Lightbulb Using ZTE blade without battery and connected to a charger?

So I shifted to a new phone long ago buy I still have this phone with me and I have no use for it. I just found that I can use this phone without battery while connected to a charger.

Now I am planning to use this phone as a torrent downloader. Which will be 'on' 24x7, I think keeping it plugged in the whole time will harm the battery.

So my question is, will I damage my phone if I keep it on 24x7 without a battery, connected to a charger? Because it seems the output of charger is too high compared to the battery, which might harm the phone in long run.