Battery draining rapidly

I have an iPhone 7+ and ever since I did the iOS update to 11, and the subsequent updates, my battery has been draining much faster than normal. With normal use, my battery used to last the whole day, now, it's drains to less than 10% by noon. Is there a glitch causing battery issues with these updates? I've read the battery maximization articles and a few others but none of those seem applicable in this case. Help!