I am using a knockoff from amazon, OSOYOO Mini USB Nano V3.0 ATMEGA328P Module CH340G 5V 16M Micro-controller board for Arduino. I'm worried that is my problem. I have it running on a 12v power supply with a 9v backup. It runs fine when it is connected to the computer but when I unplug it it seems to just get "stuck" and doesn't loop through the code.
link to product- https://www.amazon.com/gp/product/B00UACD13Q/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1
I am wondering if maybe an external crystal will help.
Please let me know if there is any additional info you would like to know.
Before I get hell for the rip off arduino know that I have a couple purchased directly from the company. I very much appreciate the makers of arduino and I prefer to support them.