[JoeReal]

My EV Range display is normally 60 miles when I leave for work in the morning. My commute is 32 miles, 25 miles of freeway (65 mph speed limit) and then 7 miles of city streets (35-45 mph speed limits). I drive early mornings, no traffic. And when I get to the office, I still have 30 miles left on my EV Range. But whenever it rains on me all the way, the EV Range left would be 23 miles, and everybody on the freeway slows down to 50-55 mph. If it is just a drizzle or only portions of the trips have rains, my remaining EV range could be between 24-28 miles.

I suspect that the rain hitting on the Volt has a massive weight piled against it, after all, water even when interspersed with air, as in rain, is still at least a couple of magnitudes denser than air.

Has anyone else noticed this rain penalty?

 

[no fumes]

I would happily give up some of my EV range for some of that rain here in San Diego!

 

[rhodomel]

I would happily give up some of my EV range for some of that rain here in San Diego!

Be careful of what you ask for. You might get it in deluge and sweep your Volt away... Flash flooding is in the forecast this winter for Southern California.

 

[ChiVolt]

Electric windshield wipers will deplete the battery more quickly. Some Volt owners use Rain-X to minimize use of windshield wipers.

 

[RePo]

The range loss comes from the pinwheel effect on the tires. If you were to take a wheel and rotate it fast in the open air, and then dip it into 1/2 inch of water it would become a pinwheel and throw hundreds of pounds of water per minute in all directions. Multiply that by 4 and you have your range loss in the rain. When you hit a deeper puddle you can actually feel any car decelerate and hear the water scrub the wheel well.

 

[Neromanceres]

Rain certainly does impact range though 7 miles seems a little steep. You might want to check to see if auto defog is turned off in your car. The higher relative humidity might be causing the auto defog to activate which can also consume a lot of energy.

 

[Insight Refugee]

Heavy rain would take the old Insight from 60ish MPG down to 45ish MPG on my regular commute. The Insight was especially susceptible to efficiency hits from wet roads because the rear wheels were offset from the front wheels. As a result, all four tires had to plow through the wet instead of the rears following in the furrow made by the fronts. This set up was great for aerodynamics, but horrible for wet roads.

Heavy rain does impact aerodynamics, but most of the efficiency hit is from the tires pumping water out of the way and the increased rotational mass.

 

[khalfyard]

I notice a large 'rain effect' on my Nissan Leaf. It's certainly real.

 

[Steverino]

Rain affects MANY things, most listed above.

Denser air = more energy required to move through it.
Windshield wiper = more energy required to move wipers.
A/C Defog = more energy required to dehumidify, plus turn the fan.
Tires = more energy required to move through the water.

Now replace the rain with the frozen version and you get an even greater loss, plus added loss for heating and stiffer lubricants.

 

[hellsop]

Rain affects MANY things, most listed above.

Denser air = more energy required to move through it.
Windshield wiper = more energy required to move wipers.
A/C Defog = more energy required to dehumidify, plus turn the fan.
Tires = more energy required to move through the water.

Now replace the rain with the frozen version and you get an even greater loss, plus added loss for heating and stiffer lubricants.

More likely to have headlights on.... And stiffer tires too.

 

[ampera_jed]

We have lots of rain in England, and on the forums here it's been discussed a lot. It's suggested the effect is due to a change in surface energy.

It's too big an effect for rain by mass being thrown around because you get it even when it's not raining and the roads are wet with only a thin layer of rain sitting on them.

You press your tyre onto the wet road and it's low surface energy. You pull the tyre up off the road the tyre has just dried off, and it's now high surface energy.

Basically, wet roads are 'sticky' when you try to peel the tyre off the road.

 

[JoeReal]

Thank you all!

My climate settings score was only -0.5. So my defogging didn't cost me much. I have rainx interior. Temperature was just about 61 deg F outside.

I only tap my windshield wipers once a while, I have rainx exterior.

I think this has to do primarily when the roads are wet from the pouring rain with the wet tires consuming more power as it turns, as a major factor. I noticed the rapid draw down of EV range in sections when there are some thin water film on the road and while vehicles are slow at about 50 mph. And the next big factor would be the pounding rain that the vehicle has to go against. The kinetic energy of those rain can be big, depending on the intensity of the rain and the speed that the droplets collide with the vehicle.

