Getting Battery Health Information on iOS
<p>There are currently apps in the app-store (so it does not require jailbreak) that tell you :</p>

<ol>
<li><p>Exact percentage value of battery level you have on your iPhone. I
have tried Apple's official <a href="https://developer.apple.com/library/ios/samplecode/BatteryStatus/Introduction/Intro.html" rel="noreferrer">Code Sample</a>, although it tells you when your iPhone is charging and discharging but it gives me values in 5% steps. How do these apps get exact values of <strong>battery percentage</strong>?</p></li>
<li><p>Applications like <a href="https://itunes.apple.com/app/apple-store/id1048805552?mt=8" rel="noreferrer">Battery Health</a> show </p>

<ul>
<li><strong>Current Maximum Capacity</strong> vs <strong>Manufacturer's Capacity</strong></li>
<li><strong>Current Discharge Rate</strong></li>
<li><strong>Lifetime Battery Cycle Count</strong></li>
</ul></li>
<li><p>The same application also gives information about the <strong>Charging Rate in Watts</strong> when the phone is charging (check images) and current <strong>Charger's Power Rating</strong>. </p></li>
</ol>

<p><a href="https://i.stack.imgur.com/iHIuS.png" rel="noreferrer"><img src="https://i.stack.imgur.com/iHIuS.png" alt="Application: Battery Health screenshot 1"></a>
<a href="https://i.stack.imgur.com/68f7y.png" rel="noreferrer"><img src="https://i.stack.imgur.com/68f7y.png" alt="Application: Battery Health screenshot 2"></a></p>

<hr>

<p><em>How do these applications get so much detail about battery health when [UIDevice] provides so little information about it and almost no information on battery health and performance.</em> </p>