Just to give you an idea of how powerful it is, Avantek’s 20,000 mAH battery pack can charge an iPhone 5S around 11 times, an iPhone 6 Plus or Galaxy S5 around 6 times, an iPad Air almost twice and just about any other tablet more than twice. The battery pack includes two USB ports that supply a current of up to 2.4A and an additional USB port that supplies up to 2.1A. The maximum combined output is 6.3A, allowing it to charge three devices at once – all at full speed. There are four blue LED indicators on top of the external battery pack, which plays a huge role when it comes to charging the battery and charging your mobile devices. Each indicator represents how much power is remaining.

4 LEDs illuminated = 75 – 100%3 LEDs illuminated = 50 – 75%2 LEDs illuminated = 25 – 50%1 LED illuminated = 5 – 25%1 LED flashing = 0 – 5%

What’s in the Box

Charging the Battery Pack

It’s recommended that you charge the battery pack before using it. However, I noticed that it had a full charge when I first turned it on, so I didn’t charge it. It’s also recommended to use an AC adapter as opposed to a USB port on your computer since the latter will take much longer to fully charge the pack. I chose to use a USB port on my computer, and it took approximately six hours to charge (starting at two illuminated LEDs). If I needed to use it sooner, I’d definitely go with an AC adapter as recommended.

Using the Battery Pack

Avantek’s external battery pack can be used with smartphones, tablets, MP3 players and more. It features a smart circuit that automatically recognizes your devices as soon as you plug them in in order to optimize the charging current so you won’t have to worry about the battery pack harming or damaging your devices due to charging at a high power level. The battery also turns off automatically to protect the circuit if the total amperage required by your device exceeds its maximum output. I found this happened when I initially connected my husband’s Moto G to the max 2.1 A port; after around 20 minutes the battery pack turned off. After switching to a 2.4 A port, there were no issues, and it remained on until done charging. Along with my husband’s Moto G, I tested this battery pack with my Samsung Galaxy Note 10.1 2014 tablet – both in a row without recharging the battery pack. Here were my results:

Moto G – It took approximately 1 1/2 hours to go from a 20% battery level to 100%. All four LED indicators were illuminated from start to finish.Galaxy Note 10.1 2014 – It took approximately 3 1/2 hours to go from a 28% battery level to 100%. Although all four LED indicators were illuminated, it didn’t take long for it to go down to three LEDs. Once finished, two LEDs remained.

Charging cables (for your devices) are not included, so you’ll need to have your own if you plan to charge more than one at a time. It’s best to use the original cable that came with your device for the best performance. Charging your device is as easy as plugging in the charging cable and pressing the power button on the battery pack. The LED indicators then illuminate to indicate how much power is left. Although the battery pack can become warm when charging, I didn’t notice any warmth when charging just one device at a time. Personally, I found it was convenient to use the one included cable since I was charging just one device at a time. I found no issues or decrease in charging time when using it. However, this cable will not work for Apple products since it is a micro-USB to USB cable. Along with being able to charge one or more mobile devices, this battery pack also has a small built-in white LED flashlight that comes in handy in low-light areas (e.g. in a dark parking lot when looking for your keys or unlocking your car door). It can be turned on and off by quickly pressing the power button twice.

Final Thoughts

The performance of this external battery is impressive. It’s the best I’ve tried so far when it comes to charging multiple devices and providing multiple charges without having to recharge the battery. It’s not the slimmest nor the most compact, but with this much power, it doesn’t need to be. It also has some weight to it (1.2 pounds), but it’s not too heavy to carry in your laptop bag, backpack or purse. The added LED flashlight is also a nice little bonus.