Battery efficiency in rain

Joined
Jan 12, 2019
Messages
11
Location
Mount Laurel, NJ
Tesla Owner
Model 3
Country
Country
#1
Did anyone experience battery degradation in rain. I saw about 40 percent degradation in rain. The car going on AP at 70mph for the most part. With wipers on high. Oh yeah and the auto wiper isn't good at all. Needs a lot of work still. It got me worried. I started at 140mi battery and when I finished my 60mile drive the battery was at 38 miles. Same thing happened on the way back. It was showing 360 Watt hours/mile. Should I be worried?
 

MelindaV

☰ > 3
Moderator
Joined
Apr 2, 2016
Messages
7,436
Location
Vancouver, WA
Tesla Owner
Model 3
Country
Country
#2
1) It takes more to propel the car across wet pavement
2) there is more air resistance when there is rain falling
3) 360Wh... you need to hit about 240 to meet the rated range. This is in large part the 70mph. Assume you also had the hvac on, plus the 1&2 mentioned above.
4) the power to operate the wipers is not worth even adding into the energy used.

Do the same drive on dry pavement at 70mph, same temperature, with the same hvac settings and you can see what the rain conditions contributed.
 

JasonF

Well-Known Member
Joined
Oct 26, 2018
Messages
275
Location
Orlando FL
Tesla Owner
Model 3
Country
Country
#4
I've noticed that all batteries will diminish faster as the state of charge gets lower. So if you're close to running out of battery power, you're more likely to experience a sudden drop in range. Cell phones and tablets do that, and the many EV's that Bjorn Nyland has driven seem to do that as well. Low state of charge plus higher than normal current draw is a recipe for disaster.
 

Cubs15

New Member
Joined
Feb 10, 2019
Messages
3
Location
Menlo Park
Tesla Owner
Model 3
Country
Country
#5
I have been having the same problem. Drove yesterday in very rainy conditions, outside temps in low 50s and my range was terrible. Turned into a 20 mile drive at avg of 370 wh/mi. Granted I have a performance version with 20 in tires, but my efficiency has generally been bad as i am averaging 325 wh/mi over my first 3k...thars with full regen and non aggressive driving intended to optimize for range.
 

JasonF

Well-Known Member
Joined
Oct 26, 2018
Messages
275
Location
Orlando FL
Tesla Owner
Model 3
Country
Country
#7
I just took a 20 mile drive in very light sprinkle, and averaged 270 wh/mi. Normally I get between 250-260, and I don’t even try that hard.
 

Cubs15

New Member
Joined
Feb 10, 2019
Messages
3
Location
Menlo Park
Tesla Owner
Model 3
Country
Country
#8
JasonF: Can you share which model (rwd/awd) and tires you have? I know efficiency is better on aero tires with rwd, but I've been surprised how much worse my range has been with 3P +20in wheels.
 

Ed Woodrick

Well-Known Member
Joined
May 25, 2018
Messages
365
Location
Atlanta, GA
Tesla Owner
Model 3
Country
Country
#9
Just to be clear, battery efficiency doesn't change in the rain. That's the cars efficiency.
Batteries have charging and capacity issues when there are temperature extremes.

Rain is only thousands of little drops pushing you the wrong direction
 

JasonF

Well-Known Member
Joined
Oct 26, 2018
Messages
275
Location
Orlando FL
Tesla Owner
Model 3
Country
Country
#10
JasonF: Can you share which model (rwd/awd) and tires you have? I know efficiency is better on aero tires with rwd, but I've been surprised how much worse my range has been with 3P +20in wheels.
RWD long range with de-covered aero wheels, like it says in the footer.
 

ADK46

Top-Contributor
Joined
Aug 4, 2018
Messages
430
Location
Adirondacks, NY
Tesla Owner
Model 3
Country
Country
#14
In principle, you can figure out the gallons/minute of water that must be displaced and accelerated to some velocity (or maybe just use the contact patch pressure, about the same as tire pressure). That will equate to substantial power - picture a pressure washer. Or think of it this way: your tires have to squeegee about 5280 square feet of wet road per minute. That's like a wet basement every 30 seconds.

Let's not unduly malign our wonderful batteries - this is not "battery degradation". We would never call this "gasoline degradation" in ICE cars!