Well, it’s been a while since this BS surfaced here but like a plate of bad food from a greasy spoon restaurant it has returned. 
Assuming you’re not spamming this bogus device, save your money. It’s a scam all the way. If something like that even provided a 5% increase in fuel economy every vehicle made would roll off of the assembly line with a factory unit on it already.
And a stock alternator produces 140 amps at idle, huh?