Terrible Efficiency in the Rain?

[mpshizzle]

I've noticed there's always a HUGE drop in efficiency when I'm driving through the rain.

Generally speaking (depending on terrain and how heavy my foot is) I will get 2.7-3.3 mi/Kwh

But I feel like my efficiency tanks when there's rain. Last night during a rain storm I was getting like 2.0mi/Kwh. My first thought was battery heater. But it was still in the 70s-80s outside. The only other thing I can think of is the windshield wipers or some aerodynamics thing..

Anyone else notice this?

Sponsored

 

[GoGoGadgetMachE]

I've noticed there's always a HUGE drop in efficiency when I'm driving through the rain.

Generally speaking (depending on terrain and how heavy my foot is) I will get 2.7-3.3 mi/Kwh

But I feel like my efficiency tanks when there's rain. Last night during a rain storm I was getting like 2.0mi/Kwh. My first thought was battery heater. But it was still in the 70s-80s outside. The only other thing I can think of is the windshield wipers or some aerodynamics thing..

Anyone else notice this?

I haven't noticed but I haven't paid attention to it, either.

in general rain hurts efficiency ( friction - Does a car consume more fuel when it's raining? - Physics Stack Exchange ). but it seems to be debated how much.

that said, I wonder, was it particularly windy as part of the storm? any headwind would be a problem for much more obvious reasons.

 

[RedStallion]

I've noticed there's always a HUGE drop in efficiency when I'm driving through the rain.

Generally speaking (depending on terrain and how heavy my foot is) I will get 2.7-3.3 mi/Kwh

But I feel like my efficiency tanks when there's rain. Last night during a rain storm I was getting like 2.0mi/Kwh. My first thought was battery heater. But it was still in the 70s-80s outside. The only other thing I can think of is the windshield wipers or some aerodynamics thing..

Anyone else notice this?

Is it at highway speeds? It can be the water on the road, it can be the energy needed to push the water droplets. Since EVs are so optimized for efficiency, any such thing can have a big effect. It's rarely raining here, so I can't experiment with that.

 

[mpshizzle]

Is it at highway speeds? It can be the water on the road, it can be the energy needed to push the water droplets. Since EVs are so optimized for efficiency, any such thing can have a big effect. It's rarely raining here, so I can't experiment with that.

Yes, this is highway speeds. I hadn't thought of that either. That would make sense to me. Perhaps if I get drag slicks it'll take less energy to push water out of the way... That sounds safe! ?

 

[pt19713]

Water droplets increase energy consumption due to increased air resistance, in addition to the extra energy needed to displace the water on the surface.

 

[AZBill]

It is fairly well known in the EV world that rain reduces efficiency because of the increased rolling friction. Snow also has the same effect. The tires end up pushing the water and snow out of the way, thus using up energy.

 

[mpshizzle]

It is fairly well known in the EV world that rain reduces efficiency because of the increased rolling friction. Snow also has the same effect. The tires end up pushing the water and snow out of the way, thus using up energy.

Well then I guess I just let my noob show ?

 

[Motomax]

Happens to every car, the wider the tires the more impact rain will have as well. Haven’t you ever felt your car slow down when you hit a really wet section of road?
Add the electrical drain of the wipers and the heater trying to remove humidity and loses just compound.

 

[llinthicum1]

I can see where road conditions affect performance. But the electrical drain from the windshield wipers?????????? Does playing the radio affect performance?????? Can the defroster be run without affecting performance?????? What else?????

 

[SnBGC]

I've noticed there's always a HUGE drop in efficiency when I'm driving through the rain.

Generally speaking (depending on terrain and how heavy my foot is) I will get 2.7-3.3 mi/Kwh

But I feel like my efficiency tanks when there's rain. Last night during a rain storm I was getting like 2.0mi/Kwh. My first thought was battery heater. But it was still in the 70s-80s outside. The only other thing I can think of is the windshield wipers or some aerodynamics thing..

Anyone else notice this?

Yes. I have observed similar effects with inclement weather. It has to do with the energy required for the tires to pump water through the treads and I suppose some parasitic resistance due to suction as well.

It doesn't rain here much but we had our first real monsoon storm a while back and it rained most of the night and was still raining when I left for work. Normally my car would estimate around 275-280 miles on the GOM with 90% SOC but that day is said 204 miles. I suspect it somehow knew it was raining and figured that into the calculation. Not positive about that though.....
I ended up at work (22 miles away) with about 235 miles on the GOM so it was super weird to see my estimated range increase while my charge percentage decreased.

That was a fun drive to work that day....

 

[BMT1071]

I can see where road conditions affect performance. But the electrical drain from the windshield wipers?????????? Does playing the radio affect performance?????? Can the defroster be run without affecting performance?????? What else?????

Literally every electrical accessory on the car draws its power from one of the batteries. The HVB maintains the charge of the LVB. So in short, anything you use reduces the range. It may be an incredibly small reduction, but a reduction nonetheless.

 

[JamieGeek]

Keep in mind that if its raining your defroster may also come on--especially if you have it in automatic with the e-heat on. That will chew through range pretty good.

 

[JoeDimwit]

I can see where road conditions affect performance. But the electrical drain from the windshield wipers?????????? Does playing the radio affect performance?????? Can the defroster be run without affecting performance?????? What else?????

Yes. Enough to make a real difference? Not so much.

 

[breeves002]

I would speculate the biggest cause of efficiency drop in rain is defrost causing the heater to come on. I’m sure there is some reduction in efficiency, but it probably is 10% max. The extra chunk has to be from the heater. These have some fancy defrost algorithms to keep the windshield from fogging up before it does and you request defrost.

 

[JoeDimwit]

I would speculate the biggest cause of efficiency drop in rain is defrost causing the heater to come on. I’m sure there is some reduction in efficiency, but it probably is 10% max. The extra chunk has to be from the heater. These have some fancy defrost algorithms to keep the windshield from fogging up before it does and you request defrost.

That is likely the second largest drain… I am going with rolling resistance being #1.

Sponsored