Hi Rick, First of all I would like to thank the gang on the Ranger EV listserve for that website, THANKS. I'll try to answer your questions. You need to measure the Killowatts going into your charger and you can divide that by the miles driven. This will give you KW per mile, there will be some loss from the charger if you could measure the KW's coming out of your charger at the same time you could calculate the loss. Your range will be effected by wieght of the vehicle, rolling and wind resistance, KW capacity of your battery pack, and also the efficiency of the motor, controler (the higher the voltage the better) and drivetrain. To measure the battery capacity, you must have a known load and discharge for a set time. There are exact details on the web I'm sure. If your going to be in the office, ha ha. There are E=meters that will measure a lot of this info why you drive and recharge, but do the research before you buy!!!