Smartphones don't seem to shy away from labeling features as “smart” or “AI.” The last few years have seen an incredible push to put AI/smart features in every nook and cranny of the phone OS. My Samsung Galaxy S21 FE is a slightly old smartphone by today's standards, but it has most of the “smart” features that claim to extend its battery life or improve performance. These settings and features are scattered throughout the phone, and they do their best to give it a few more hours on each charge.

While it sounds promising, not every smart feature included in One UI actually helps the battery last longer. I've tried nearly everything the phone has to offer, and most of them provide only a minuscule increase in battery life. There are also massive trade-offs if you use some of these features, which forced me to rethink their usefulness in my phone routine.

Adaptive power saving doesn't fit my usage scope Unpredictable behavior

Adaptive power saving is a feature buried inside the Battery section. It's an advanced mode of the basic power-saving plan that clearly tells you which settings it will disable and offers some control. You can turn off settings that you think will impact your daily phone usage, which mostly limit CPU performance, or turn off features like Edge Panels and more.

The Adaptive power-saving plan doesn't offer the same level of transparency and only displays a toggle to activate or deactivate it. There's a small label mentioning a dynamically functional power-saving plan that will adjust everything based on my usage patterns. I've given the feature not one but multiple chances to impress me, and it failed to do so. My battery life didn't magically improve compared to the standard power-saving plan, and it was nothing more than another pesky background process competing for system resources.

In fact, if I ever use a power-saving plan, which only happens if I'm traveling, I stick to the standard one. The adaptive power-saving plan offers no real benefits for the apps I use, and the fact that I cannot see which settings or UI features it disables is even more infuriating. The standard power-saving plan works better because I can choose to reduce performance, brightness, or refresh rate. Doing so prevents me from being abruptly surprised by a lower screen brightness or refresh rate.

Background usage limits are finicky Putting unused apps to sleep

This is also a machine learning feature that tries to understand your app usage patterns and then puts rarely used apps to sleep. But the problem is, again, a lack of transparency about which apps it picks and the nature of the sleep mode it applies to each. Fortunately, Samsung offers two manual sleep modes: normal and deep. If I don't want the app to run its services or processes in the background at all, I'll prefer deep sleep to regular sleep.

In fact, I've been using deep sleep mode for a lot of preinstalled, non-removable bloatware on my Samsung phone from the first day. The list includes apps like Samsung Bixby, Avatar stickers, Samsung News, and more. Meta apps are also notorious for battery drain, but I only use WhatsApp and cannot compromise with it. So, it's not a part of either the normal or the deep sleep list.

The level of control I have with the Sleep and Deep sleep modes helps me decide which bucket the app should fall into. For example, I can put something like my investments app into regular sleep mode and receive slightly delayed market recommendations. On the other hand, a game with repeated notifications about new contests, price crashes, and other background activity can remain in deep sleep until I manually start it.

Adaptive battery needs refinement No noticeable difference

The difference between Adaptive battery and Adaptive power saving is the scope of their impact. The latter affects your phone's performance, visual effects, and UI features, while Adaptive battery is only concerned with apps. It's also an AI feature that analyzes your app usage patterns, assigns them a category, and then limits background activity based on that classification.

However, there's a big dilemma here: the feature runs in the background and might classify important apps I seldom use as “low priority.” A good example of this is an e-commerce delivery app that might receive no more than 10 minutes of daily screen time. But I rely on the app notifications to tell me the allotted delivery time, delays, and when the driver is nearby. Such apps are better off without adaptive battery optimization.

Since it's an app prioritization system that can only control resource allocation and background activity, it is even less helpful than the app sleep modes. When I keep an app in the normal sleep mode, its background activity is restricted in a way that's broadly similar to Adaptive Battery’s approach. However, it's not as strict as Deep sleep mode, and if I have to choose between Android’s Adaptive Battery and Samsung's Background usage limits, I'll use the manual mode of the latter. It can actually force-stop apps and keep them in that state unless I open them ever again.

Little battery life improvements

The aforementioned smart features didn’t yield any significant improvement in battery life on my phone. My screen-on-time metrics never spiked to a noteworthy level, even after enabling the smart battery features. I found the manual modes much better than the “AI” ones, as they offered granular controls and let me tweak the plan or settings to suit my requirements. I love the app's sleep feature, as it helps me turn off bloatware, its related background activity, and notifications without ever opening the app info settings. It’s one of the best features of One UI, saving battery better than the automatic option. I also use battery charge protection to limit its charge to 85% and prevent unnecessary degradation.