Buying Button Cells for Digital Calipers

It is well known that the electronic digital caliper is an extreme important high precision measuring instrument for any scale machine shop. The good news is that they come into the market with fairly low price. Below are some tips on buying the correct replacement button cells for the common units such as the $20 version sold by tresnainstrument.
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Typically, a silver oxide button cell, the SR44 size, aka 357, 11.6mm diameter by 5.4mm high is used for the digital caliper. Generally, it is difficult for us to find a genuine SR44 or 357 cell, however, the alkaline LR44, which is the same size button, and same nominal voltage, is easier for us to find. Moreover,this alkaline LR44 cell is put into toys, laser pointers, etc., and has gotten very cheap because they are made in China where the cost of materials and the labor is relatively low. But alkaline buttons have much less mAh capacity, and have a critical weakness when used in devices like digital calipers that quit working when battery voltage falls. Compared to silver oxide , alkaline cells quickly "droop" their voltage (they have a non-flat discharge curve). So do bear in mind that don't run calipers for very long time before the display fades from low voltage.

Be aware that most retailers don't know the difference between LR44 (alkaline) and SR44 (silver oxide) and act like they are interchangeable, when they aren't. As a matter of fact, they are the same size, and the same nominal voltage, and it won't damage your calipers to run them on an LR44, but you'll only get hours of runtime from an LR44 instead of days and days from an SR44.