Does the magnet on my cover discharge my battery faster?

I Have the iphone 5s which had a cover whith a magent on it, which at the time my battery would last about a day.

My cover broke and i lost the magnetic part, at which time over a period of two weeks my battery was lasting me about two days.

I Have recently bought a new cover, same style as my old one, and i have noticed that my battery life has dropped again down to one day.

Over the period of not having the magnet, and over the time of have it i was using my phone at about the same amount of time, and using the same apps, each time.

thanks for any help given on resolving the issue.