If you own a MacBook Pro and have noticed it gets hot while charging, there could be a simple solution. Only charge it using the ports on the right-hand side of your device.
The issue seems to affect USB-C MacBook Pro models, meaning any high-end Apple laptop from 2016 onward. When charging the laptop using one of the left-hand USB-C ports, the laptop gets unusually hot and the fans start spinning to counteract the increased heat. Given that one of the selling points of Apple laptops is near-silent operation, that is less than ideal.
That’s not all. One user on the programming community Stack Exchange had struggled to work out why the kernel_task process was using so many resources on their computer — including causing their machine to wake from idle a whopping 990 times. The resource-hogging process made things so bad that their MacBook Pro became “effectively unusable” at times.
As it turns out, the root of the problem was not kernel_task itself but rather the situation that was forcing it into action. As Apple explains, the kernel_task process manages the processor temperature in MacOS, in part through controlling the device’s fans — when the operating system detects high temperatures, it prompts kernel_task to start spinning the fans. While charging the MacBook Pro and having peripherals plugged in to the left-hand ports, the device’s ports can get hot; for some reason, this can result in kernel_task going a bit haywire and using up a whole boatload of system resources.
The same is not true if you use the right-hand ports. Even though the ports get warm during use, kernel_task is seemingly ignored by MacOS in this instance, meaning no resource-hogging process slowing down your Mac.
It is not really known why this situation exists, but it is likely unintentional on Apple’s part. Until a MacOS update is rolled out, your best bet is to avoid having both your charging lead and peripheral devices plugged in to the MacBook Pro’s left-hand side.
We know Apple is working on at least one aspect of how its Macs charge up, with a new Battery Health Management system included in the latest beta for MacOS 10.15.5. We do not know whether it will fix this particular battery glitch, but we have our fingers crossed.