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16.4 mile commute requires ~7 kWh of charging

16.4 mile commute requires ~7 kWh of charging

Hi,
I have long range Model 3.
My commute is 16.4 miles (8.2 miles/one-way).
I charge it at night, and looking at energy history from PG&E, it looks like I'm using a little over 7 kWh to charge the car.
That seems like a lot. I thought it takes 7.7 kWh to charge 30 miles (https://www.tesla.com/support/home-charging-installation#on-board-charger).

Any idea why? I have it set so it uses only fans to keep the car cool while I'm parked during the day. Thanks!

majassow | August 10, 2018

It takes 7.7 kWh to *travel* 30 miles (about... that's 256wh/m or pretty average). It takes more energy than that to charge the battery because charging is not 100% efficient. Also, you will loose miles each day due to battery thermal management and cabin temperature control (but you use fan only). Typically about 1% for battery management (or about 3 miles -- although this varies also depending on firmware version etc.). Power for cabin temp control depends on the outside temperature and if you are parking in full sun. It can be up to 10-20 miles worth of power to keep the cabin from "overheating" with AC, I expect that with fan only, you'd use just a little more then the typical 1% you see for over night.

ron369 | August 10, 2018

Unless you think you really need it, you might consider turning cabin overheat protection off. I was losing about 20 miles a day with it on while my car was out of the sun in my garage (which was hot, but never got above about 90º). I was pulling my hair trying to figure out what might have been causing the drain, until someone told me to turn off the overheat protection. My drain went from 20 miles down to 1-2 per day.