why are my 18650 cells shorting?
After realizing lead acid batteries are sooo 1859, I decided to construct a battery pack out of 18650 cells. I soldered 4 in series on the top half of the cells. When I went to do the bottom half I found that touching the wire from one negative terminal of one cell to the positive of another cell it short circuited. At first I thought I had a bad cell so I checked all of them and they were all fine. I desoldered them and tried putting only 2 in series, same thing. The cells still put out ~3.7 so I don't see the problem. please help.