Effects of Rain on Energy Consumption

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campfamily

Well-known member
Joined
Apr 21, 2015
Messages
457
Location
Southern California
So it's been a while since we've had any significant rain here in Southern California, but over the past month or so, we've been catching up. And, I've noticed that my energy consumption has gone up by a bit more than 10%. I know that you east coast / mid west guys are probably laughing at me right now, given the range knock-down you guys see during a "real" winter, but wanted to float (get it???) a theory out there. Yes, I know that drivers typically use the heater more when it's raining, since it is usually colder and you need to run the defroster more, but I've been trying to minimize, even eliminate using those, and I've still seen a jump from about 245 wh/mi to about 270 wh/mi, over the last 1,000 miles or so.

Just wondering if anybody has ever done a study on the effects of rain on vehicle energy useage....wouldn't matter if it's an electric or ICE vehicle. Seems to me that there is higher rolling resistance (harder to roll a wheel through water than dry pavement), and higher air resistance (the thousands of rain drops hitting the car must be harder to push through than dry air), all of which should increase energy useage. What do you guys think, anything to my theory?

Keith
 
yes more energy is used pushing the car through water but I bet your defroster use far outweighs the extra drag from wet roads (unless every road you're driving down has 1" or more of water on it all the time).

Simply running the defroster for a few minutes can remove several miles of range (and I'm not talking about the GOM value).
 
jmueller065 said:
yes more energy is used pushing the car through water but I bet your defroster use far outweighs the extra drag from wet roads (unless every road you're driving down has 1" or more of water on it all the time).

Simply running the defroster for a few minutes can remove several miles of range (and I'm not talking about the GOM value).

Yes, I am aware of that. So, I've been very conscious of watching my energy useage screen, and for those short moments I use the defroster, having the temp turned down enough so that the "Climate" bar doesn't show I'm using any energy (sometimes can't do that, no matter how far to the left I turn the dial). Compared to my normal climate control useage, which is "set and forget", with pre-heating at home on cold mornings. Maybe even those short bursts are using more energy than I was thinking. If so, can't imagine what would happen if I just let the defroster run.

Bottom line, yet another reason to appreciate living in a region where bad weather isn't really bad, it's just a bit annoying!!

Keith
 
The window defog/frost setting runs both the AC and the heat to dehumidify the air it blows on the windshield which will use a lot of energy. I got by recently when I needed all the range I could muster by using a cheapie 12V heater/fan that I set on the dash to keep the windshield clear. You could experiment with a fan blowing on the window to see f it will keep it defogged.
 
Yes the biggest effect is the AC and Heater. There are all kinds of crazy theories about rain and air density, and pushing the car through those things, and that they make some kind of difference. The lions share is the temperature. Sadly, not much you can do about rain.
 
I'm not around my FFE but what is the instant power output on flat ground at 60mph? That should tell you how much more power it takes in rain. Compare wet to dry.
 
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