Headlights problems of the 2008 Mercedes Benz ML320

While driving the mercedes Ml320 at night the vehicle suddenly posted the following message "battery voltage is too low. Please start the engine. Otherwise, comand will shut off in 3 minutes. " the engine was running at this time and the vehicle was in motion. A short time later the headlights on the vehicle suddenly went out. I turned on the flashers and they also went out in a short time. The vehicle was parked and would not re-start. About 15 minutes went by and the vehicle was started and fully functional. No signs of codes or reduced lighting performance. Also, no signs or reduced battery perfomance was observed.