V10 and Battery "Degradation"

[Big Earl]

I don’t know how many times I can point the Model 3 folks to the several-hundred-page long thread in the S forums.

This issue impacts ALL Tesla batteries.

Go do some reading if you want, or don’t. Some people will always bury their heads in the sand I guess.

They are different issues.

On Model S & X, Tesla limited the top end of the battery by lowering the maximum voltage. They also slowed down maximum charge rates.

On Model 3, Tesla appears to have limited the bottom of the battery by raising the minimum voltage. Charge rates appear to be unaffected.

 

[MP3Mike]

On Model 3, Tesla appears to have limited the bottom of the battery by raising the minimum voltage. Charge rates appear to be unaffected.

And we don't know if they have actually limited it, or if they have just hidden/disguised it. (Can you drive past 0 now?)

 

[rayfound]

And we don't know if they have actually limited it, or if they have just hidden/disguised it. (Can you drive past 0 now?)

Right, it could be as simple as basically changing where the "low fuel" light activates.

 

[UKNOWINVU2]

LR RWD - 32,000km (19,883miles)
Since range increase a 90% charge would always show me 470km. (292miles)
Right after V10 a 90% charge showed 455km. (283miles)
As of this morning a 90% charge is showing 429km. (267miles)
I was at the service center last night* and asked "why is my rated range dropping". They told me "with the new software updates that range is now based on your driving habits as it learns the way you drive and predicts your range accordingly". Tesla recommended I change my display to battery percentage.

 

[AlanSubie4Life]

They told me "with the new software updates that range is now based on your driving habits as it learns the way you drive and predicts your range accordingly". Tesla recommended I change my display to battery percentage.

It is easy to prove/disprove this (likely false) claim by the service center. Note initial rated miles, immediately do a drive of significant distance (say, use more than 15kWh), and then immediately note the trip meter data (Wh/mi and traveled miles) and the final rated miles. Calculate (Wh/mi * Distance traveled) / (Rated miles used). If it is ~223Wh/rmi, then nothing has changed in the treatment of the battery gauge (this is the LR RWD discharge constant).

It is very likely that the display is showing that you have lost 28 rated miles from your full charge (324-296), which means you have 6.25 fewer kWh available (28rmi*223Wh/rmi), as measured by the trip meter, at a full charge, as compared to when you had 292 rated miles at 90%.

This may of course be a temporary issue (it may not be actual battery degradation). There are various possible reasons for the car to decide to make less energy available at a full charge.

But it is very likely that the service center is wrong about the driving habits. Tesla has never treated the battery gauge rated miles that way and it seems unlikely that they will change that philosophy (which is good). Rated miles have always been a simple, direct measure of how much energy you have available.

 

[earthwormjim]

So update after doing a 3rd 100% charge, to 10% discharge and back to 100% charge. I'm left with 227 miles (100% charge) of displayed range after doing this on my SR+. Consumption meter shows that 100% down to 17% used 38kwh of energy, recharge display showed ~41kwh. This was not done in one drive, but over two days. This works out to a hypothetical battery capacity of 45.7 kwh. The car did not use 5kwh while sitting over night, lost at most 2% capacity according to battery % displayed.

Something definitely seems up with the battery, all 3 rounds of full charging and heavily discharging all work out to yield a theoretical battery capacity of 45kwh +/- 1kwh. Quite a bit lower than expected for an SR+, and certainly can't be accounted for by rounding errors.

Doing this has netted me 7 miles of increased displayed range, after being stuck at exactly 220 miles of range post V10 update. I suppose that's an improvement, but it definitely seems like I have lost capacity in some way. Debating setting up a service appointment. I think I'll wait a few more weeks, see what happens. Car has 6076 miles now, owned it since early June 2019.

Please don't reply with stating the range meter in miles doesn't mean actual miles you can drive, that's not how I'm using it. It is a meter of battery capacity, based on the wh/mi constant Tesla uses.

 

[AlanSubie4Life]

Consumption meter shows that 100% down to 17% used 38kwh of energy, recharge display showed ~41kwh. This was not done in one drive, but over two days.

If you had done a continuous drive to 17% your trip meter would have read ~39.4kWh (188.5rmi * 209Wh/mi). So you lost 1.4kWh while parked.

Your recharge event is within 1% of expected (0.83*227rmi*219Wh/mi = 41.3kWh).

Overall you have 13rmi*209Wh/rmi = 2.7kWh less energy available (to be used on trip meter) at 100%, above zero rated miles remaining, than you did originally.

