kernal task is out of control

Is this why kernal task is out of control?

Probably, but whether it is or not, you need to do something about the battery. A failed battery is a safety hazard.

I think it's about $150 in the US, but that's just a guess. It depends on the model.

hensonj wrote:

... I've read that this can happen with a faulty battery. Is this true?

Yes. Don't postpone its replacement.

https://www.apple.com/batteries/service-and-recycling/

The bottom line on not having a battery or a battery that holds no charge is that you laptop will not run at full power. It will cut the CPU in half. You could remove the battery or not. Will not make a difference. Replacing it will.

As the link indicates, non-removable batteries are not designed to be replaced by the user. The harm in doing so yourself is that you may damage your MacBook Pro. This site contains many reports from people who did that describing sparks and smoke followed by an inoperable Mac. It's easy to assume the reason for that was user ineptitude, but it might not be, since it is not possible to determine just what happened in those cases.

What's worse is that Apple may refuse to repair that Mac, in or out of warranty, at any price. Having Apple diagnose and replace it — if it is in fact the direct cause of the problem you describe — does not cost much more than an aftermarket battery of dubious origin. That price includes diagnosis, parts, labor, a one year warranty, and all the risk associated with potential damage.

I'm having a similar problem on my iMac, which is constantly freezing up/beachballing at random times (often when I'm only running Safari and browsing Facebook). When I check the activity monitor, the main user is some kernal task. I can't figure out what that is! I did an EtreCheck scan and it has found some "failures" mainly involving Adobe. But I can't tell what is causing these kernal task uses as well as the constant (daily) crashes. I have a brand-new computer (less than 6 months old) and a very new (one month) 4T hybrid hard drive. I do have three external drives connected via a USB hub (backup discs), so I'm not sure if these could be causing the issue. It isn't hardware, as I've had the computer in to Apple three separate times and gotten the new hard drive. And of course, the problem cannot be replicated by the techs. Any ideas? My repair guy says the last thing he can think of doing is wiping my hard drive completely and then manually putting only the files back that I use. But this doesn't sound like a great fix to me, especially if one of the files I use is the one causing the problems. Help! Thanks.

If you are using a hub to hook up your peripherals, you might get a problem due to power leakage. Is the hub self powered? Kernel task is made up of everything that shows in the activity monitor under root. Could you post that etrecheck report?