Possible battery issue?

[TankoftheNorth]

I traveled 290 miles from the twin cities to Madison Wisconsin for the holidays and had planned to stop at one Super Charger on the way to complete my trip. I kept EAP/TACC at 77 the duration of the trip. Unfortunately, I ended up having to stop at two Super Chargers to make it the entire way.

So on the way back home I decided to track my miles by taking screen shots when I started my trip back and at each stop I made to charge and also keep my speed at 72 mph. The speed limit is a 70. Like my trip to Madison, Wisconsin, I had to stop twice on my way back to the Twin Cities, Minnesota. Here are the trip details on the way back. Also, I have an LR AWD.

I left Madison with 193 miles range. It was 89 miles to the Mauston (Wisc Dells) Super Charger. So my battery should have been at 104 (193-89 mile trip) when I arrived, but it was at 69 miles. So at 72 mph I lost 35 miles on an 89 mile trip. That's a 40% mile loss from all freeway driving.

In Mauston, I charged 229 miles back up to 298. The next Super Charge station was 103 miles away in Eau Claire, Wi. So my batter should be at 195 (298-103 mile trip) when I arrived, but it was at 157 miles. So again at 72 mph I lost 38 miles on a 103 mile trip. Again nearly a 40% mile moss.

Unfortunately, on my last leg of the trip I forgot to screen shot my miles when I arrived, but I know it was about the same.

The other problem I had was the rate my car charged at. The last half dozen Super Charges I have not been able to charge over 110 mi/hr or 30kW. Even when I have been the only car at the station. I've tried moving my car to a different stall each time, but it doesn't make a difference. It's also been making a large hum when it charges, and I'm not sure if that's new or if it's something I'm only noticing now that I'm more focused on the battery. It's really annoying that it has sometimes taken over 1.5 hours to charge my batter back up to 80%.

Does this all seem normal, and are other people in the Midwest experiencing the same issues now that it's colder? Or could something else be going on with my battery?

 

[ckoval7]

I traveled 290 miles from the twin cities to Madison Wisconsin

Cold weather greatly affects your range!
I put the route into A Better Routeplanner and it showed two supercharger stops for an AWD M3 leaving home with 90% charge and 30F outdoor temp.

As for the charging, if your battery is cold, the charging speed will be limited.

 

[TankoftheNorth]

Cold weather greatly affects your range!
I put the route into A Better Routeplanner and it showed two supercharger stops for an AWD M3 leaving home with 90% charge and 30F outdoor temp.

As for the charging, if your battery is cold, the charging speed will be limited.

Define what a cold battery is. Because I was charging after driving for over an hour at each stop of my trip, yet was unable to charge over 30kW. So my battery should have been warm when it was being charged.

Also, thanks for linking me to that site. I haven't seen it before!

 

[ckoval7]

Define what a cold battery is. Because I was charging after driving for over an hour at each stop of my trip, yet was unable to charge over 30kW. So my battery should have been warm when it was being charged.

Also, thanks for linking me to that site. I haven't seen it before!

You start losing regenerative braking when the battery temp is below 55F. Li-Ion cells have a negative temperature coefficient, which means as the temperature drops, the cell resistance goes up. Telling us what the weather was like and how warm you like the cabin would be pretty helpful!

Usually driving warms the pack up and you get all that back, but I can imagine a scenario where you're keeping a steady speed on the highway and it's cold enough outside that you're not pulling enough power to keep the battery warm. I don't know what the terrain is like on that route, but if I had to guess, I'd think it's pretty flat in that part of the country.

 

[mswlogo]

193 - 69 = 124 (Miles That the Battery Said were used for the trip)

89 (Miles actually driven)

89/124 = 0.717 Efficient (Miles Driven / Miles Used On Battery)

1.0 - 0.717 = 0.283 (You lost around 28%)

If Miles Driven equals Battery Miles Used it would be 100% Efficient

I leave the 2nd problem as home work for the OP.

