Please, my phone iphone 6s purchased just that he loses battery charge horrendously

What troubleshooting have you tried? Did you restore this phone from a backup of an older phone? I have an iPhone 6s, 64GB version on iOS 9.0.2, and I must say that this is the best battery I've had on any iPhone I've ever owned. I consider myself a moderate to heavy user and I rarely use more than about 2.1% of battery per hour, under the heavy usage. I would say there is probably a process stuck or there was corrupt data if you restored from a backup. If you go to Setting>Battery, what is using the majority of your battery? The culprits are listed in order, highest first. That will help you identify and troubleshoot the problem app or apps. User troubleshooting includes restart, reset, restore from backup, restore as new. Test after each step. If you get to restore as new, test this without adding any additional content. If you still see this rapid battery drain, then make an appointment at the Genius Bar of the nearest Apple Store to have the device examined.

Restart your iPhone, iPad, or iPod touch - Apple Support

Restore your device from an iCloud or iTunes backup - Apple Support

Use iTunes to restore your iPhone, iPad, or iPod to factory settings - Apple Support

Make an appointment at the nearest Apple store to have your iPhone evaluated.

Once the diagnostics are complete, the staff will explain your options.

Make a Genius Bar Reservation

http://www.apple.com/retail/geniusbar/