Well as someone who went from a 64GB iPhone 5S to a 128GB iPhone 6S- I can assure you that the 6S has way longer/better battery life. So, your iPhone's capicity is not your only mistake -- there may be other "typos" -- for instance you may be using your new iPhone twice as much as the old one -- that would certainly hit the battery
Dude you have "wrong forum" typo lol, you are nearly ironic!