 

[TankoftheNorth]

193 - 69 = 124 (Miles That the Battery Said were used for the trip)

89 (Miles actually driven)

89/124 = 0.717 Efficient (Miles Driven / Miles Used On Battery)

1.0 - 0.717 = 0.283 (You lost around 28%)

If Miles Driven equals Battery Miles Used it would be 100% Efficient

I leave the 2nd problem as home work for the OP.

Thanks, I wasn't sure about how to calculate the efficiency. I went with 35 miles lost on a 89 mile trip = 35/89. I think the problem is the wording I used. But you are correct, for efficiency I should have calculated the miles used versus the miles that should have been used (124 vs 89).

That doesn't change the fact that over an 89 mile trip I lost 35 miles of extra range over the actual trip distance.

 

[mswlogo]

Thanks, I wasn't sure about how to calculate the efficiency. I went with 35 miles lost on a 89 mile trip = 35/89. I think the problem is the wording I used. But you are correct, for efficiency I should have calculated the miles used versus the miles that should have been used (124 vs 89).

That doesn't change the fact that over an 89 mile trip I lost 35 miles of range.

Yeah, you lost 35 miles out of 124 (of battery) which is also 28%

 

[TankoftheNorth]

You start losing regenerative braking when the battery temp is below 55F. Li-Ion cells have a negative temperature coefficient, which means as the temperature drops, the cell resistance goes up. Telling us what the weather was like and how warm you like the cabin would be pretty helpful!

Usually driving warms the pack up and you get all that back, but I can imagine a scenario where you're keeping a steady speed on the highway and it's cold enough outside that you're not pulling enough power to keep the battery warm. I don't know what the terrain is like on that route, but if I had to guess, I'd think it's pretty flat in that part of the country.

The weather outside was around 32-35. I keep the car around 68-70, and mostly keep it shut off once it reaches that. Also, it's a fairly flat drive the entire way.

 

[TankoftheNorth]

Yeah, you lost 35 miles out of 124 (of battery) which is also 28%

Wording it this way is misleading. 124 miles is what was deducted from my original range. It is how we get to the 35 miles lost. What is more important is to know the actual distance traveled, which is 89 miles. I lost 35 miles from the original estimate of an 89 mile trip. We are not disagreeing with the numbers, we are just verbalizing them differently

 

[mswlogo]

Wording it this way is misleading. 124 miles is what was deducted from my original range. It is how we get to the 35 miles lost. What is more important is to know the actual distance traveled, which is 89 miles. I lost 35 miles from the original estimate of an 89 mile trip. We are not disagreeing with the numbers, we are just verbalizing them differently

It's not that misleading. It's all how you look at it.

The battery said you should have gone 124 miles but you only went 89 so you lost 35 (out of the 124 miles you should have attained).

I like to work it out as actual/estimated to keep it clear in my head.

 

[TankoftheNorth]

It's not that misleading. It's all how you look at it.

The battery said you should have gone 124 miles but you only went 89 so you lost 35 (out of the 124 miles you should have attained).

I like to work it out as actual/estimated to keep it clear in my head.

I agree, it's how you look at it. We're describing the same thing but in different ways. And I appreciate you pointing out a better way to look at it!

 

[bsietz]

One thing that may help you avoid taking screenshots is to look at a logging utility for your Tesla. I use TeslaFi which will track drives, charges, costs, etc. It logs lots of data for each drive - power, battery, speed and temp over the entire drive:

TeslaFi gives you a two week free trial - if you decide to give it a try - use bsietz as a referral code and you will get an additional two weeks of your trial!

Enjoy
-Brian

 

[devilmountain]

I went to my sisters house on Christmas Eve. I left my house with 100 percent charge. I had my wife and two children in the car along with gifts and food. It was about 51 degrees out with medium to heavy rain. Heater was set to 71 degrees and my wife had her seat heater on.The total round trip mileage was about 200 miles. I drove with EAP on and set my speed for 70 and my wife drove with TACC on the way home with speed set for 70. When we arrived home we had 21% charge left. This exact same trip in October with speeds in the 75mph range we arrived home with 34% range. Weather makes a huge difference.

