portable charger/dead battery jumper

I want to get one. Any suggestions?
I've seen some small ones, iPad sized. They any good when this small?

    I don't know about the very small units, tho I have my doubts they would work very well, and even more about jumping a car from a lighter socket, as I've seen advertised. 
    I have had back up batteries/jumpers  for 20-30 years.  They used to be about the size and weight of a bowling ball, and only lasted a few years each, but the one I have now is pretty compact - the actual lithium battery is about 1 1/2" x 8" x 3-4", but the pouch is about twice as large to hold the clamps and charger cord, about the size of a tablet case.  It holds a charge much longer when not in use than the old style, and would probably have enough juice to start a couple of cars without recharging, though I've never tried. It has a readout of how charged it is, a flashlight, and a USB port (which could come in handy in an earthquake, etc.).   It's a Die-hard, I'll bet I've had it at least 5 years.
     It gives me peace of mind, especially with my new car that has way too many electronic bells and whistles - the battery has actually gone dead during the time it took me to unload my fishing stuff, I guess because I had all the doors and trunk open and the blinkers on, started the car with the unit and had the battery tested and it was good.  Batteries also have a way of going dead at ski resorts, I suppose the cold temps, and it's a long wait for a tow truck if you can't find someone with cables even if you have cell coverage to call one.  I think I've jumped other peoples' cars 4 times as often as my own with my units.
 

I bought a beat-it jump starter a few years ago it’ll charge of 110v or 12v.  It paid for itself first time I needed it. Really good to have on the trail. Only like 50 bucks. Plenty of power to turn over the 5.4

It’s pretty damn small. Size queens wouldn’t love it

And you can charge shit off the USB’s.

Good Luck brother.

Miss you 

I've got a Gooloo unit about the size of a thick paperback.
It works great with the caveat that it needs to be charged about every two months.

The only caution I remember is. when boosting a car engine, not to crank up the engine more than X number of seconds. The time may vary according to specific brands/models.

Also, when electrical outlets are not available, I can plug in a USB hub to  charge multiple devices.

I got two from Costco

One is the giant yellow one, the other a little one in a nice little zip up case

The little one we have used more than once and will get its twin soon so we can have it in both cars

The big one works but doesn’t seem to hold a charge any longer than the little one

I bought one at a NAPA parts store a little while ago. Works just fine so far, and it has been used on several vehicles. The unit I got was the NOCO boost plus. And I just looked it up - a SCREAMING deal for it right now on Amazon.

https://www.amazon.com/NOCO-GB40-UltraSafe-Lithium-Starter/dp/B015TKUPIC/ref=sr_1_3?dchild=1&keywords=noco+boost+plus&qid=1596914457&sr=8-3

Previously I used one of the lead acid types and it too worked well enough for years, but eventually the battery gives out, and it costs more to replace the battery than to buy an new charger.

I too was leery of the lithium based models until talking to a tow driver. He used his multiple times a day on a single charge, then would plug it in at night. There are units for different sized engines - don't get one rated for a four banger if you need to start your 6.7l diesel. Size appropriately.

Good luck.