Originally Posted by milkytron
I wouldn't buy it. If you need more battery, check out Anker portable chargers. I haven't had a problem with mine after a year.
Sent from my Nexus 5 using XDA Free mobile app
is very slim you can have it plugged in pocket with the phone.
Note that when using a battery to charge a battery you get two lots of 20% loss from the electronics in the external and internal so 5000mah becomes in reality about 3000mah, so you're going to get max time if you connect the external battery during times of peak power use of the phone, such as when sat using the phone so you get only one lot of 20% loss so 5000mah becomes more like 4000mah not 3000mah so if you plugged it when using your phone at times of when plugging a battery is not an issue then you're nearly tripling your overall times.
Also note that not external batteries are the same, a key one is if they are 1A or 1.5A or 2A input, the 1A input take a long time, usually overnight, to charge. The above one is 2A.
If I'm travelling I pair with a dual socket 2x2A brick like this one
. So from any time I'm sat next to a power socket I'm making best use of the time charging 2A to the slim battery and 2A to the phone. That means you are not increasing your charging time at same time as tripling your battery time.