Got the call from Franklin Electric today, the buck transformers arrived. They will be by next week to knock my line voltage down to 240 volts from the 252 volts that PSE&G supplies. This will be the end of my cold weather charging problems.
I have heard that voltage tolerance is actually a regulatory function, meaning a political decision in the local area. A friend up in upstate NY who works for the power company says they can deliver plus or minus 10% of nominal, which surprises me. (Nominal being 120 or 240.) If I recall correctly, the good folks at quick220.com were telling me that the Arizona utility they talked to aims at plus or minus 5% for class A service, meaning not at peak load in the summer. Class B service is plus 5% minus 10% tolerance. This makes sense. I have seen minus 10% at work in the summer, which works out to 108 volts.