So what are the differences in the markings of cylindrical li-ion battery cells, e.g.:
18650
18500
16340 (aka RCR123)
16650
14500
26650
Protected
Bare
e.t.c
?
Well, the first two digits indicate the width, and the next two digits indicate the length of the battery in mm. For example, for the popular 18650 cell, this means that its width (circumference diameter) is approximately 18 and its length is 65 mm. And what does 0 mean? It doesn't matter, because so far there has always been a zero in this position, and it only reflects the method of calculating the length from the last three digits in decimal mm, not mm, as in the case of the width, i.e. in the case of a 18650 cell, we have: 650/10 = 65mm . It is important, however, whether the markings contain the word Protected , because the cells described in this way are usually 2.5-3mm longer and 0.5-0.6mm wider than those encoded in the markings of all the batteries mentioned above. The reason for this is the soldering of an external protection system to the bottom of the cell. Cells without protection may not have additional markings, or they are called "bare", "unprotected" or "flat top".
Warning to buyers of these cells :
You can easily cut yourself on low-quality cells, which are plentiful and often sold second-hand, so it's important to buy proven ones and not save on it. Unfortunately, the source from which we bought good cells for a reasonable price has run out, but we can at least recommend an inexpensive manufacturer on Aliexpress, whose 18650 cells should be of good quality:
Link to this product on AliExpress
And similarly, 26650 cells from the same manufacturer:
Link to CELL 26650 on AliExpress
Can I charge very different types of cells on one charger?
If we want one charger that can handle very different cell sizes and chemical types, we need this charger:
LINK TO THIS CHARGER ON ALIEPRESS
More on the sizes of these and other accumulators and batteries:
