Ryobi 18v jumper box theories?

[Ricko1966]

Fast forward to 10:30

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This thing is 200.00 not worth it in my opinion. My theory is it is a Ryobi battery with a buck converter to drop voltage to 12v. You connect the 18v battery dropped to 12v wait a minute for voltages to equalize,then start the car. I know people have gone just straight 18v to the car battery,there has to be a reason Ryobi isn't doing it that way. I do understand ohms law by reducing voltage I am increasing amperage. I am thinking of making something like this,using a $20 buck converter and junk I have laying around. Looking for input from electrical geniuses. Fwiw I know I can just buy a jumper box,I've bought many of them,thrown away many of them when the batteries wear out,I like the option of just swapping batteries,that I have multiples of.

 

[Grit dog]

Idk, I don’t think just a step down converter would do it.
Haven’t given it much thought, but don’t those little Lithium jump boxes start out at a much higher voltage? IE that’s how you get enough current to spin a big engine out of something the size of a cell phone?
I know it was impressive. Bought a cheap Amazon one for my snowbike since it doesn’t have a kick start as a backup. And was really impressed that it also fired the 454 in the K20. (Engine warm, battery totally disconnected)
Just spitballing

 

[Ricko1966]

Well for the people that didn't watch the video,and I don't blame you. This thing doesn't work like a normal jumper box. You hook it up push a button wait 60 seconds then try to start your car,if it doesn't work you push the button again,wait 60 seconds again. My theory is they are using a step down converter and giving the dead battery 60 seconds of charge. I'm thinking I could do the same thing with a buck converter and a momentary contact switch.

 

[Tonimus]

A 4s lipo has a "nominal" charge of 14.8V. Full whack is 16.8v. A dead battery will rapidly bring that voltage down. You can get a halfway decent 4s lipo, charger, and battery clamps for about $100. Full disclosure, I have jumped my 2016 buick with a Ryboi 18v battery directly. Jumped my 2010 GMC with a 3s lipo. YMMV.