Electricity Cost Per Charge = 4.4 Cents

Electricity Cost Per Mile = 0.22 Cents (over 4 miles per penny)

   A common question is how much electricity does it take to charge the battery. To the right we have a charge rate graph. You can click on the graph to see a larger version. The chart shows how much power is being drawn from the 110VAC outlet during the charge cycle. Each dot represents 15 minutes of charge time. Charging occurs in two steps, these are known as bulk charge and float charge. The first step takes about 5 hours as you can see on the graph. This is where the majority of the charge occurs. At this point the charger steps down the power for the remaining 20% of the charge cycle.

   Average power utilization can be calculated by adding all of the plot points together and dividing that number by the number of plot points. In this case we take 13 and divide it by our 24 plot points for an average power draw of 0.54 amps. Watts equal voltage times amperage so we multiply 110 X .54 to get 59.4 watts. Our charge time is 6.25 hours so we multiply the average power draw of 59.4 times 6.25 to get .371 kilowatt hours.

   In California, PG&E’s baseline rate per kilowatt is $.12 (as of August 2008).  Multiply this rate (.12) times the total watt hours used (.371) to charge the battery and we find that it costs about 4.4 cents to fully charge an exhausted battery. A fully charged battery has range of 20 miles with this model so we can see that it costs just 0.22 cents per mile for electricity to operate this scooter.