MKRFOX1200 sleep board when using VIN port for power supply

Hi there
Hi

I have a MKRFOX1200 connected with 3x1,5v batteries to the green battery port - this one has send for over 6 months now - 1 time per hour.

Then I have build 3 other MKRFOX1200 boards - also with 3x1,5v batteries - but connected to VIN port, sending 1 time per hour. The good thing about using the VIN port is, the board output to ex sensors always will be 3V.

After 1 month the battery is done - I have found out, that the consumption increase when using the VIN port - that must mean, that I can't set the board to sleep.

Can anyone tell me - how I can use the VIN port and still have the board to go to totally sleep mode - so the consumption between sending is close to nothing.

I am using the #include <ArduinoLowPower.h> library - and the LowPower.deepSleep(10006060); command.

Thanks in advance.