Ghetto NEMA 6-20 Charging with two 120v 20a outlets

[ATPMSD]

You cant just replace a single breaker with a tandem. They will both pull from the same leg. You need to replace two single breakers with a quad. I did this in my shop. The quad pulls from 2 legs and has a single tied 220 breaker in the #2 and 3 spot.
All the counter arguments against this assume its your house and that you can take the time to modify the breaker box and outlets. The point of a tool like this is allow tapping where proper V/A is just not available.

You misunderstood. The Tandem breaker is to make space so a dual-pole breaker can be installed.

 

[Paprika]

With the OP being of superior mind and abilities as an EE he should do what he wants. But with the obvious superior intellect of an EE, he should realize that publishing a how-to on a potentially very dangerous setup is dumb and irresponsible.

 

[Schuyler Pryne]

With the OP being of superior mind and abilities as an EE he should do what he wants. But with the obvious superior intellect of an EE, he should realize that publishing a how-to on a potentially very dangerous setup is dumb and irresponsible.

Home single phase isnt rocket science, thats why most state building codes allow homeowners to do their own electrical besides panel install. Once you understand how the 2 hots, N and G interact, you can pull all the power you want all over the house. I think its great he shared. It motivated me to build my SOL back up charger. Lots of guys like me out there, tho most are blue collar and would refuse to drive tesla. Hell, car 12v wiring can be dangerous, butt load of current plus polarity to damage parts and you.
OP just letting you know I appreciate the sharing and discussion. Ppl can do their own digging and take their own risks. I think skydiving is stupid, but I wouldnt rain on someone sharing their enthusiasm. You were up front about risks. Thats all you can do.

 

[FireFighterHil]

Can get a refurbished one for 90 bucks on ebay. Refurbished DIY220 Quick Connect 220V Power Supply, Power 208-240 Volts 841915004208 | eBay