Can You Charge a Power Bank While Using It?

Can a power bank charge and discharge at the same time? Yes, it can but you shouldn't do it very often as it can overheat the battery.

If you have just one power outlet and you need to charge both the power bank and your phone, what should you do? Can you charge a power bank while using it to charge a phone?

Yes, power banks can charge and discharge at the same time. But, the power bank needs to have the passthrough feature to do that. 

Only specific power banks come with this feature. While some top brands support passthrough, there are some top brands that don’t. Down below we will explain how this feature works and if you should use it.

Is It Safe To Charge a Power Bank While Using it?

Using the power bank passthrough feature is safe. But, you should only use it for a small period of time, and only if there’s no other option because it may overheat the power bank. 

This feature will charge both devices at the same time, but the charging process will take longer. The longer the power bank takes to charge, the more heat it will produce. The more heat the power bank produces, the higher chances of the battery getting damaged are.

The power bank getting a little warm isn’t a problem, but if the device gets too hot to touch then you could be dealing with overheating. While the battery isn’t producing the heat itself, it still may affect it. The heat is produced by other power bank electronics but it will spread to the battery by thermal conduction.

It’s not a good idea to overheat lithium batteries as that can cause different problems, including permanent damage to the battery. So you should avoid using this feature for too long or too often.

You will also waste some power due to power bank electronics compared to charging the phone directly. That’s a small amount of power that can cause some heat, but if you have a high-quality power bank then it won’t be a problem.

So, as long as the power bank isn’t overheating and you don’t care about the wasted power, then it’s totally safe to use the passthrough feature.

Things To Keep in Mind

The output of the wall charger should be higher than the output of the power bank. If your power bank has a 1V output, then the wall charger output should be higher, preferably 2V. If the charging voltage is the same, you won’t archive anything. That’s why connecting a power bank to a power bank won’t do anything (except waste power).

However, if the device (phone) is excepting a higher charger input than the power bank is offering, then the power bank will use its already storage charge to charge the device. That’s why sometimes the power bank ends up with less charge than before charging it.

If that’s the case, then it’s best to charge the phone directly. Some power banks come with LED lights that indicate when the power bank is using the storage charge.

The input current (I) should also be higher than the output current (I). The power bank capacity should be higher than the device (phone) capacity.

When using the passthrough feature, make sure to leave the power bank in a well-ventilated area. So, don’t put the power bank in a bag as it will overheat. Lay the power bank in a flat position and leave space around it.

How Does The PassThrough Feature Work?

The passthrough feature is the ability of the power bank to get the power from the wall outlet and send it to the device (phone) while also storing power. But, contrary to people’s beliefs the power bank battery cannot charge and discharge at the same time, the current (I) can only move in one direction at a time.

So, the power coming from the wall outlet splits, some of the power goes directly to the battery of the power bank where it is stored, while some of the other power goes directly to the charging device.

Why Some Power Banks Don’t Have the Passthrough Feature?

The power banks first came into the tech world in 2001. At that time, these power banks were only used to charge small devices. Those power banks didn’t have many features. But, after a while new companies produced new power banks with different features. And that’s when the passthrough feature came.

If your power bank doesn’t have the passthrough feature then it could be for two reasons: the power bank is old or the manufacturer doesn’t support it. 

Some brands such as Anker don’t support the passthrough feature because of the battery degradation.

Can a Power Bank Be Safely Charged Using Another Power Bank?

A power bank can safely charge another power bank. The purpose of a power bank is to charge a device through USB, it doesn’t matter if the device is a phone or a power bank, the power bank will charge it.

But, it’s a false economy. As you know, while charging some current (I) will be wasted. So, if you charge an empty 4000mAh power bank with a full 4000mAh power bank, the empty power bank won’t be able to fully charge, while the charged one will be empty. In other words, you will be wasting power.

Final Words

Power banks don’t come with their own adapters, so the passthrough feature is very necessary. As long as the power bank isn’t overheating then you can use it.

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