I have the exact same problem posted here, the only difference is that I already had W10 on my phone, and I had updates, many restarting of the phone, and from now on, I loose 100% charge in 7 hours...(at night without doing nothing) and yes, it's a lumia 735. I didn't change anything on the phone, kept the same settings, and unless while updating, some of the settings were changed, I don't know what to do. It's a pain in the neck !
Simon
Simon