You can see the problem, right? 87W charger, but only 60W coming in to the computer for charging.

Now, let’s try swapping out the Apple cable for a third party USB-C cable and watch what happens when we relaunch the System Report:

Most importantly, though, look at the “ Wattage (W)” field, which shows that the computer is getting 86W of power, a fast charge for this device. That shows it’s a proper Apple 87W USB-C Power Adapter, and even shows its serial number. Click on that, scroll down on the right side of that window and you’ll get this information: See the button labelled “ System Report…“? Click on that, then scroll down on the left side to find the “Power” entry. Key to realize: the wattage specified isn’t necessarily the wattage that the computer receives when charging. The very latest bump up slightly so my MacBook Pro with TouchBar has two official Apple options 61W and 87W. In fact, I learned some things about charging systems as I was writing this post, so I should thank you for your original question! First off, the key variable is wattage and it’s calculated easily as amperage * voltage. Apple has four different chargers depending on your notebook or computer model: 29W, 45W, 60W, and 85W varieties. Even with an Apple charger, if you have a USB-C system like I do and use a third-party cable, that cable itself might drop the wattage down and slow down the charge.

Cables, chargers, both can have a surprising effect on your power and charging experience with a Mac system in ways that are not at all obvious. Ah, you’ve opened up a Pandora’s Box of complexity when you move to third party anything in the Apple ecosystem.

Macbook 2015 charger not working