Andrew, just gut feeling, I personally wouldn't have one. And I own about 20 Lipos of various sizes for model planes. And often need to jump start cars and tractors in cold winters. But I wouldn't want a lipo based jump starting system even if it was free. That's based on the danger factor. That thing scares me. And I know and handle lipos regularly.
For effectiveness, my guess is:
Lipos normally are classed for output by C factor.
That lipo has a C of 16.8 (16,800 mah capacity).
Max output generally ranges between 20C for cheap cells to about 50C for expensive lipos. So the usable amperage output would be in the range of 20 to 50 times 16.8 A, or 336 A to 840 A.
Above those rates and there is a real risk of overheating, fire or explosion. Lots and lots of R/C modeler's house fires have been caused by lipos a tenth of that size, just by overcharging. At the very least, an overheated (or "puffed) battery must be discarded. And that is serious business since they are hazardous -- you need to be able to discharge a damaged cell safely down to zero. And if successful, you've still lost your investment.
Okay back to usefulness. So Lipos output is very adversely affected by cold temperatures, but say you have a high quality one and it's warm -- you've got say 500 cranking amps for a total of 16.8/500 = .0336 hours or 2 minutes. That's to full allowable discharge. Actually, you won't achieve that much time, realistically at that rate. And better not over-discharge, otr you're asking for a puffed cell (ruined, and yet dangerous)
Will 500 cranking amps get your particular piece of equipment started? If so, okay, now calculate the wire size to deliver 500 amps. And compare that to the leads and clamps delivered in the kit. If the kit leads are too small, expect reduced starting power and overheated cables.
Anyway, that's a start on a realistic idea -- maybe it would all work out for your usage -- that's the only real determinant.
The other big thing I would worry about is, the charging system for a giant lipo like this is serious business. I'd expect to spend well over $100 for a reasonably safe smart charger for this size rig, and even then I wouldn't charge inside the house, and would have it in a special fireproof charging container that could handle a big lipo fire or explosion. Most lipo fires happen while charging.
Not to be discouraging, or anything........
