I think a 120v is just fine
I think a 120v is just fine really. I drive a Volt so a bit of a different situation but just stringing a large power cable from my apartment to my space has been perfectly ok. Someone even does the same thing... just he uses it to hot box his garage so... eh, least no one complains. What is unique about where I live though is that the owner of the property is ok with occupants adding the infrastructure to the unit. I can have someone come in and install a permanent line from my apartment, to my parking space for added security beyond an extension cord. Granted this is a very unique situation but I have seen few places in Los Angeles allowing people to do this, or tap into the already existing power of the complex as a whole to just charge up over a standard plug. Finding them though has been difficult.