I tested Panasonic NCR18650B cells provided by Randy. Randy runs the Energia Dynamics shop on eBay, where he sells this particular variety of 18650 cell, along with others he imports. I did these tests to help him verify the quality of shipments from his suppliers.
Randy provided two cells from a matched lot, and another cell from an alternate supplier.
I’m not happy with the variability in the test results here. You can see that the starting voltages vary quite a bit, probably due to variations in temperature, and also time between charge and discharge of the cell. You can also see that the capacities for Cell 2 under 1A discharge are fairly different. I’m also missing capacity data for some runs of some of the cells due to quirks in the testing software.
I’ve made some improvements to my testing procedures since doing these tests, and I have more improvements I want to make. I’ll rerun the tests on these cells at least once in the future and update this page once I do. Until then, I feel comfortable saying that the results of these tests don’t given any reason to think these cells are anything other than high quality cells.