The windshield and defog are minor for my settings.
Tire pressure are normal.

 

[BAZINGA]

If you follow any motor sports that's all you hear, AERO. The slightest dent on a race car can affect it's performance. These new vehicles have been fine tuned in a wind tunnel. ANY disruption of the air flow will have an impact.

I just didn't think it would be 7 miles of EV range. But on my 13 I applied Rain-X on all my glass to include the headlights.

 

[Insight Refugee]

If you follow any motor sports that's all you hear, AERO. The slightest dent on a race car can affect it's performance. These new vehicles have been fine tuned in a wind tunnel. ANY disruption of the air flow will have an impact.

I just didn't think it would be 7 miles of EV range. But on my 13 I applied Rain-X on all my glass to include the headlights.

I'm not saying there is no aerodynamic impact from rain, but I think it is less than the impact from the wheels moving water around. I would take at least a 10% hit driving around town where the speeds were not high enough for much of an aerodynamic impact. That drop in MPG would be persist even if it had stopped raining and I was just driving on wet roads.

 

[Triarius]

In addition to what everyone wrote above, it is notable that aircraft using so called "laminar flow" airfoils see a much greater performance degradation in rain and other conditions which cause surface contamination than types with more conventional airfoils. Laminar flow airfoils are considered to be otherwise more advance and result in significantly more efficient operation. I wonder if this effect is also noticeable in automotive aerodynamics. Our low drag coefficient cars might be more susceptible to aerodynamic perturbations from something as small as a water droplet.

 

[Barry]

I think aero is more critical in motor sports because the speeds are so much higher, and aero drag increases with the square of speed.

I definitely notice the range loss on my Gen 1. Never noticed on an ICE car, but maybe that is because it is normally harder to track efficiency on a daily basis.

 

[Insight Refugee]

I definitely notice the range loss on my Gen 1. Never noticed on an ICE car, but maybe that is because it is normally harder to track efficiency on a daily basis.

I think it's just a numbers/perception issue. On the Insight, a 10% hit on MPG was noticeable because (a) the car could easily get 60+ MPG and 10% of 60 is more noticeable than 10% of 25; and (b) the Insight had a better than average MPG display to track this metric.

On the Volt, losing 6 miles of range is very noticeable when you are playing with only 60 miles to begin with. On an ICE car with 350 miles of range, the percentage of miles driven in heavy rain over the course of an entire tank of fuel would usually be too low to make a detailed or accurate observation.

 

[quirkySquirt]

Wow, learned a lot from this thread. It all makes sense, though, how rain requires more energy to turn a wheel and for the same wheel to push the rain water out of the way. Also never really thought of the wipers eating energy too, always focused on the defogger energy consumption. Will have to pay attention to energy consumption when I have the wipers on and off next time.

 

[alfon]

Living here on the coast in northwestern Oregon rain is the norm during at least 7 months of the year. Dry roads will normally give you at least 10% more miles on electric and more mpg's on gas. This applies for our 2016 Volt and our 2010 Prius. Rain with water and standing water on the roadway can even lower it by 15%.

In summer warm weather dry roads our 2016 Volt was getting about 60-65 miles on electric. Now 50- 55 miles is the norm. Our 2010 Prius mpg's has dropped to 48-52 mpg from 57-60 mpg during the summer.

Also winter blended gas will also lessen your mpg on gas which has less btu's per gallon than summer blended gasoline.

 

[DA\Volt]

A moderate rain here in Los Angeles this morning. Pretty wet for most of my 19 mile commute through the Newhall Pass. Was dry going home. End of the day I saw absolutely zero impact on EV guessometer or number of kWh used. I did turn off auto headlights and climate control other than the fan.

Speaking of RainX, I took this quick video this morning to share in a different thread about poor visibility out the back window of the 2017 Volt, but I'll share it here instead.

With RainX on the rear window and front window, visibility perfect out both and rear view mirror. Despite a good downpour, never needed to use the wipers. I love that stuff.

https://youtu.be/zVbm8_5kC8I


Sent from my Nexus 6P using Tapatalk