It's time for your smartphone battery to have a checkup

At a recent reunion, a family member was unplugging her phone from the charger and started complaining that her iPhone could not keep a charge the way it did when it was new.
She wasn't aware of Apple's new battery health options in the iOS Battery system preference.

The first step was to checked that her version of iOS was at least at 11.3 or later. It was.
Her iPhone is a 6S Plus. The Battery Health information page will only show up if you have an iPhone 6 or newer phone or an iPhone SE.
To check the health of the battery, go to Settings and then tap Battery. Touch Battery Health (beta) — the feature is still technically in a testing phase. The Battery Health information page shows two pieces of information — your phone's maximum battery capacity and its peak performance capability.
The former is the percentage of the battery's capacity compared with when it was new. So if the iPhone Plus 8 you purchased a year ago now has 93 percent capacity, it means It means the battery has lost 7 percent of its capacity. The peak performance capability indicates if your battery is causing your iPhone's performance to suffer. The battery health page will tell you if your phone has experienced a battery-related shutdown.
According to the Battery Health FAQ on Macworld.com, you'll get one of five messages: performance is normal;
performance management (throttling) applied; performance management turned off; battery health unknown, and battery health degraded
The release of the Battery Health information came about after Apple announced it had instituted performance throttling on certain phones because of diminished battery capacity.
This issue also led to Apple announcing a $29 battery replacement program for the phones that were subject to throttling. That means if you wanted Apple to replace an out-of-warranty battery, you could do that for $29 at any Apple store or through Apple's support website.
There are also things you can do to make your phone's battery last longer. The screen is the phone's biggest power user, so decreasing the maximum brightness from 75 percent to 50 percent is a huge battery life booster.
The battery setting page will also show you what apps are using the most battery power on your iPhone. The Facebook app, for example, is a giant power hog.
Android phone users can find their battery health status on a secret menu accessed by opening the phone's dialer and typing (ASTERISK)#(ASTERISK)#4636#(ASTERISK)#(ASTERISK).
Once you type that last asterisk, you'll see a few hidden menus, including one for battery status.