Generally speaking, it’s safe to use a phone while charging it with a power bank.
However, and here comes the disclaimer, it’s best not to do so if you can. First of all, using the mobile while it’s being charged by a power bank will lead to an increase of radiating heat. As you already noticed, when you’re actively using your smartphone, it tends to get hotter the more intensely you’re using it, such as in the example of playing a game. Similarly, the phone will get a bit hot when it’s being charged, even if it’s not used. This happens due to the transfer of energy from the charger/power bank to the phone battery. So if you’re both charging the phone with a power bank and using it at the same time, then these two heat-generating activities will overlap and the phone will get warmer than usual.
The extra heat does have some negative consequences. Although most of the time they’re negligible, you should still be aware of them:
Reduced charging efficiency
Extra heat leads to a reduced charging efficiency. This means that you’ll get less out of your power bank’s capacity than expected. The power bank will lose more energy in the process of charging your phone, so in the end, a smaller capacity will end up in your phone’s battery.
So if you’re looking to maximize the amount of power you get from the power bank, the most sensible way would be not to use your phone while it’s being charged.
Reduced battery lifespan
Another reason for avoiding to use your mobile while it’s being charged with a power bank is the fact that heat tends to also reduce battery lifespan. Thus, if you want your phone battery to last for the longest period of time possible, you’d avoid using it while it’s being charged, regardless if you charge it with a power bank or with a traditional wall adaptor.
More on ways to increase the lifespan of your battery in this article: how long do cell phone batteries last?
Longer time to reach a full charge
Yet another reason would to not use your phone while it’s being charged is that it will take longer to reach a full charge. It might even be possible that it won’t even be able to reach a full charge altogether. This depends on the amount of power that is delivered by the portable charger and the resource drain of your usage style. For example, if you’re using your phone intensively and the power bank can only supply 5V/1A, it might even be possible that the battery will continue to decrease in charge, albeit at a much slower rate. But overall, you might see the charge going down instead of up.
While the above reasons might be pretty mild and acceptable, you should know that in some rare cases there might be some more extreme consequences. These cases tend to happen if the mobile and/or the power bank are very poorly built or if they have been previously subjected to maltreatment. Here’s what might happen if you’re really unlucky:
- The phone battery might simply die and become unusable with no other sign of damage
- The battery might get bloated. This will lead to your phone getting swollen and maybe you’d start to smell or even see smoke coming out of the phone.
- The last and worst-case scenario is your phone’s battery catching fire and/or exploding. Although very rare, these accidents do happen. For example, we’ve documented some cases of power banks exploding.
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