The below post mentions volts, amps and watts – to learn the basics of what they are, please see our Power Basics series of blog posts.
A phone’s battery life is no new issue – we’re using them more and more, so the batteries die quicker, you can’t get through the day, yadda yadda. The first solution is for the OEM’s (Original Equipment Manufacturer) to use a bigger battery without adding too much size to the phone. Most OEMs, like Samsung, did just that – their batteries are much larger and last through the day more easily. Others, like Apple, are annoyingly slow to the uptake; their batteries have barely evolved and are some of the smallest, most easily drained batteries a smartphone has to offer.
So, the next solution is to make the phones charge faster. If it’s going to die quickly at least it can charge quickly right? But how does that work? Can all phones charge super fast? Nope. Charge speed is contingent upon two important factors: the output of the charger and the input of your device (phone, tablet, whatever). When it comes to charge speed, you’re only as fast as your weakest link – that is to say, you can only charge as fast as your charger or phone will allow. Some chargers are built to charge at super-fast speeds, but some phones are only meant to charge at slow speeds (like the iPhone).
Chargers and devices are rated for the power they can deliver and/or receive. The output of a charger is the maximum power it’s able to deliver to a device. The input of your device is the maximum power it will receive. So, take the slowest power between the two of them and, unfortunately, that’s your maximum charge speed. For example – an iPad charger has a maximum output of 10W (5V*2A), whereas an iPhone has a maximum input of 5W (5V*1A). So when you plug the phone into the charger, the maximum charge is only….5W. You could plug the iPhone into a 100W charger, and it would still only charge at 5W. On the flip side of that, an iPhone charger has a maximum output of 5W, whereas the iPad has a maximum input of 10W. So, plug the 10W iPad into the 5W charger and it will still only charge at 5W! You could plug a 100W device into the iPhone charger and it will STILL only deliver 5W of power.
To make that charger deliver any more power you’d have to change its electrical engineering. All you nerds are welcome to do so but for the rest of us, we just have to settle for “it is what it is”. To reiterate, your charge speed is only as fast as your weakest link – so when buying a charger, make sure to match it to your phone’s input so that you’re always getting the maximum charge speed.
