Pocket Sized Automotive Jump Starter

(Yeah, I have a thing for batteries.  And a flashlight thing.  And a few more odd little fetishes.  What's it to ya?) :D

A few weeks ago, the lovely and has-as-bad-a-flashlight-and-battery-thing-as-I-do Mrs. Graybeard got an email ad for a remarkable thing: a packaged battery appliance that will not only charge your iPhone/iPad/Android/probably anything that uses a USB charger, it will also jump start your car.  It's an 11 Amp Hour battery in a package that will fit in my cargo pants pocket and maybe the jumper cable, too, which is short but has large clips.  It's 155x76x29 mm (LxWxH) or just about 6 1/8" x 3" x 1 1/8".   It comes in a zippered cloth case with elastic straps for the battery and some accessories.  It charges with an AC adapter, or a lighter plug in your car.  There are two USB ports on it to charge two devices at once.  One is marked 5V/1A while the other is marked 5V/2.1A. 

NewEgg sold out of these almost immediately, but I see the same thing on Amazon for a few bucks more.  A little looking around, and I find there are many similar things on the market (including a video demo) and I feel embarrassed to have not been on top of the tech.  But they're cool.  One reviewer we read somewhere said he jump started cars 11 times on one charge; others say they've jump started V8s and other big engines.  These batteries are rated to deliver a 400A peak in a jump start; if I read this right, it's a short peak of 400A and then a sustained 200A.  A little mind boggling. 

I find this a bit amazing, but I've had the little jump starters that include an air compressor, lights, and all stuff quite some time.  When you open one of those up, you'll find a sealed lead acid gel cell battery that's about 4x the size of these.  The reduced size is probably from the better battery chemistry.