If you do the math, at 110 volts and 20 amps, a full charge on 250KW would take 113.6364 hours or about 4.73 days.
However... That assumes 100% efficiency of the equipment used to charge the battery. I doubt the process is more than 85% efficient. It may be less. 85% efficiency would yield a charging time of 133.7 hours or 5.57 days.
I’ll check on cost per kw/hr and figure out the cost.
If you assume the national average of 23 cents per kilowatt hour and the vehicle range of about 300 miles, it works out to approximately 20 cents per mile for the electric bill.
Compared to $3 per gallon gas, the equivalent is about 15 miles per gallon. The EPA says the Hummer averages 12 mpg, so the cost gas is about 5 cents per gallon more than equivalent electricity at 85% charging efficiency.
Next question: How many miles, at 5 cents per mile savings, does one have to drive to recover the extra cost of the EV and all of the equipment needed to go with it. (Of course that doesn’t include the increased depreciation because of battery disposal and replacement costs.)
Answer: There is no chance the vehicle will last that long.
Analysis: The current crop of EVs are not a good option.
Note: The supercharging stations are rated at about 90% efficiency. Car and Driver rates home chargers at 85% during ideal conditions and less when not ideal.
Here’s another interesting math revelation.
A 250 kW battery has the energy equivalent of about 7 gallons on gas!
So, you’ve bought a massively heavy SUV with the equivalent of a 7 gallon fuel tank.
And the tank fills at the rate of .06 gal/hr. Or about 1 mile range per hour on the charger.