When I bought my house, I bought a voltmeter (really a digital multimeter, or DMM) at Home Depot. It has served me pretty well except that it doesn’t measure current (amps), so I wound up buying a second one pretty cheaply at Amazon. The new one uses a 9V battery, but the one from Home Depot has two button cells in it. The LED display was getting pretty faint, and now it is almost impossible to read after I left it on all night recently. So I needed some batteries.
The size written on the cell is L1154. On Wikipedia, I learned that cells that start with C are lithium and cells that start with L are alkaline. Lithium cells are usually 3 volts while alkaline are 1.5 volts. There are also silver oxide cells that start with S. I looked online and found I should be able to get a pair of cells for less than $2. I visited Walgreen’s but they only had lithium and silver cells and none seemed to be the right size. Plus they were at least $4, sometimes just for one battery. I went to Walmart today and, while they had some L cells, they were still pretty expensive. I visited their outdoor section to look at flashlights and they had one that uses 3 357 size button cells (very similar looking to the batteries I needed) for $4.50, including the 3 batteries. Up front in the battery section, you could get a package of 3 357 cells for $5.50 and it didn’t even include a little flashlight. This just reinforced what I knew already, which is there is a huge markup on these batteries.
Next I went to Rite Aid where I was looking to use up a $4 store credit before it expires next week anyway. They had a selection of cells, but none of them were the right size either. And they were expensive.
When I got home I looked up Wikipedia’s article on battery sizes and discovered that the 357 size is the same as what I was looking for, the L1154. Wikipedia says the IEC name for this size is LR1154, where the L is for alkaline, the R is for round, the 11 is the diameter in mm, and 54 is the height in tenths of millimeters (so 5.4mm tall). So at least it is kind of sensible if that name is used, but other names can represent the same thing: SR44, AG13, SG13, LR44, LR154, A76, S76, 157, 303, 357, LR1154, SR1154, 1166A, 1107SO, and 1131SOP. Some of those are names for the same size in silver oxide. The silver oxide batteries are interchangeable with alkalines but last longer. They also cost more and that’s what you usually find at the drugstores.
I thought it would be good to have a note on my iPod with all the battery sizes, but then I realized I already have all of Wikipedia on there already. Actually I have all of Wikipedia but the pictures and tables and that information is in a table. But the latest version of Wikipedia Offline lets me pull the latest version of a page, including tables (which are rendered in Safari, and you have to bookmark the page for the new version to be saved permanently).
With this information, I went to Amazon to see if I could find some cheaper batteries. Pretty quickly I found a place selling 10 Maxell LR44 batteries for $2.26, including shipping! Done. I should have plenty now even though my electricity detector and my electronic calipers use the same size. If anybody wants any, let me know.