Start/stop automatic on the V40

This device can be switched off, but you have to do that every time you start. I would like to have it permanently away because I have had bad experiences with a replacement vehicle. I also do not believe in the big fuel saving effect. With each automatic. Restart is also used, therefore the V40 has a 2nd battery. I ask because I will soon get a new V40 (petrol, hand switch)