Mail Causing battery draining on iPhone iOS 11

Hello

I m using an iPhone 7 with iOS 11.2

I noticed , in the battery statistics , that mail shows 8 minutes of usage , 7 in background but it was responsible for the 23% of the battery usage in the last 25 hours.

This keeps happening every day.

I have 4 email accounts : 2 set on push , 2 on fetch every 30 minutes. Always had this 4 since the previous iPhones, but this problem started to show up with iOS 11 .

i don't want to set everything to manual......i wouldn't want to...