Over the last few years, we’ve been going all in on USB-C connected devices. We’re mindful of which hardware we invest in, trying to avoid micro-USB, lightning or other power plugs.
The major advantage of trying of trying consolidate your plug type was to reduce e-Waste. I’m not sure that’s actually working, as now we need new wall adapters to handle USB-C plugs, or buy USB-A to USB-C cables, but maybe short-term setbacks are long-term gains?
Post-COVID, we haven’t traveled much, but recently we took a trip and forgot that once you leave the house, so many places (Airports, Airlines, Hotels, etc.) are all invested in built-in USB-A ports in furniture. Even thought we have load of USB-C to USB-C cables, they either now need an adapter or we’re bringing a wall plug (which also needs international adapters) that take-up electrical outlets.
All this made us rethink our charging port migration plan. We’re smarter about what we take with us, what we hoard and if wireless charging is the best route?
To help us figure out all these puzzle pieces we bought two pieces of hardware. A USB-C to USB-C cable that has a small LED screen that tells you the power draw when a device is plugged-in and a USB-C to USB-C extender. This allows us to plug-in any other cable with a USB-C plug on at least one end. Using this we can profile the cables for all our devices, adapters and outlets to best optimize what we bring and use.
USB-C Wattage setup
We are mostly in the Apple eco-system with a few additional devices that we bring along. The first test was to look at the maximum power-draw from each device. We used an Apple 67W USB-C charger and a MagSafe charger capable of 15W. (They now offer a MagSafe charger capable of 25W)
| Device | Wired | Wireless |
|---|---|---|
| MacBook Air M2 | ~60W | – |
| Apple Vision Pro | ~60W | – |
| iPad M1 Pro | ~30W | – |
| iPhone 13 Pro* | 21W (30% charge) | 13W (20% charge) |
| MagSafe Battery* | 15W (15% charge) | |
| Apple Watch Series 5 | – | 1-3W |
| AirPods Pro | 1-2W | – |
| AirPods Max* | 1-2W | – |
| AppleTV Remote | 1W | – |
The 1-2W ranges are probably because the device is drawing ~1.5W and the cable’s display couldn’t do fractional values. Newer Apple Watches can also fast charge so the Wattage has probably increased, but it will only be slightly.
Apple only sells USB-C wall charges at 20W and greater. We have several old Apple 5W USB-A chargers which could easily charge the headphones and watch.
At the other end of the spectrum, the iPad and MacBook Air can be charged with the 30W charger. We have a dual 35W charger which fits perfect for charging the big devices and small devices simultaneously.
Depending on your version of iPhone, it should charge between 21-27W, so the 30W charger is plenty enough power. (And that’s to achieve fast-charging, a 20W charger is fine.)
According to the table, with the exception of the iPhone, devices that can charge wirelessly draw way less than the 15W MagSafe provides. The iPhone would charger slower via wireless than wired, unless using the newer 25W MagSafe wireless chargers.
⚠️ Beware that not all USB-C cables are equal! Apple sells 60W and 240W cables! For most devices, 60W will be fine, but if you have other no-name brand cables, your milage may vary. The cable we used in testing which had the LED screen was rated for 100W.
USB-A adapters
Now that we’ve looked at all the different devices and their power draw, what happens when you’ve only brought your USB-C cables, but the wall chargers are USB-A? Well, you use your C-to-A adapter and let’s see what happens. We are using Apple’s official USB-A to USB-C adapter. That reduces the maximum wattage flow to 5W.
It doesn’t matter what wall charger power you have, once put a USB-A to USB-C converter in the path, you won’t get more than 5W of power. This could be because the adapters are not PD (Power Delivery) so they won’t go higher than 5W to protect the hardware.
Using an adapter is fine for the headphones, watch, etc. But for the iPhone you need to either bring a second USB-A cable, or forego any built-in USB-A outlets in favor of your own wall charger.
🚨 For security reasons, you should NOT be using a random USB wall outlet. If it can deliver power it could also be reading data. To prevent this you need to put something in between, that could be a special device to block any data, or a simpler solution to charge wirelessly which doesn’t transfer!
Other chargers are available
There are lots of super interesting and powerful chargers on the market. Anker makes a bunch of small GaN charges with various ports.
We made a choice a while ago to not carry international converters, but rather the ‘duck heads’ for Apple’s chargers. For us the dual 35W charger which we can easily swap US, UK and EU heads is a winner. Your personal preferences and requirements will vary, find what works best for you.
Energy Cost
On thing to remember is the hidden costs of wireless charging. It is estimated that up to 50% of the energy is lost in heat. If it requires 1 unit of energy to charge your device’s battery 1 unit via a wired connection, then it will require 2 units of energy to do the same wirelessly: 1 unit to the battery and 1 unit lost in heat. There is a non-zero cost in your energy bill charging wirelessly.