HTC Rapid Charge 2.0 overheating battery Since a few days ago I am charging my HTC One M8 using the HTC Rapid Charge 2.0  charger. It does indeed charge fast, but I have noticed that the battery gets really hot. After installing the DU Battery Saver, I can see that during charging the battery temperature gets up to 45C and even the app is notifying me that the battery is overheating.


Is this normal? 
Will I have long term problems with the battery by using this fast charger?
Excessive Heating of battery is a typical, inescapable effect of using " fast or rapid " chargers. Reason behind this is the charging rate. Normal charging uses 0.5 to 0.8 C (C is the charge rate) whereas fast charging uses anything between 1 to 3C. In simple words, this is pushing more current to charge faster. Heat produced is related to Power and governed by the equation 

Power = I² * R where I is current. 

So increase in current has a significant effect on increase in power (being proportional to square of current) , therefore heating, and the same is being reported by your app

Yes, it does have adverse effects:


In Short term: meaning when you charge and use, the Battery delivers less performance (another way of putting it is what charges faster Will also drain faster)
Long Term the battery life is reduced


Refer to my answer here for detailed technical explanation and a graph showing adverse effects How does fast charger work?

Edit: A helpful note on heat increase while charging from All about Battery Chargers


  Li-ion should not rise more than 10ºC (18ºF) above ambient when reaching full charge.