I figured that the lightning cable was going bad, so I ordered a new cable, but it did not make a difference. Charging was still intermittent, so I ordered another lightning cable, but the problem persisted.
Although charging was intermittent, the iPhone would get fully charged eventually, so I left well enough alone. But well enough got worse the last few days and I had to do something.
I used a flashlight to look in the connector to see if there was an obvious problem. Instead of bare metal, I could see various shades of grey matter inside the connector! It was full of dirt.
I took a straight pin and used it to clean the connector. I couldn’t believe all the crud I pulled out of there! I worked at it for about a half hour until I could only see bare metal inside.
I then plugged in the lightning cable and the iPhone began charging immediately without interruption.
