Does using a portable device (phone, tablet) while charging reduce battery lifespan?

I got a new mobile phone recently, and the employee at the T-Mobile store told me that you shouldn’t use the device while it is charging, as that will reduce the life of the battery. Any truth to this? I found 1 or 2 references to this with Google, but nothing that seemed too trustworthy.

I wouldn’t expect to have any impact on the long term battery life.

I use my phones while they are on the charger all the time. It will effect how quickly the device charges, because you’re either draining the battery while it’s trying to charge, or your using some of the charge current to power the device.


I’ve an HP laptop and the battery gets very how when using while charging. So, rewording of the OP. Does getting the battery very hot impact the long term battery life?

Good question about the heat. I hang my phone in my car right off the AC vent, so when I’m listening to stuff from my phone in the car, it’s getting cooled by the AC. I wonder if that would offset any heat generated by it charging at the same time it is being used?

What I have been told on this (and I am not an expert in this myself):

The new generation of lithium ion batteries don’t have “memory” issues like the cordless phone batteries of the olden days; you don’t have to worry about full drain/full charge cycles. But they do have limited life spans, so the more you use them, the quicker their ability to hold a full charge diminishes.

Considering you can still by 2 year EWP on these things, I’d expect them to last 24 months with heavy usage. Provided you don’t have an iPhone, you can also always get cheapo replacements!

I know that battery memory is no longer an issue, the question is if:

  1. charge for one hour THEN use for one hour
  2. charge for one hour WHILE using for one hour
  3. charge for one hour WHILE using for one hour, WHILE in front of a cold AC vent

all degrade the lifespan of the battery at the exact same rate or not.

It’s all irrelevant.
You only have a 3-5 year lifespan on these batteries whether you use them or not. No matter how gingerly you treat them, they still are going to fail.

Yes, of course they will eventually fail no matter what. Nobody is claiming otherwise.

But for the two years or so I have the device, I would like a charge to last as long as possible.

Just let the smart controller do it’s job. That’s why all Lithium battery packs have one.
Micromanaging things is just going to make you crazy.

And, BTW, you are never going to get a definitive answer - there are too many unknowns.

Yes, heat will impact the long term battery life, particularly heat while the battery is charging and/or in use, and even more particularly when the battery is close to being fully charged. A lithium battery always prefers to be right around 40% charged - you will get longer life expectancy the longer your phone stays near that range.

Nope, all would be quite different, but there are also other factors you’re not considering, like state-of-charge and the rate of discharge.

Charging the battery generates heat, then depending on how much current you’re drawing from the CPU/electronics/radios, using the phone also generates heat. (So, doing something that was simultaneously CPU, display, and radio intensive, will produce considerable heat.) A hot car with no A/C would also be additional external heat if you’re not using the A/C vent to cool it.

Much more info and data, here:

Thanks for the info!