Charge anywhere?

We have found that the standards related to 220VAC outlets has changed over the years.  There is no knowing what outlet will be available at any location.  The car can either carry several dongles, or we were pointed toward a more universal solution.

We built this solution and have had several occasions to use it.  The theory is that any house with 220V service has multiple 110V outlets on either leg of the 220V.  Therefore if you plug one 110V plug in to the wall, and then find another outlet that lights the neon light between the two blades you will have the 220V needed to charge.

In practice we have found that it is imperative to carry a circuit tester like:

Our first attempt to use the adapter box system pointed out that in one of the outlets the Hot Line was on the round ground pin, the White Neutral on the Hot blade and the bare Ground on the neutral blade.  We blew a fuse and went on to find that many sockets in the house were all wired "randomly".

The second location we attempted to charge at had reverse polarity on some outlets, and we also have come to the conclusion that this system will not work with any GFCI protected outlets.  As universal as we expected this solution to be, it has not panned out well yet.