A-Size Battery Equivalents and Replacements
A-size battery or A-cell battery is a cylindrical battery that is rarely used directly in tools and appliances, but as a part of custom battery packs, it can be found in toys, tools, electric bikes and scooters, and similar.
A-size battery comes in various chemistries, featuring different terminal types, leading to some confusion. Also, batteries of similar sizes, like 2/3A, 4/3A, and similar, are also very popular.
A-Size Battery Dimensions and Features
A-size battery is a cylindrical battery featuring physical dimensions of (D x H) 17 x 50 mm (0.67 x 1.97 inches), while the weight depends on the exact battery chemistry and model.
A-size batteries may come with different battery terminals, including flat-top, button-top, and with different soldering tabs.
If You plan on making a custom battery pack using A-size batteries, always use batteries with factory soldered tabs - soldering the soldering tabs onto the battery at home may easily damage any battery, not just A-size batteries.
Non-rechargeable A-size batteries are rare and are not used often. Carbon-zinc A-size battery is also labeled as R23 battery, while alkaline A-size battery is labeled as LR23 battery.
Note: Don't confuse alkaline LR23 A-size battery with 12V LRV08 battery which is often also labeled as LR23 battery.
The nominal voltage of carbon-zinc and alkaline A-size battery is 1.5 volts, while capacity depends on the chemistry, battery age, discharge rate, and similar.
Non-rechargeable 17500 Lithium-Thionyl Chloride (Li-SOCl2) batteries feature nominal voltage of 3.6 volts, nominal capacity of ~3600 mAh, very low self-discharge rate (<1% annually) and are used in industrial, medical, security, backup, and similar applications.
Personally, if You are looking for an A-size battery, You are probably looking for a rechargeable A-size battery.
Rechargeable A-Size Batteries
Rechargeable A-size batteries are commonly Nickel Cadmium, Nickel Metal-Hydride, and Lithium-ion batteries.
Nickel Cadmium (NiCd) A-size batteries feature nominal voltage of 1.2 volts, nominal capacity of ~1400 mAh, and weigh 32-35 grams.
NiCd A-size batteries suffer from a strong memory effect, have a relatively large self-discharge rate, don't support a very large number of charging/discharging cycles and they contain Cadmium (far from being environment-friendly metal), and must be properly recycled.
On the other hand, NiCd batteries are able to provide extra strong currents and are still used for high-current applications. Nonetheless, NiCd batteries are being phased out by Nickel Metal-Hydride batteries even in high-drain applications.
Nickel Metal-Hydride (NiMH) A-size batteries feature a nominal voltage of 1.2 volts, nominal capacity 2500-3000 mAh, and weigh 35-40 grams.
When compared with older NiCd batteries, NiMH batteries feature larger capacity, have very low memory effect (if any in the latest NiMH batteries), support a larger number of charging/discharging cycles (when used properly and when charged with proper battery chargers), they are environment friendly, but they should also be recycled after use.
Note: while most manufacturers offer multi-drain NiMH A-size batteries, for cordless tools and similar high-current applications one should choose high-drain NiMH A-size batteries, even though such batteries have smaller capacity when compared with multi-drain and low-drain NiMH A-size batteries.
Lithium-ion A-size batteries are commonly labeled as 17500 batteries, they feature a nominal voltage of 3.6-3.7 volts and a nominal capacity of ~1100 mAh.
17500 batteries support up to 500 charging/discharging cycles, don't suffer from memory effect, have very low self-discharge rate, some high-drain models can provide very large currents (20C+ Amps), etc.
However, just like low-drain NiMH batteries, low-drain 17500 batteries should not be used for high-drain applications, since such use can ruin the battery quickly.
2/3A Battery vs A-Size Battery
As its label suggests, the 2/3A battery is similar to the A-size battery, except it is shorter and features physical dimensions of (DxH) 17.0 x 33.3 mm.
As such, 2/3A battery features a smaller capacity than the A-size battery, but due to the smaller size, it can fit smaller battery compartments.
2/3A battery is very popular for making custom battery packs and is used with and without soldering tabs.
2/3A size battery is a very popular battery:
- non-rechargeable CR123A lithium 3.0 volts battery features physical dimensions of 17.0 x 34.5 mm and is commonly used in EDC and backup devices where a strong battery with a low self-discharge rate is required.
- rechargeable 2/3A size batteries are often labeled as 17330 or 17335 batteries and are used for flashlights, toys, but also for battery packs intended for cordless tools and appliances.
4/3A Battery vs A-Size Battery
4/3A batteries feature physical dimensions of 17.0 x 66.7 mm and are used for making larger and stronger battery packs.
Rechargeable lithium 4/3A batteries are known as 17670 and usually may fit battery compartments intended for larger 18650 batteries. However, due to the larger volume, if You are looking for a 18650 battery, go for a 18650 battery.
NiCd and NiMH 4/3A batteries are still very common for both industrial applications, but also for making custom battery packs.
Long Story Short: If You are looking for an A-size battery, go for the battery of the same chemistry with the same or preferably better features like capacity, drain current, shelf-life, and similar:
- non-rechargeable A-size batteries carbon-zinc and alkaline batteries are very rare and if You are looking for them, check original batteries again.
- non-rechargeable 17500 Lithium-Thionyl Chloride (Li-SOCl2) batteries pack a lot of energy in a small package, and with their very low-self discharge rate are used in many EDC and backup systems and devices.
- rechargeable NiCd and NiMH A-size batteries are often used for battery packs used in toys, electric tools, and even scooters and some bikes. If You are looking for batteries with soldering tabs, go for such batteries and DON'T even try to solder tabs at home.
- rechargeable lithium A-size batteries (17500 batteries) support a large number of charging cycles and are used in devices that are often used, like flashlights, toys, tools, and similar.
Whenever looking for new batteries, always choose according to your own needs and requirements.