[Ron Rattie]

For a portable backup L2 EVSE I have a 120v/240v EVSE with a normal 3 prong plug and a NEMA 14-50 adapter. Means I can plug at any normal outlet up to 16A and 14-50 outlets up to 32A, plus I carry a Tesla to J1772 adapter. Those destination chargers are normally free and deliver good power.

 

[Ron Rattie]

I would get one with an NEMA 14-50 plug because I think there are more of those around, such as a dryer outlet, which often is in a garage and easy to access.

Dryers in the garage are a regional thing. In places with freezing winter temps you won't find them in the garage because of the freezing pipes. But a 14-50 comes in handy for RV parks and campgrounds and some people like my father have one in their garage to power their RV when they are home.