I bought this after see a AAA service truck using one after my regular booster pack died. I actually bought a second one for my sister who is a school teacher and she used it more than me helping her fellow teachers with a jump. Much easier to store and the lithium batteries in it discharge at a much lower rate so you don’t have to keep topping it off as much. Comes in a nice case with all leads and even charging cables for your phone or laptop( comes in handy during a power outage) You can usually get it cheaper when it’s on sale at Harbor freight.I purchased this one in Dec 2013 (according to Amazon), and it still works. My first batttery pack (Walmart brand) only survived 3-4 years. Of course you need to keep them topped off.
Q: Wouldn't those engine covers still prevent you from using one of these devices?
One day I'll pop my hood and do a look-see.

450 Peak Amp Portable Lithium Ion Jump Starter and Power Pack
Amazing deals on this 450A Jump Starter And Li-Ion Power Pack at Harbor Freight. Quality tools & low prices.