We drove to LA in nearly similar weather at the beginning of the month. We drove at 77mph and when we arrived at our first supercharger which was 200 miles away we had 12% battery.

Weather and driving speed makes a big difference in range.

 

[hdAge]

I left Madison with 193 miles range. It was 89 miles to the Mauston (Wisc Dells) Super Charger. So my battery should have been at 104 (193-89 mile trip) when I arrived, but it was at 69 miles. So at 72 mph I lost 35 miles on an 89 mile trip. That's a 40% mile loss from all freeway driving.

I would never rely on the battery range that displays the number of miles remaining. Always use the Energy consumption meter which is much more accurate depicting the current driving conditions, you can also toggle between a 30 mile average and current driving condition. I learned it during my first road trip and since then with the Energy consumption meter, I now have a very good idea on the range.

It's really annoying that it has sometimes taken over 1.5 hours to charge my batter back up to 80%.

This is certainly not normal, but as others mentioned the cold temperature can affect the charging time. I would try charging few more times and keep track of the charging time and see if it improves.

 

[mswlogo]

I would never rely on the battery range that displays the number of miles remaining. Always use the Energy consumption meter which is much more accurate depicting the current driving conditions, you can also toggle between a 30 mile average and current driving condition. I learned it during my first road trip and since then with the Energy consumption meter, I now have a very good idea on the range.



This is certainly not normal, but as others mentioned the cold temperature can affect the charging time. I would try charging few more times and keep track of the charging time and see if it improves.

He wasn’t trying to see what his current real time range was (which energy chart is great for). He just used the battery range to calculate efficiency for the whole trip. The battery gauge read out on the main screen IS your FUEL gage. It just so happens to be units of EPA rated range of the car.

The energy chart USES the FUEL gauge as well and factors in your current burn rate kw/mi for a better real time range estimate. The energy chart isn’t that useful for calculating efficiency for a long trip.

Apples and oranges. What he did was fine. Just a slight math error.

 

[ewoodrick]

You've combined a number of factors in such a way that your range is expected to be dismal.

• Your location shows as "The North" so that says cold, and your indications that temperatures were at freezing confirms that. You can probably take away 20% or more just for that.
• Turning the AC off once it reaches temperature doesn't do any good, you've already used the energy. But that's not a big factor.
• You didn't mention which car you have, but if you don't have the 18 inch wheels with the covers on, you can subtract another 5-10%.
• Going 72 mph also subtracts another 20-30%. Once you start to go above 50 mph, you are going to drop below the rated range.

To get a much better estimation of range, look at the numbers on the Energy page. It shows something much closer to reality than the number near the speed.

 

[duanra]

I was on the road today, mid range with 18 inches wheels. It was -10c. Then the outside temp started to drop. I noticed that the destination percentage was dropping by approx 1 percent per celsius degree lost.

 

[TexasEV]

The battery said you should have gone 124 miles but you only went 89...

That’s not what rated range means. It’s not how far you “should” have gone, it’s how far the car would go on the EPA test cycle, under the conditions of the EPA test including temperature.

 

[animorph]

Use a trip planner like EVTripPlanner or ABetterRoutePlanner to see how many rated miles your trip will use, and the fastest set of Supercharger stops. Your "loss" seems very normal.

The slow charges do seem unusual if the car had not been sitting around getting cold before charging.

 

[mswlogo]

That’s not what rated range means. It’s not how far you “should” have gone, it’s how far the car would go on the EPA test cycle, under the conditions of the EPA test including temperature.

When I say “should” I’m implying how far EPA says it “should” go. That is the reference every is using. How much worse than the EPA rating or how much better. What other reference are you going to use?

It is the only fuel gauge we have and it’s in units of EPA rating. ~310 miles is a full tank on an LR battery.

I have no problem getting a little better than EPA when I don’t need heat. EPA numbers are reasonable.

You could argue he should get exactly what he got too