I found this one in Sams Club Wednesday morning, and bought it for my home..
. Not many people were aware of this. http://www.samsclub.com/sams/stanley-300amp-jump-300amp-jumper/
The jumper battery had a 12 volt output just as your car. With a car charger
, it can charge cell phones and most i-device. It was a big difference
without worrying my cell phone to run out of power (with 4G network). The
battery was half-full when I bought it.