Why am I always partially charging my iphone 5?

I have the app Battery Doctor and it says I partially charge my iPhone all the time… It says I will charge it for 3 minutes then unplug the iPhone. I only charge my phone at night so I never unplug it until the morning. Does anybody know what's going on?

Maybe once it's charged, it trickle charges. The 3 minute charges might be reflecting that.

Because it's an iPhone