Apple has confirmed that there are certain Apple iPhone 6s and iPhone 6s Plus devices may have a power issue due to a component defect. The company yet to disclose which part and what’s the actual reason for it.
This issue only affects some devices that were manufactured between October 2018 to August 2019 within a limited serial number range.
You may check whether your iPhone 6s or iPhone 6s Plus is eligible for free repair via serial number checker on their website: Apple Malaysia
You can find your Apple product serial number HERE