What Is Pass-Through Charging?

Need to charge your battery pack and your smartphone simultaneously? Well, you can, so long as your devices support pass-through.

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Pass-through charging technology is increasingly becoming handy in the modern world, and you'll find it in power banks and other select devices. Pass-through charging has transformed power banks that have long been regular bricks of rechargeable batteries to do more than just store power for later use.

This article explains the meaning of pass-through charging, why it matters, its advantages, and more.

What Does Pass-Through Charging Mean?

Pass-through charging is a technology that allows a device like a power bank to be charged and simultaneously charge another device by allowing electricity to "pass-through" it from the energy source. To put it into perspective, imagine connecting your phone to a power bank connected to a wall outlet.

With that in mind, you might be wondering why you should use pass-through charging in the first place? Well, it's very convenient. One of its practical applications is when you wish to charge your phone, or any other USB device, and power bank simultaneously before heading out but only have access to one outlet. Thanks to this technology, you can simultaneously charge both instead of prioritizing one over the other.

Another benefit of pass-through charging is energy stability, so you can forget about power surges potentially damaging your expensive flagship smartphone. Besides, your phone will continue to charge even when the energy source is cut off completely. Here are some tips for avoiding power surges on your USB ports.

How Pass-Through Charging Works

Under the hood, pass-through charging technology relies on a series of power regulating circuits. These circuits control the whole process by prioritizing and controlling where the power entering the battery goes.

The power bank sometimes might pass all the input power from the energy source to the output device. Other times, it will match the required power draw by the output device and then store the remaining energy for later use, hence charging both devices at once.

Is Pass-Through Charging Good? Does It Have Downsides?

Pass-through charging technology is advantageous, but it doesn't come without downsides. One of the critical limitations is not expecting your phone to charge at full speeds relative to plugging directly into a wall outlet.

In this case, you're limited by the maximum power output of your power bank, the maximum power draw under pass-through charging, and the number of connected devices. Even if you get the best power banks on the market, there's no way around this.

Secondly, pass-through charging is not as efficient as connecting your device directly to an energy source. This is also the reason why wireless charging is not attractive. The technology is also not without risks, which explains why it's unavailable on many power banks and battery packs. When charging a device, your power bank generates heat. Charging it at the same time generates more heat which results in inefficiencies.

The specific percentage of energy lost through heat will depend on the efficiency of the power regulating circuits. And as you may already know, heat is not good for your batteries, especially lithium-based batteries. As such, despite its convenience, this heat stress will shorten the lifespan of your power bank.

Pass-Through Charging Support

Commonly, pass-through charging is available on power banks. But due to safety issues, it can be hard to find. However, you'll also find it in battery packs, USB hubs, and docking stations. For the last two, you'll commonly see a dedicated USB-C Power Delivery (PD) port with which you can connect your laptop's charger to enable power transfer to your laptop via the dock.

Charge Your USB Devices With Pass-Through Charging

Pass-through charging technology allows you to kill two birds with one stone. It's commonly available on power banks, battery packs, hubs, and docking stations. However, this technology can be an issue for power banks and battery packs as it can shorten their lifespan due to the heat produced while in use.

Regardless, ensure you look for pass-through charging support when shopping for your battery pack or USB hub. For power banks, take pass-through charging as a plus but not a mandatory requirement.