4SR44, 4LR44, PX28A, A544, 28A, K28A Battery Equivalents and Replacements
4SR44 or 4LR44 battery is a small cylindrical battery often used in dog collars, film cameras, small LED flashlights, car security systems, remote controls, toys and similar.
Common labels for this battery are 4SR44 or 4LR44, depending on the exact chemistry, but there are many other labels that may confuse the user, including PX28A, A544, 28A, K28A, K28L, V34PX, 476A, 4A76, 2CR1/3N, 2CR11108, etc.
Physical dimensions of the 4LR44/4SR44 batteries are: 25.2 mm in height and 13 mm in diameter (~0.992 x 0.518 inches), with their labels (4LR44 or 4SR44) describing its internal construction - four LR44 or SR44 batteries stacked vertically.
Thus, some manufacturers even deliver their devices powered by 4SR44 or 4LR44 batteries with the small plastic battery holder, allowing the use of single 4LR44/4SR44 batteries, or four LR44/SR44 batteries or even two CR11108 (CR1/3N, 2L76, 2LR44) batteries.
Note: four LR44/SR44 or two CR11108 or CR1/3N batteries stacked vertically feature diameter of 11.6 mm and height of 21.6 mm, thus requiring battery holder to fit 25.2x13 mm battery compartment.
Typical capacity of the 4LR44 alkaline battery is 130-170 mAh and around 150-200 mAh for 4SR44 battery, with the most important features given in the following chart:
|Nominal Voltage||6.0 volts||6.2 volts|
|End-Point Voltage||3.6 - 4.0 volts||3.6 - 4.8 volts|
|Notes||Voltage drops over time||Very constant voltage|
|Typical Labels||4SR44 (silver-oxide), 4LR44 (alkaline), PX28A, A544, K28A, K28L, V34PX, 28A, 476A, 4A76, 2CR1/3N, 2CR11108|
|Typical Capacity||130-170 mAh||150-200 mAh|
Typical labels of these 25.3x13 mm non-rechargeable batteries are 4SR44, 4LR44, PX28A, A544, K28A, K28L, V34PX, 28A, 476A, 4A76, 2CR1/3N, 2CR11108, but believe or not, there are other labels as well.
Generally 4LR44 is alkaline battery, 4SR44 is silver-oxide battery, while 2CR1/3N or 2CR11108 are typically non-rechargeable lithium batteries.
Fortunately, in order to sell their batteries, manufacturers write down several labels, often their own in-house label, and the battery's chemistry.
Capacity and cutoff voltage of 4LR44/4SR44 batteries depend on the drain current and on the device being powered by these batteries.
For example, Energizer A544 battery is alkaline battery consisting of four LR44 batteries connected in series, featuring metal jacket.
Their typical capacity is 178 mAh when being discharged over 30kΩ at 21°C down to 3.6 volts. While 178 mAh is excellent capacity of LR44 or 4LR44 battery, not every electronic device can operate with such low input voltage (most does, but if not sure, check the documenation, and if the cutoff voltage of your devices is 4.0 or more volts, go for silver-oxide 4SR44 battery).
Varta V28PX battery is high-drain silver-oxide 4SR44 battery, with nominal voltage of 6.2 volts and typical capacity of 145 mAh when being discharged using 20kΩ load at 20°C down to 3.6 volts.
Despite being silver-oxide battery, Varta V28PX features lower nominal capacity than alkaline Energizer A544 (145 vs 178 mAh), but drain current of the Varta V28PX is almost twice as strong as Energizer A544 current (310 vs 160 μA), despite having load 'just' 33% lighter (20 vs 30 kΩ), thanks to the higher voltage of the silver-oxide chemistry.
So, in this example, which one is better, alkaline Energizer A544 or silver-oxide Varta V28PX? Obviously, if you have to choose between these two models, for low-drain devices go for Energizer A544 and for high-drain devices, go for Varta V28PX battery.
Like all other similar batteries, 4LR44 and 4SR44 batteries feature on average 3-5 years shelf life, with some low-drain models used as motherboard batteries feature 5-7+ years shelf life.
Safety Issues: Although 4LR44/4SR44 batteries are not the smallest batteries on the market, kids and pets may try to swallow them. If that happens, call immediately emergency services (doctor, vet somebody else) and do as you are told - modern 4LR44/4SR44 batteries don't contain mercury, cadmium or similar heavy metal, but when swallowed they start electrolytic processes in human/animal body that can be rather dangerous.
Long Story Short: When looking for 4LR44/4SR44 battery equivalent/replacement, go for 4LR44/4SR44 battery from reputable brand and go for the most popular models with good reviews.
4LR44/4SR44 are rather common batteries, they are manufactured by most battery brands and are available around the world in various hardware stores and online shops.