I keep this fully charged in the storage shelf next to my MAC-10.
http://www.amazon.com/Electronics-CPP-7500-JumPack-Portable/dp/B00IZGWL1W/ref=sr_1_sc_1?ie=UTF8&qid=1431357850&sr=8-1-spell&keywords=cobra+jjumpack
It will jump start an SUV.
I just got one of those and it's awesome! My sister gave to me for a bday gift. My lawn tractor was dead and fired it right up, so cool!