・The difference between 1A and 2A is the amount of current that can flow.
The 1A and 2A on AC adapters and mobile batteries are numbers that indicate the difference in the amount of current that can flow through the USB port. The higher the number, the more electricity can flow through it, so 2A can supply more current to a smartphone or tablet than 1A.
More current means a much higher charging speed, and 2A will charge your device faster than 1A.
In fact, using the iPhone as an example, comparing the charging speed of a 1A charger and a 2A charger, the time it takes to go from 0% to 100% using a 1A charger is about 2 hours and 20 minutes, while a 2A charger takes about 1 hour and 55 minutes. If you look at the total charging time, it’s only about 25 minutes shorter, but if you compare the percentage of the battery that can be charged after leaving it at 0% for an hour, the 1A charger takes 60% and the 2A charger takes 87%, a difference of 27%. (Both measurements were taken with an iPhone 6s)
The reason for the 25-minute difference in total time is that when the iPhone battery level exceeds 70%, a function that reduces the amount of current flowing forcibly to reduce battery pain operates, slowing down the charging speed.
Some tablets, such as the iPad, require an AC adapter that supports at least 2A output for charging, and in some cases, 1A output is fundamentally insufficient for charging.
・V represents the power to push out electricity.
Next, let’s talk about the unit V, which is always written together with A.
V” (volt) is a unit of force that pushes out electricity, like the speed of water flowing in a river.
By the way, “A” (ampere) is a unit that represents the amount of electricity flowing, and if we compare it to a river, it is like the width of the river.
For AC adapters and mobile batteries, the number 5V is most commonly used.
As mentioned earlier, this indicates that “the power to push out electricity is 5 (a river with a water flow of 5).
AC adapters, mobile batteries, and cables that use the USB-A standard are generally not allowed to use any other V than 5V, and rarely use any other V than this. However, Qualcomm Quick Charge provides a voltage of 9V or higher to the USB-A terminal for safe and fast charging, so it cannot be said that products that use voltages other than 5V are dangerous.
If it is 5V, the only factor that affects the charging speed is the number of A’s, so you don’t need to think too much about the number of V’s. However, this is only the case for USB-A.
If it’s 5V, the only factor that affects the charging speed is the number of A’s, so you don’t need to think too much about the number of V’s. However, this is only true for USB-A, and not for USB Power Delivery.