Constantly plugged in accessories

[BuffaloTony]

Hi all,

 

I've had my C-Max for about a month now and was loving the MPG - I was typically getting around 42 on most trips. Shorter trips I could commonly pull off 50+. I tried plugging in an Alexa auto to the central console 12v port and found that I was getting significantly less efficient MPG. I unplugged Alexa after a day because I did not think it was worth the sacrifice, but I am still getting lower MPG. I haven't been able to top 40. Since that day, it just seems as though the car is more hesitant to kick into EV as I drive. 

 

Am I crazy? Has anyone else experienced issues from having an accessory that is plugged in all the time? Did I do something weird and how can I fix it?

 

Thanks! 

[jmcgliss]

Has your area experience a drop in temperature? Reduced tire pressure can affect mileage, and feel like more rolling resistance.

 

I followed suggestions on this forum to pump the stock Michelins to 48-50psi to optimize mileage and recently notice an mpg drop at my wife's last fill-up since it's cooled off here.

Edited October 1, 2019 by jmcgliss

[plus 3 golfer]

The Alexa device likely has minimal power draw such that its effect on FE will be noise (not measurable).  Cars don't like shorter trips and cooler temperatures for a lot of reasons including it takes longer to heat engine to operating temperature, normal operating temperature in cooler temps will likely be lower than in normal summer temps which decreases engine efficiency, cooler air is denser and increases aerodynamic drag, tires lose about one psi per 10 F drop in temperature.  A 5% change in FE at 42 mpg is 2.1 MPG which seems like a big change.  Wait until winter temperatures hit. ;)