Today I was training a person how to fly a Vision Plus and with approximately 35% battery life remaining in the first flight the machine glitched for a second and then it would not respond to any stick commands. We were not using my iPhone for that flight so I couldn't tell if a message would have been given. I tried the failsafe switch, but it didn't respond. I then turned the controller off thinking that would activate the fly home mode, but it didn't make a difference either. The quad stayed hovering where it first glitched until the battery got so low that it slowly came down for a landing. I was fortunate that the problem happened in an open area...the landing was excellent with no damage. I then put another freshly charged battery in and activated my phone so I could check for any messages if it happened again. Everything went well with the second flight for the first 3 minutes or so, then at 77% battery life remaining, a battery error was indicated on my phone screen. I still had control of the aircraft and brought it back to where I took off and had an uneventful landing. I'm wondering if anyone very familiar with the Vision Plus has an idea what the problem may be. The only thing I have done in checking it out is put it on the assistance software to check for any abnormalities. Everything look fine from the computer software. I welcome any thoughts or advice. Thanks!