Tuesday, January 31, 2012

Changes for a Better EV Life: Charging at work costs less than a Mini Fridge!

Having driven CO2 Fre for over a month now, I feel I can now safely make some recommendations for change that would make my life infinitely easier.  Some of these things I've been writing about long before I purchased my Nissan LEAF; I knew going in some sacrifice would be required for the greater good.  That's not to say there aren't great things like the burgeoning Charging Infrastructure and wonderful LEAF features to help get me through the day!  But there's always room for improvement and if you don't speak up, nothing will get done.

Power Consumption

During business hours a typical mini fridge is drawing about 320 Watts (W) of electrical power.  A car plugged in to trickle charge on the other hand is using about 120 Volts of Alternating Current (VAC) × 12 Amperes (A), and thus an average of 1,440 W peak.  Note, since A/C is a sine wave, the maximum power used at the peak ends of each cycle is 2,036 W (The maximum for a sine wave with a given Root Mean Square — multiply by √2) but 0 W is used at the middle of the cycle so overall the 120 VAC average is produced.  This is therefore about the equivalent of the power used by just 4 typical mini fridges.

Daily Electrical Consumption

The mini fridge runs 24 hours a day, continuously, and thus uses about 7.68 Kilowatt⋅Hours (kWh). The EV on the other hand is only drawing power for 8 hours a day and thus uses about 11.52 kWh, and thus is about equivalent to that of the 1½ mini fridge.

Annual Electrical Consumption

In a typical year, running 365.2425 days that same mini fridge is using 2,805 kWh of electricity.  But the employee who works 40 hours a week, 46 weeks a year (including 2 weeks fixed vacation and 4 weeks flexible vacation) uses only 2,764 kWh of electricity, and that's less than what a single mini fridge uses!

Conculsion

So, wouldn't it be cheaper to ban mini fridges and allow electric vehicle charging at work?