Why is my Xiaomi redmi 5 plus battery draining too fast

I had the same issue on my Redmi 5 Plus. Usually, it’s a mix of old battery plus heavy apps running in the background. Try checking which apps use the most battery in Settings → Battery, and consider disabling/limiting them. Also, turn off things like location, auto-sync, and Bluetooth when you don’t need them. If your phone is a few years old, the battery might just be worn out, and replacing it can make a big difference.