iPad battery test – what really matters?

There are a lot of myths about iPad battery life and how to improve it. Some of these are outright lies, but most are at least based on facts and simply stray from reality. Since battery life is an important thing for pilots, let’s separate fact from fiction so you can get the most out of your iPad next time you fly.

We’ve previously covered how to properly charge your iPad, so in this article, we’ll take a look at how your iPad battery performs after it’s charged. Are there certain settings or configurations that hurt battery endurance?

Do all those apps in the background reduce battery life?

One of the most popular theories is that running multiple apps in the background–that is, recently closed apps that show up in the multitasking view–will affect your battery life. Some pilots religiously close all open apps except for the one they’ll be flying with before taking off. The theory is that, with all those programs running simultaneously, your iPad has to work harder. Prime suspects are apps that use “location services,” meaning those apps that use GPS to determine where you are.

The other popular theory is that turning up the screen brightness will decrease battery life. This one is more obvious, but is it really as important as some people say?

There are no simple answers here, because most iPad battery tests are carried out by non-pilots sitting on the ground. So what you read on general iPad sites does not necessarily apply to pilots. We wanted to see what the results are when used for typical general aviation uses, so we set up a side-by-side test.

The test

We took two iPad Minis that were purchased on the same day (so total battery cycles are very close) and loaded them with the latest version of iOS (8.4). We then connected each to a Stratus 2 ADS-B receiver and ran ForeFlight side-by-side. The goal was to compare two iPads that are nearly identical to each other, under real world conditions.

In test #1, one iPad had only ForeFlight open, while the other had ForeFlight open and 15 other apps in the background. We ran this scenario for an extended period of time. In test #2, one iPad had screen brightness turned up to maximum and the other had screen brightness turned down to about 50%. Both iPads were running only ForeFlight.

Results

In test #1, the iPad with multiple apps in the background showed no difference in battery life versus the one with only ForeFlight. This really makes sense. Without getting into the technical details behind iOS and how it handles multi-tasking, the important thing to understand is that those apps in the background are not running. They are in a frozen state, and most use no power at all until you bring them forward as the active app. There are some apps (especially news and map apps) that do stay partially active in the background, and these can affect battery life. But this is mostly true on the ground, when connected to the internet, so it’s not a situation we encounter in flight. In the air, that newsstand app won’t be constantly updating because there’s no data connection.

Reducing the screen brightness matters – a lot.

On the screen brightness test, results were much more noticeable. Maximum screen brightness reduced battery life by about 25% compared to the iPad with screen brightness at half power. Turning the screen down even more would probably have exacerbated the effect, but those lower settings aren’t realistic for cockpit use. But the takeaway is clear: screen brightness matters, and you should set it to the lowest level you can stand if you need full iPad battery life.

What matters

In reality, there are dozens of variables that affect battery life, but here’s what matters most:

1. Using wireless connections (WiFi, Bluetooth, LTE cellular) clearly reduces battery life, in the neighborhood of 30%. Most pilots will be using one of these (to connect to an external GPS or ADS-B receiver, or just using the internal iPad GPS if it has one), so there’s not much you can do here. But you should remember that, in dire cases when you need to be able to read a chart at your destination, you can turn off all of these connections (Airplane Mode ON) to squeeze a few extra minutes out of your iPad. More realistically, if you only plan to use the WiFi connection in flight, turning off Bluetooth and LTE will improve battery life. LTE in particular takes a lot of juice to connect to cell towers, and some apps may try to update with the data connection. See our tips for pre-flight setup for complete details.
2. Screen brightness is also a significant factor. Many pilots default to max brightness for flying, and there’s nothing wrong with that if you’re trying to overcome glare or bright sun. But recognize that this setting will reduce your battery life by at least an hour compared with a mid-brightness setting, and up to 3 hours compared to the lowest setting. Simply turning off the screen (by tapping the power button on the top right corner of the iPad) can also save a lot of battery life.

Other things can make a difference too, but not nearly as much as the two above. These include keeping your iPad updated to the latest version of iOS, since Apple often improves battery life via software updates. Also, keeping your tablet as close to room temperature as you can will help. That may not always be possible in the cockpit, but at the very least, you should never leave it in the airplane overnight or in direct sun. On the ground, turning off Background App Refresh can help, but this isn’t much of an issue in flight.

In the end, you should get at least 4 hours out of your iPad battery, which is enough for most flights. With a newer battery and with smart management, that number can be extended to 6 or 8 hours. No matter what, as we always advise, carry a backup power source.