macOS Catalina 10.15.5 has a great battery-saving feature for MacBooks - but there's a catch
macOS Catalina 10.15.5 is now out, and the update comes with a new feature to help ensure that your MacBook's battery remains in good health, and offers better longevity as it gets older.
The idea is that the new battery health management feature reduces the rate that the battery chemically ages, and as Apple explains: "The feature does this by monitoring your battery's temperature history and its charging patterns. Based on the measurements that it collects, battery health management may reduce your battery's maximum charge when in this mode.”
It's a mode you can turn off if you wish, so it's not compulsory, but it can help to reduce the wear on your battery, depending on your exact usage pattern. If you keep your MacBook plugged into the mains most of the time - and don't use it out and about much - the overall capacity that the battery is charged to is artificially cut back, to prevent this kind of use case from negatively affecting the battery in the long-term (because you don't want it constantly being kept at 100% capacity; this is bad news for the battery).
Given that MacBook batteries aren't user-replaceable, it's obviously pretty handy to have this feature, as battery performance degrading over time can become something of a thorn in the side of MacBook owners.
The catch here is that this feature is only provided to newer MacBooks that support Thunderbolt 3, although we've seen some anecdotal reports that some older Apple laptops which do have Thunderbolt 3 haven't received the feature. At any rate, you should get it in these cases, but the only way to find out for sure is to upgrade to version 10.15.5.
As well as the battery health addition, macOS Catalina 10.15.5 applies a bunch of fixes, including the solution for a bug causing system crashes when large amounts of data are transferred over to RAID volumes.
Via The Verge