Yeah, fair enough. Two car batteries in series is even better. Not easy on the batteries, but it will get the jeep out of the bush.
You can also make your own stick electrodes from coathanger wire tightly wrapped in paper.
I couldn't tell you how many pairs of sunglasses you should parallel to protect yourself...
This rig, on the other hand, is something you could pack into just about any plant and fix something with without raising any eyebrows. If you have $5,000 to spend, that is. Super handy for small jobs in hard to access places.
Hearing about it did ruin the "cordless welder" jokes my coworkers used to share.
Reminds me how the Sinclair C5 failed because the inventor couldn't source a 15 mile long power lead.
Shouldn't the sunglasses be in series?
Batteries in series, typical stick welding voltage is ~27v. You might be able to light up on one battery, but you will quickly learn why it's called "stick" welding.
I wouldn't arc weld with any number of pairs of sunglasses, that was firmly tongue-in-cheek; but yes you are right, stacked glasses would be series.
Also, if you try this, before pulling the battery from the non-broken jeep, drive it to the top of a hill so you can bump start it later when the battery is too dead to turn the engine over.