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?
  • 1
    Efficiency decreases from overheating.
    – Firelord
    Commented Aug 5, 2015 at 21:30
  • 1
    Makes sense, but is this supposed to happen when using this rapid charger?
    – Adrian
    Commented Aug 6, 2015 at 6:45

1 Answer 1


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.

  • That makes sense, thanks for the explanation. Let me rephrase my question then, are batteries "ready" for fast chargers? Do they have enough heating protection due to the faster charge rate? Should I only fast charge when really needed and use a regular charge in all other cases as to ensure a longer battery life?
    – Adrian
    Commented Jan 13, 2016 at 7:25
  • Honestly, nothing has changed in battery chemistry or build to accommodate "Fast charging". People want "fast everything" and it fits well with OEM strategy of "planned obsolescence" ( time to change your phone when battery dies is the message they sell). So yes use a fast charger only when you really need . If your phone comes only with a fast charger charge via battery pack. Happy battery life. If the answer meets your expectations, consider "accepting" please. It helps others also see value in the answer
    – beeshyams
    Commented Jan 13, 2016 at 7:53
  • FYI. You may like to see Quick Charging 3.0 explanation here android.stackexchange.com/a/138678/131553
    – beeshyams
    Commented Mar 3, 2016 at 3:48

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