This past weekend I had a chance to demo the nodeLED at the MakerFaire Hackaday meetup and at OSH Park’s Bring-A-Hack. I wasn’t sure if I would have power, so I decided to use a 7.4V LiPo I had from an old project. It wouldn’t be full brightness but enough to demo. During the first meetup, I left it running on the table but after some time passed, I noticed it was off and the regulator was quite toasty. I quickly unplugged it. Dead battery was my initial reaction. Especially after I had plugged it in again, the esp8266 LED seemed to flutter and go out. But by using the handy USB Tester with the DC Tester, I could tell the battery wasn’t dead because it dropped straight to <1v when plugged into the nodeLED. So something else was going on if the battery cutoff was triggering. Also, I didn’t get to demo it at the Bring-A-Hack! Bummer!
I can’t leave a problem unsolved so upon arriving home from the weekend away, I tested the nodeLED with a 12v wall-wart. Um yeah, I about burned myself on the regulator! I should've known better, especially if the battery was cutting out. I also noticed if I plugged the nodeMCU into my computer, the onboard user LED would only illuminate very dimly, also becoming a bit toasty.
Following up a couple of days later, I did some more testing and I could tell that the nodeLED itself is fine; the regulator is healthy. The problem lies with the nodeMCU, which is very strange. I plan on investigating the cause further, but for now, and in the interest of time, I will have to use another nodeMCU. Good thing I have extras!