Arduino freezes after running a while.

Hello. I am having some trouble with my code.
It is a system used to test start up current through eg. a start relay.

Code works fine - no problem the first couple of hours, then it hangs.

First i had written it with sprintf, but saw another post talking against it as it might be memory leak that makes it hang.

Now I have also added a watchdog timer, but it doesn’t save it, still hangs up after some hours and doesn’t start over again.

Have attached code.

_140918_LCD_startstop_relay_gsm.ino (10.5 KB)