Tec-lation : The Translation of Technology
USB C Power Delivery (PD)
How Long Does It Take To Recharge A Powerbank?
Jay Terry / Published: Apr-05-2018
You may have found this article because you want to know, “How long will it take to recharge my powerbank?”.
My answer: Well, it depends. Here’s why:
Without knowing which power adapter model, charging cable and powerbank model you own, I would have an equal chance of guessing how long it would take you to walk to the store without knowing anything about where you live.
My goal in this article is to give you a better understanding of how it all works, along with some tools to estimate the time needed to recharge your powerbank based upon using YOUR equipment.
There are 3 primary pieces of equipment used when recharging a powerbank. I think it’s important to have a basic understanding of them, so let’s take a deeper dive into them.
The Power Adapter
Customers are typically recharging powerbanks by connecting the device to an AC power adapter (sometimes referred to as a “wall charger” or “power brick”). However, not all power adapters are created equally. The type of output ports available on the unit and the power profile (Voltage/Amperage or Wattage) are very important factors.
For example, the charger that came with your Bluetooth headset or iPhone will typically output much less power than power adapters designed for larger devices.
The 3 most common types of power adapters have a
1. USB-A port (sometimes called “Standard USB”)
2. USB-C PD port (sometimes called “USB Type-C” or “USB PD”) or
3. a combination of both.
USB-C PD ports will typically charge devices much faster than a standard USB-A port because it has the ability to output larger amounts of power.
In general, the maximum output of a USB-A port typically ranges between 2.5W and 12W, while the maximum output of a USB-C PD port typically ranges between 18W and 30W. While there are some USB-A ports that can support up to 18W and USB-C PD ports that can support up to 100W, these are not very common and it’s unlikely that an average customer has one without knowing it. As you can see, the difference can be substantial.
Helpful Hint: Be sure to check the output power of your power source and the port you are using. This can typically be found on your power adapter or in the owner’s manual.
To learn more about output power and how you can easily figure it out, be sure to check out our article on this.
Note: Your power adapter may have one, two or more ports.
There are 2 primary types of cables that you can use to recharge your powerbank.
- The most common will be a standard cable with a USB-A connector on one end and a Micro-USB connector on the opposite end. With one of these cables, you’ll simply plug the USB-A connector into the USB-A port on your power adapter and plug the Micro-USB connector into the Micro-USB port on your powerbank.
- A less common type is a USB-C to USB-C cable, which has a USB-C connector on both ends. These cables are reversible, so you can plug either end into the USB-C PD port on your power adapter. If your powerbank has a USB-C input port that accepts USB-C Power Delivery (PD), using this instead of a Micro-USB port can drastically reduce the recharging time.
Once again, not all cables are created equally. If you are using a USB-C PD port to recharge a powerbank that accepts more than 60W input, check out our recent article that explains more about the cable requirements.
The Power Bank
When recharging a large powerbank (over 20,000mAh), you must keep in mind that its battery is significantly larger than your phone battery.
Due to this, you’ll want to charge it with as much power as it can accept if you want to charge it quickly.
Each powerbank model will recharge differently, as the input ports and the amount of power it can accept will vary greatly. In general, most powerbanks can be recharged by using its Micro-USB port or USB-C port. If you don’t see a port labeled as “In” or “Input” on your powerbank, you can typically find this by looking at the fine print on the unit or in your owner’s manual.
Once again, not all input ports are created equally. The maximum power input that your powerbank will accept is typically listed in the fine print on the unit or in the owner’s manual.
In general, Micro-USB input ports on powerbanks will accept between 5W and 12W of power, while USB-C input ports can accept between 5W and 45W of power (some will accept up to 100W). To ensure that you’re charging your powerbank at the fastest rate possible, you’ll need to ensure that the power profiles match. To learn more about this, check out our article on the importance of voltage and compatibility.
Why It Takes So Long To Charge A Power Bank
With all this being said, you may be thinking to yourself “Ok, I still don’t know why my powerbank takes so long to recharge…”
To make things easier to understand, I like to find similarities between technology and everyday items. I usually compare the battery in your powerbank to a bucket of water, while I compare the battery in your phone to a bottle of water. For the power adapters, I compare a USB-A port to a water fountain and a USB-C PD port to a garden hose. Here’s why:
Your phone battery holds less power than a powerbank battery, just as a cup holds less water than a bucket, and a water fountain doesn’t allow as much water to flow as a garden hose, just as a USB-A port doesn’t allow as much power to flow as a USB-C PD port. Even though the opening on a water bottle is much smaller than a bucket, you can still refill it rather quickly from a water fountain. While you could absolutely use the water fountain to refill the bucket, it would require much more time to refill it compared to using a water hose.
Estimating Recharging Time
So, exactly how long is my power bank supposed to take to recharge?
I’ll start off by saying that this is not an exact science. There is a reason why manufacturers do not say things like, “It will take 3hrs, 5min and 1.3secs to recharge this powerbank.” There are many factors that will cause the time to fluctuate, but I will spare you with the technical details. Here’s what you should know:
In your owner’s manual, you may find information like, “Recharges in as little as 3 hours” and “Maximum Input: 5V/3A”.
Based upon this example, this tells me that by providing a 5V/3A current (15W) to the powerbank, I can expect to recharge the unit in as little as 3 hours.
If my power adapter only provides a 5V/1A current (5W), then I could anticipate that it may take me up to 9 hours to recharge the powerbank.
How did I estimate this? Well, the powerbank’s maximum power input is 15W (5V/3A), so I would assume that the recharging time is based upon this. Since my power adapter can only provide 5W (5V/1A), which is only 1/3 of the power it can accept, I should expect it to take 3x longer to recharge.
If you are wondering how I determined the wattage, check out our recent article on this subject.
Please keep in mind that this can change over time as the battery ages and this is not an exact science, but this should give you a good estimate.
The next time you recharge your powerbank or if you’re currently shopping for your next one, I hope this gives you a basic understanding of the subject and gives you the knowledge to make an informed decision. If you plan to use your powerbank often, you may want to make the investment in a power adapter that will allow you to recharge the powerbank as quickly as possible.
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