver 3.0V (lithium) or 1.2V (NiMH) with 600–1200 mAh. Used in medical devices, IoT sensors, and compact electronics, their small size and long shelf life (up to 10 years for lithium) make them perfect for low-drain, critical applications.

2/3 AA Batteries (ER14335)

Dimensions: 30 mm long, 14.5 mm diameter
2/3 AA batteries provide 3.0V (lithium) or 1.2V (NiMH) with 400–1100 mAh. They power digital cameras, GPS trackers, and wireless sensors, offering a balance of size and capacity for high-tech devices.

½ C Batteries (CR17335)

Dimensions: 26 mm long, 17 mm diameter
½ C batteries deliver 3.0V (lithium) or 1.2V (NiMH) with 1200–3000 mAh. They’re used in industrial sensors, medical equipment, and backup systems, providing reliable power in compact designs, with lithium versions excelling in extreme temperatures.

2/3 C Batteries

Dimensions: 34 mm long, 26 mm diameter
2/3 C batteries offer 3.0V (lithium) or 1.2V (NiMH) with 1800–4000 mAh. They power robotics, specialty tools, and medical devices, balancing capacity and size for high-drain applications.

Sub-C Batteries

Dimensions: 43 mm long, 23 mm diameter
Sub-C batteries, primarily NiMH or NiCd, deliver 1.2V with 1200–3000 mAh. Rechargeable and designed for high-drain devices like power tools and RC cars, they’re favored by hobbyists and professionals for durability.

4/5 Sub-C Batteries

Dimensions: 34 mm long, 23 mm diameter
4/5 Sub-C batteries provide 1.2V (NiMH or NiCd) with 1000–2000 mAh. They power RC vehicles, flashlights, and portable electronics, offering high discharge in a compact form.

½ D Batteries (CR34615)

Dimensions: 37 mm long, 33 mm diameter
½ D batteries deliver 3.0V (lithium) or 1.2V (NiMH) with 2000–5000 mAh. Used in industrial equipment, medical devices, and backup systems, they provide high capacity in a smaller package than standard D batteries.

Rectangular Battery Sizes

9 Volt Batteries

Dimensions: 48.5 mm long, 26.5 mm wide, 17 mm thick
9V batteries, with snap-on terminals, deliver 9.0V (alkaline or lithium) or 8.4V (NiMH) with 500–1200 mAh (alkaline/lithium) or 600–1000 mAh (NiMH). They power smoke detectors, guitar pedals, and medical devices, offering high voltage in a compact form.

2CR5 Batteries

Dimensions: 34 mm long, 17 mm wide, 45 mm tall
2CR5 batteries, lithium-based, deliver 6.0V with 1500 mAh. Used in professional cameras, medical equipment, and industrial sensors, they provide high voltage and long shelf life in a rectangular package.

CR-V3 Batteries

Dimensions: 52 mm long, 28 mm wide, 14 mm thick
CR-V3 batteries deliver 3.0V (lithium) or 3.7V (rechargeable) with 3000 mAh. They power digital cameras, medical devices, and flash units, offering high capacity in a compact, rectangular design.

Lithium Specialty Batteries

CR123A Batteries

Dimensions: 34 mm long, 17 mm diameter
CR123A batteries deliver 3.0V (lithium) with 1300–1500 mAh. Used in digital cameras, tactical flashlights, and security systems, they offer long shelf life and reliability in extreme conditions.

CR2 Batteries

Dimensions: 27 mm long, 15 mm diameter
CR2 batteries provide 3.0V (lithium) with 800–1000 mAh. They power compact cameras, laser pointers, and medical devices, ideal for precision applications requiring small size.

Battery Chemistries: Understanding the Options

Battery sizes come in various chemistries, each with unique traits:

• Alkaline: Affordable, single-use, 1.5V, 5–7 year shelf life. Common in AA, AAA, C, D, 9V.
• Lithium: High voltage (3.0V–6.0V), up to 10-year shelf life, ideal for CR123A, CR2, 2CR5, CR-V3, and fractional sizes.
• NiMH: Rechargeable, 1.2V, 500–1000 charge cycles, eco-friendly, used in AA, AAA, Sub-C, and fractional sizes.
• NiCd: Rechargeable, 1.2V, durable but contains cadmium, used in Sub-C and 4/5 Sub-C.

Comparison Chart: Battery Sizes at a Glance

Battery Size	Dimensions (mm)	Voltage (V)	Capacity (mAh)	Common Uses
AAA	44.5 x 10.5	1.5 (Alkaline), 1.2 (NiMH)	800–1200 (Alkaline), 600–1000 (NiMH)	Remotes, Toys, Mice
AA	50.5 x 14.5	1.5 (Alkaline), 1.2 (NiMH)	1800–3000 (Alkaline), 1500–2800 (NiMH)	Flashlights, Toys, Cameras
C	50 x 26	1.5 (Alkaline), 1.2 (NiMH)	6000–8000 (Alkaline), 4000–6000 (NiMH)	Flashlights, Speakers
D	61.5 x 33	1.5 (Alkaline), 1.2 (NiMH)	12,000–20,000 (Alkaline), 8000–12,000 (NiMH)	Boomboxes, Radios
½ AA (CR14250)	25 x 14.5	3.0 (Lithium), 1.2 (NiMH)	600–1200	Medical, Sensors
2/3 AA (ER14335)	30 x 14.5	3.0 (Lithium), 1.2 (NiMH)	400–1100	Cameras, GPS
½ C (CR17335)	26 x 17	3.0 (Lithium), 1.2 (NiMH)	1200–3000	Sensors, Medical
2/3 C	34 x 26	3.0 (Lithium), 1.2 (NiMH)	1800–4000	Robotics, Tools
Sub-C	43 x 23	1.2 (NiMH/NiCd)	1200–3000	Power Tools, RC Cars
4/5 Sub-C	34 x 23	1.2 (NiMH/NiCd)	1000–2000	RC Vehicles, Flashlights
½ D (CR34615)	37 x 33	3.0 (Lithium), 1.2 (NiMH)	2000–5000	Industrial, Medical
9V	48.5 x 26.5 x 17	9.0 (Alkaline/Lithium), 8.4 (NiMH)	500–1200 (Alkaline/Lithium), 600–1000 (NiMH)	Smoke Detectors, Pedals
CR123A	34 x 17	3.0 (Lithium)	1300–1500	Cameras, Flashlights
CR2	27 x 15	3.0 (Lithium)	800–1000	Cameras, Laser Pointers
2CR5	34 x 17 x 45	6.0 (Lithium)	1500	Cameras, Medical
CR-V3	52 x 28 x 14	3.0 (Lithium)	3000	Cameras, Medical