If you’re using the iPad as your EFB paper chart replacement then you definitely don’t want the battery dying on you before touchdown. An external battery pack can be a lifesaver in today’s modern cockpit. Let’s dig into the details of the devices you carry and these backup batteries to expose what you need to look for and what to avoid.

First-off you have to know the needs of your devices. iPad require more power than a tiny Dual GPS. iPhones need less input to charge than your ADS-B receiver in most cases. The guide below is your quick reference guide to the real specs of your batteries. 





iPad Mini 1-4


4,500- 6,400 mAh

iPad mini




Original iPad 1-4  




6,600- 11,500 mAh




iPad Air 1-2



7,300- 8,800 mah

iPad Air



iPad Pro 9.7”



7,300 mAh

iPad Pro



iPad Pro 12.9”



10,300 mAh

iPad Pro

As a general rule of thumb, mobile phones only require 1 amp to charge. Larger phones called phablets may need 2 amps or more but that varies by device. Your Stratus 2S should be charged with a 2 amp charger for the best rate of charge, however, in a pinch if you needed to you can charge the Stratus 2S with a 1 amp charger. The charge rate with be slower than normal and that’s due to the number of amps it’s receiving. Let’s take a look at why that is different.



When charging your iPad, no matter which model you have, make sure you have a minimum 2 amp output USB port. Less than 2 amp is insufficient for fast charging and depending on the device may not charge at all. USB hubs for charging are typically 1 amp to 2.4 amps. It’s simple, the higher the amp output of the hub the faster the device plugged into that hub will charge.


When you’re buying a backup battery for the plane consider two things- how many mAh the battery is and the amps output the USB ports charge at. Based on the numbers above you can get an idea of the capacity your iPad has and verify that the battery you buy is larger than that.  



The Professional Power iPad/iPhone Battery has 20,800 mAh of battery and offers 4 USB ports as seen here. Two output at 2.4 amps and two at 1 amp for mobile phones. This battery is a big one - 20,800 mAh is enough juice to recharge your iPads, Stratus, and cell phones multiple times.


rugged battery

The Rugged Portable Battery Pack has two 2.4 amp USB ports and 12,000 mAh of battery. Quick charge features are built into the battery. As an added bonus the battery is waterproof when stored with the hatch door closed.

panel charger

The Dual 2.4 USB Cigarette Lighter Charger is exactly how it sounds. Two 2.4 amp USB charging ports and plugs into a cigarette lighter on the panel of your aircraft. The charger is compatible with 12V and 28V systems.


Charging your device when it’s inside certain styles of cases may generate excess heat, which can affect battery capacity. If you notice that your device gets hot when you charge it, take it out of its case first. Your device is designed to perform well in a wide range of ambient temperatures, with 62° to 72° F (16° to 22° C) as the ideal comfort zone. It’s especially important to avoid exposing your device to ambient temperatures higher than 95° F (35° C), which can permanently damage battery capacity. That is, your battery won’t power your device as long on a given charge. This means that leaving your iPad in a hot plane while you’re eating lunch is a bad idea. Storing a battery in a hot environment for an extended period of time can damage it irreversibly.

When using your device in a very cold environment, you may notice a decrease in battery life, but this condition is temporary. Once the battery’s temperature returns to its normal operating range, its performance will return to normal as well.


Dim the Screen to save battery

There are two simple ways you can preserve battery life — no matter how you use your device: adjust your screen brightness and use Wi-Fi. Cellular service requires more juice from the battery than Wi-Fi alone.

-Dim the screen or turn on Auto-Brightness to extend battery life.

  • To dim, swipe up from the bottom of any screen to open Control Center and drag the Brightness slider to the left.
  • Auto-Brightness adjusts your screen to lighting conditions automatically. To activate it, go to Settings > Display & Brightness and set Auto-Brightness to On.