Do you know the difference between a 123 and a 123a battery? Most people don’t, but they assume there must be a difference. Why would they have different names, after all?
In reality, it isn’t that simple. This article will take you through the differences and answer any questions you have about how to use these two types of batteries. So, what is the difference between a 123 and a 123a battery?
What is a 123 Battery?
A 123 battery is a small 3 volt lithium battery with a general power capacity between 1,500 mAh (milliampere hour) and 2,500mAh. A milliampere hour measures the amount of current that flows from the battery to the device it is powering each hour. In most cases, a higher mAh value means that the battery lasts longer. A typical 123 battery can charge a device drawing 100 milliamperes for roughly 30 hours.
123 batteries are very common and they are used in all sorts of small appliances around the home like alarm clocks or flashlights, for example.
What is a 123a Battery?
A 123a battery is also a 3 volt lithium battery and it has roughly the same power capacity as a 123 battery. So, you will be able to power a device for around the same amount of time that you would with a 123 battery.
123a batteries are often used in small devices that draw a lot of power, like cameras or bright LED torches, for example.
Are 123 Batteries the Same as 123a Batteries?
Based on those two descriptions, you might assume that 123 batteries are exactly the same as 123a batteries, but that isn’t quite true. The two are incredibly similar but there are tiny differences.
The main difference between the two types of battery is the size. A 123 battery is 34mm long and 16.5mm wide, while a 123a battery is 34.4mm long and 17mm wide. A 123 battery weighs in at 16.5g while a 123a battery is slightly lighter at 16g. So, as you can see, there is a difference in the size of the batteries but it is very minimal.
Beyond that, the batteries are basically the same. They have the same voltage and mAh and will last the same amount of time if put in the same device. They also have all of the same safety features, etc.
Can I Use a 123 Battery in a 123a Battery Compartment? 
Some people say that the batteries are essentially the same and can be used interchangeably, which is often true, but that should be taken with a pinch of salt. If they are standard non-rechargeable batteries, you shouldn’t have any problem putting a 123 battery in a 123a battery compartment. However, rechargeable batteries can sometimes have slightly different voltages and this can cause issues.
Certain devices may only work if you use a specific battery (although not that common) so always check before switching batteries.
Can I Use a 123a Battery in a 123 Battery Compartment?
The same applies here. For simple devices like flashlights, you can get away with putting a normal 123a battery in a 123 compartment, but it’s best to double check with rechargeable batteries that they are the same voltage before using them. Exceeding the recommended voltage could damage the appliance.
It also depends on the size of the compartment. In some cases, there may not be enough additional space to fit the slightly larger 123a battery into the 123 compartment. Overall, it is probably best to stick to the recommended battery just in case, but it shouldn’t cause any major disasters if you use them interchangeably.
What Does CR Mean Before the Numbers?
Often, you will see the batteries called CR123 and CR123a, but what does the CR mean?
The CR prefix is used to show that the batteries are lithium-based. The C denotes lithium and the R signifies that it is a round battery. The numbers after the CR then show the size of the battery. It is essentially up to the manufacturers to decide if they want to use 123 or 123a, and some companies use a different notation system altogether.
Do 123 and 123a Batteries Have the Same Voltage?
Yes, both 123 and 123a batteries are 3 volts. This is the maximum voltage output and batteries will generally put out between 2 and 2.5 volts.
Do 123 and 123a Batteries Have the Same Shelf Life?
Yes, both batteries have a shelf life of roughly 10 years, as long as they are stored at a reasonable temperature and they don’t leak.
Are 123 and 123a Batteries Both Lithium Batteries?
Yes, both batteries use lithium-based salt and lithium and manganese oxide. The chemical system in both batteries works in exactly the same way.
What are Common Uses for 123 and 123a Batteries?
123 and 123a batteries are used for smaller devices that draw a lot of power or require a long life span because they are heavy-duty batteries, especially compared with standard AA or AAA. Common uses include:
- Flashlights
- Cameras
- Alarm clocks
- Smoke detectors
- Wireless alarm systems
- Home automation devices
- Military equipment
What are the Best 123 and 123a Batteries?
There are lots of different 123 and 123a batteries available. These are some of the best ones.
1. SureFire 72 Pack 123A Lithium Batteries
If you need batteries for a high powered flashlight, the SureFire 123A Lithium Batteries are the perfect choice. These high-performance batteries have a wide heat tolerance, so they can be used for extended periods without issues. This also makes them suitable for use by the emergency services. You get great value for the large pack of 72 batteries too, so you can stock up.
2. Amazon Basics Lithium CR123a 3 Volt Battery
You don’t always need expensive branded batteries if you are just using it for a camera or a basic flashlight for use around the home. These Amazon Basics CR123a batteries are ideal if you need an affordable but still reliable battery. The pack of 6 is perfectly fine for everyday devices and they’re cheaper than a lot of other batteries you will find.
3. Duracell 123 Ultra High-Power Lithium Battery
Duracell has a reputation for being one of the most reliable battery providers out there, and if you have devices that get a lot of use, you should consider investing in their 123 Ultra-High Power Lithium Battery instead of a cheaper option. They give you excellent performance and last a long time, so they’re perfect for important devices like smoke detectors too.
4. RAYOVAC Lithium Photo 123A Battery
The RAYOVAC Lithium Photo 123A Battery is specifically designed for use in cameras, but they can be used in other devices too. They’re very effective in devices like cameras and smoke detectors, but they can be hit and miss when used in home security systems, so consider another option if that is what you need.
5. Energizer 123 Batteries (Lithium CR123A)
Energizer is another well-known brand that has a reputation for high-performance batteries, and their 123 Batteries are no exception. They are reliable and long lasting, and they have a power output of 1500mAh. They’re available in packs of 2, 6, or 12, so you don’t have to buy more than you need if you only use them occasionally.
What Are Some Other Names You Can Find 123 and 123a Batteries in?
The naming system for batteries is flexible, which is how you end up with 123 and 123a batteries in the first place. You will often see them called different things, but they are still the same batteries. Other names include:
- CR123 and CR123a
- DL123a (Duracell Batteries)
- EL123 and EL123a
- SF123 and SF123a
Are 123 and 123a Batteries Rechargeable?
Yes, they can be. There are non-rechargeable and rechargeable options available for 123 and 123a batteries.
Are C Batteries the Same as 123 Batteries?
No, a C battery is a different size to a 123 or 123a battery and it is also 1.5 volts rather than 3 volts. If you try to use them interchangeably, they will not fit and even if they did, the voltage difference would stop the device from working properly. C batteries are sometimes used in similar devices, like cameras or flashlights, but they are a completely different battery.
The Verdict – Are 123 and 123a Batteries Different?
The short answer is, no, not really. In most cases, they can be used in the same devices and you get the same power output. There is a small difference in the size but it is usually negligible. There are a few devices that will not allow you to use both 123 and 123a batteries but basically, the difference is just in the way that the manufacturer decides to name the batteries.
Read our related battery article:
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- Can You Use a 40v Battery in a 20v Tool?
- What Is the Difference Between a 2.0Ah Battery and a 4.0Ah Battery?
Jamie is the Founder of My Home Dwelling. He is a homeowner and enjoys sharing his homeowner tips with others. He has real estate experience working as a new home construction Realtor. Jamie has worked on numerous residential construction sites helping with interior and exterior renovations. He loves refinishing furniture, DIY home projects, and sharing his knowledge online.