Thank you, all clear now, so M5.shutdown(600) will run again the entire setup. Great!

Now M5.shutdown(600) it is run actually every 9 minutes and M5.shutdown(3600*11) every 2 and almost a half hour, not 11 hours.

In order to avoid charging problems I use:

if (voltage<4150) {
M5.shutdown(shutdownDuration);
}

otherwise it restarts every 5 seconds when charging. Is there any other solution when charging?
The battery only charges to max 4100 and is dead at 3410: just bought a new M5Paper a week ago.

float voltage = M5.getBatteryVoltage();

@felmue If I use esp_deep_sleep_start(); with canvas.drawJpgUrl() it restarts every 5 seconds. Works with light.

@volker 6 days on deep.sleep. How about light.sleep? I just bought mine, any advice? I only want to display a picture via internet..