Instruction: Answer the given question by extracting information from the supporting document.

Input:
Question: Can this charge it's own battery while charging other devices at the same time?
Document: I originally purchased this due to the severe battery drain on my Nexus 4 of playing Ingress for any length of time. I've found it to be an awesome product so far! Charge time is long due to the sheer size of it, but it can recharge my phone numerous times and fits comfortably in my bag or back pocket when Ingressing.Charging two devices works flawlessly as well and the flashlight works great.
I'm glad I bought this product. This is one huge external battery that keeps my devices charge for days before it needs charging. I have this for a week now and so far it performs as advertised. It definitely still needs some breaking-in time and more testing but so far it's living up to its potential. Charging this beast definitely took alot of time on a less than 1A charger. I definitely need to get a high output charger for this beast.
I take this with me on trips when I know I may not have access to conventional charging methods when needed, including using it in the cockpit with multiple iPads. I have yet to run it down to zero after recharging multiple devices at the same time. While not huge, it does have some size and weight to it which is to be expected given the capacity of this external battery. Typical of Anker, the quality is very good.
Holds charge for a long period. Great product. Can charge two devices simultaneously; although it slows down the charging time.
I like that it has two charging ports (1A and 2A) so I can charge two devices at the same time. And it's stylish and very simple to use. I was convinced to purchase the Anker Astro E4 based on the great reviews it has received. In my opinion it is a definite five star product.UPDATE: I tried the Astro E4 on the larger Kindle Fire 8.9' HD and it used about half it's capacity to charge that device.
Works just as it should. Love how I can charge multiple and different devices at the same time. Great to save space on trips. Long battery life.
Holds a lot of battery power, you can recharge your device several times with this external battery, although it make take some time for some devices to fully charge.
It charged my Galaxy Rush from 14% 5o full in under an hour, and that with it being used at the time. It charged a friend's iPhone with no issues either. And it's internal battery meter is still reading 3 bars from a full charge after both of those devices.The addition of a one-LED flashlight is another nice perk, and could be handy at times.
I got this for a week long trip where I was expecting long walks away from any power source so I would need to recharge my phone and digital camera. I can't be more satisfied, this battery charged my phone up to 90% (because after that I unplugged it) 4 times for each full charge, I did not charged 2 devices at a time so I can't tell how efficient that can be.
I purchased this in May 2013. I went with the device with the largest battery capacity hoping it would charge multiple devices, multiple times before running down. On my first try, I was able to charge a nearly dead iphone5 three times and a nearly dead ipad twice before the external battery ran out of juice. Each time the iphone and ipad were at about 10% and were charged back to 100%.
Answer: No...the external battery can not be charged as it is charging. I have tested this as well several times as I thought you would be able to.