The fact that it works with DexterOS is important. This tells us that your basic hardware is OK and that any issues you have are external to that.
DexterOS creates and configures its own “private” network and broadcasts as a “server” on that network. Ergo, everything is well known, defined, and encapsulated.
If I were doing this, I’d skip the rest of the Dexter software and go direct to the most general, plain-vanilla version of the Pi Foundation’s Raspbian software, (located at https://www.raspberrypi.org/downloads/, download that, hook up the Pi to a keyboard, mouse and monitor, and start from there.
Try to determine if you can configure, attach, and use your Pi’s WiFi using plain-vanilla Raspbian.
- Use it like this for a while to make sure you’re not experiencing a heat build-up issue.
- Make sure you have adequate battery power. A low or unstable power source has been the source of much grief since the first Cro-Magnon man tried to build his first 'bot out of bones, sinew, and a wooden wind-up key.
- Check the connections to everything.
- Try your Pi stand-alone; that is, not connected to the GoPiGo board or anything else but a keyboard, mouse, monitor, USB power supply and possibly an Ethernet cable.
- If/when you do this, make sure that whatever power supply you are using can source a minimum of 2 amps at 5v.
Let us know what happens.