So, a solder connection to the cell(s) can work fine and be reliable? That’s what I needed to know. Thanks guys! RBD, thanks for the tip about cooling the cells with a wet towel. And thanks SawMaster for the tip about using needle-nose pliers for heat-sinking.
SawMaster, I would have bought the cells tabbed if I could, but I wanted the highest capacity, and these don’t have tabs. Maybe, if I’d researched a bit more I could have found them with tabs, but I was also trying to avoid fakes if possible, so I was limited in where I would buy from. I have a hard time trusting Chinese retailers to sell me genuine cells, after all the horror stories I’ve seen on BLF. The cells I bought were Panasonic 2040mAH NCR18500A recommended by Werner in this thread. If you know where I can get those same cells with tabs, I’d love to know it. If this works out, I may get another set of 15 and do it again.