27A, A27, MN27 12V Battery Equivalents and Replacements
27A, A27, MN27 battery is a small, cylindrical, non-rechargeable battery commonly used in car alarms, remote controls, garage door openers, glucose, and blood pressure monitors, telecommunication devices, headsets, toys, etc.
According to the IEC standard, this battery label is 8LR732, since internally, it consists of 8 (eight) LR732 (or LR632) batteries connected in series.
Updated: January 26, 2023.
27A, A27, MN27 Battery Features and Specifications
The most common labels for this battery are "27A battery", "A27 battery", or "MN27 battery", but it is also commonly known as A27BP, G27A, GP27A, L828, etc.
27A, A27, and MN27 battery dimensions are 8.0 mm in diameter and 28.2 mm in length (0.315 x 1.110 inches), and it weighs around 4.0 - 4.5 grams.
Since it internally consists of 8 (eight) LR732 (sometimes LR632) alkaline batteries, the A27 battery features a nominal voltage of 12.0 volts, a nominal capacity of 20-28 mAh, and a cutoff voltage of 6.0-8.8 volts.
Actual capacity depends on the cutoff voltage of the device being powered by an A27 battery and can even be 25+ mAh.
For example, the Energizer A27 battery features a typical capacity of 27 mAh when being drained down to 6.0 volts using a 20 kΩ load at 21°C.
Also, when the same Energizer A27 battery is being drained using a 20 kΩ load at 21°C, its runtime depends on the cutoff voltage, which is given in the following chart:
|Cutoff Voltage||8.8 Volts||7.2 Volts||6.0 Volts|
|Runtime||49 hours||54 hours||55 hours|
Note: Energizer A27 battery datasheet may be downloaded from the Energizer Official Website in the form of the Energizer A27 Datasheet PDF file.
A27/MN27 battery is a relatively common battery manufactured by several reputable brands, and it shouldn't be a problem to find it in local hardware stores or online shops.
Since it is an alkaline battery, its storage/standby life is 3-4 years, sometimes even more.
A23 vs A27 Battery
A23 and A27 batteries are two very similar batteries, sharing similar dimensions and internal structures.
While the A27 battery features dimensions of 8.0 x 28.2 mm and internally consists of 8 (eight) LR632/LR732, the A23 battery features dimensions of 10.3 x 28.5 mm and internally consists of 8 (eight) LR932 batteries.
|A23 Battery||A27 Battery|
Both batteries feature a nominal voltage of 12 volts, but due to the larger internal volume, A23 features a larger capacity (on average, 50-60 mAh vs. 20-22 mAh).
Some devices that are intended to be powered by an A23 battery also feature a small plastic battery adapter, being able to hold an A27 battery in place of an A23 battery - this allows the user greater flexibility in finding the required battery replacement, but if the device is regularly used, A27 battery will be discharged much faster than A23 battery.
AAAA vs. A27 Battery
AAAA are small, cylindrical batteries featuring dimensions of 8.3 x 42.5 mm and a nominal voltage of 1.5 volts.
A27 batteries may fit the AAAA battery compartment regarding their diameter, but fortunately, they are too short to be used as a direct replacement due to the difference in length (42.5 vs. 28.2 mm).
We say "fortunately" since the voltage difference is huge (12V vs. 1.5V), and such a voltage difference may destroy the device intended to be used by the AAAA battery.
Note: Some devices, for example, many Pen LED flashlights, are being powered by 2 (two) AAAA batteries stacked one behind another for the battery pack featuring dimensions of 8.3 x 85 mm and a nominal voltage of 3.0 volts.
Stacking 3 (three) A27 batteries in the same battery compartment is physically possible since it creates a battery pack featuring dimensions of 8.0 x 84.6 mm, but with a nominal voltage of 36 volts! Such voltage difference will for sure destroy any Pen LED flashlight or any similar device intended to be powered by AAAA batteries.
For short, AAAA and A27 batteries are not compatible in any way.
A27 Battery Safety Issues
Just like any other small and shiny object, the A27 battery may get swallowed by a child or pet.
Modern batteries don't contain heavy metals like mercury and cadmium, but they are nonetheless dangerous, especially 12V batteries, which may cause heavy internal injuries and chemical burns due to electrolysis.
If the A27 battery gets swallowed, call the local emergency center immediately and act according to their instruction.
That is the reason why most brands package their A27/MN27 batteries using so-called "pets and kids safe packages," which are sometimes hard to open even by adults - but better safe than sorry...
A27, 27A, MN27 Batteries Frequently Asked Questions (FAQ)
Here are some of the most common Frequently Asked Questions (FAQ) about A27, 27A, and MN27 batteries, but other similar batteries as well.
Are 27A and A27 batteries the same?
Yes, 27A and A27 are the same batteries - 12V alkaline 28.2 x 8.0 mm batteries.
What is the equivalent of a 27A battery?
27A battery equivalents are usually labeled as "A27 battery" or "MN27 battery," but they can use other labels as well, including A27BP, G27A, GP27A, L828, 8LR728, etc.
Are 27A and A23 batteries the same? Can I use A23 batteries instead of A27?
No, 27A and A23 are not the same batteries. They are both 12V alkaline batteries, but they differ in size:
- 27A battery: 28.2 x 8.0 mm
- A23 battery: 28.5 x 10.8 mm
As such, one can't use A23 instead of A27, but A27 can be used instead of A23 with the use of a suitable battery adapter at the cost of lower capacity.
How long does a 27A battery last?
The shelf life of the 27A battery depends on the brand and storage temperature, but it can range between 2-5 years, rarely more.
How to test a 27A 12V battery?
The easiest way to test 27A 12V and other similar batteries is by using a digital multimeter - check the actual voltage of the battery.
If the voltage is ~12V, the battery is good. If the voltage is in the 10-12V range, the battery was used but still has a decent charge left.
If the battery is below 10V, and especially below 8V, the battery is almost fully discharged.
To find out the exact remaining charge, measure the output voltage and check the battery's datasheet.
Where to buy a 27A 12v battery?
27A 12V battery can be found at local hardware stores, office supplies stores, camera/video equipment stores, and of course, online shops.
Long Story Short: If your device is powered by A27/MN27 battery and You need a new one, go for the A27/MN27 battery of some reputable brand.
If you happen to find out a plastic battery adapter holding an A27 battery and, after checking the device's documentation, You find out that your device supports the use of both A27 and A23 batteries, consider getting a good A23 battery which has the nominal capacity 2-3 times larger than A27 battery.
Again, don't swap AAAA and A27 batteries; that is an accident waiting to happen ...