 

[earthwormjim]

If you had done a continuous drive to 17% your trip meter would have read 39.4kWh (188.5rmi * 209Wh/mi). So you lost 1.4kWh while parked.

Your recharge event is within 1% of expected (0.83*227rmi*219Wh/mi = 41.3kWh).

Overall you have 13rmi*209Wh/rmi = 2.7kWh less energy available than you did originally.

Lost about 2% displayed battery (energy display mode) overnight, so that works out closely.

So I'm sitting at between 5-10% capacity lost, somewhere in that neighborhood (closer to 5%).

 

[MP3Mike]

I suppose that's an improvement, but it definitely seems like I have lost capacity in some way. Debating setting up a service appointment.

And what would you expect them to do? You aren't below the 70% of capacity that is warrantied...

 

[earthwormjim]

And what would you expect them to do? You aren't below the 70% of capacity that is warrantied...

See if a rebalance is needed. Hence waiting for a while before I do, the BMS might fix this issue over time. I'm seeing other people with the LR models regaining range after a big dip right when V10 came out.

 

[MP3Mike]

See if a rebalance is needed.

Which you have already done...

 

[AlanSubie4Life]

So I'm sitting at between 5-10% capacity lost, somewhere in that neighborhood (closer to 5%).

Yes, currently 5.4% of your available energy above zero rated miles has been lost. I would suggest not wasting your time with the service center for now. It's possible this situation could change for the better. No one knows.

 

[earthwormjim]

Which you have already done...

Correct, and I still have at least 5% range loss in 3 months of ownership. So the service center can tell me in person that that is "normal" or not. They can actually test battery voltage, and see if there is anything actually wrong. If the cells aren't charging to full capacity voltage, then it's software. If they are fully charging, then it's degradation.

But I will wait a while. It is a very telling coincidence that this occurred the day after I updated to V10.

 

[ElectricOrgan]

I'm pretty fed up trying to figure out how to make sense of the range issues. There are the issues of consumption while driving, but then there is unaccounted for consumption when not driving. Trying to track all of this is a bear. Bottom line is the car will use a bunch of energy no matter what you do. It is important to keep the car charged any time you aren't using it and plan your trips carefully.

People will say you only need to use the in-car trip planner, but that is not true. My car will tell me I can reach my destination with 5% or less remaining and not even suggest a charging stop. My destination is a minimum of 10% away from a Supercharger. Obviously I'm not going to ignore that issue even though the car does. It also has no ability to plan trips with more than one stop. It's a poor trip planning tool.

 

[AlanSubie4Life]

It also has no ability to plan trips with more than one stop. It's a poor trip planning tool.

That's true. It does require you to basically pick how you want to get to your destination. I haven't found it good at picking the optimal Supercharger if there are a lot around (often the case in California). The car wanted me to stop in Barstow rather than Yermo, inexplicably. ABRP is better at that task. However, the estimates in the car do tend to be fairly good once you decide how you're going to get there.

I'm pretty fed up trying to figure out how to make sense of the range issues.

There's not that much to work out. It's a very simple formula to determine what happened to your rated miles. It is true that the car uses a lot of energy while parked, even if you aren't using Sentry/Summon Standby. That's not really an issue for range since when you care about range your car will not be sitting parked for any significant time, in general. (There are obviously important exceptions to this.)

 

[PhantomX]

I'm pretty fed up trying to figure out how to make sense of the range issues. There are the issues of consumption while driving, but then there is unaccounted for consumption when not driving. Trying to track all of this is a bear. Bottom line is the car will use a bunch of energy no matter what you do. It is important to keep the car charged any time you aren't using it and plan your trips carefully.

People will say you only need to use the in-car trip planner, but that is not true. My car will tell me I can reach my destination with 5% or less remaining and not even suggest a charging stop. My destination is a minimum of 10% away from a Supercharger. Obviously I'm not going to ignore that issue even though the car does. It also has no ability to plan trips with more than one stop. It's a poor trip planning tool.

That's one thing that I have start to realize. The indicated range is good for planning one continuous trip, but it is very poor in predicting range when multiple trips are required when there are no charging options in between. An extreme of this is what I just experienced yesterday, where I had came back to my parked car at the airport after a 2-day trip, and it lost 16% of the charge. It's good thing that I didn't have to drive much yesterday, but it could have throw off my plan had I needed to add an hour of charging trip since there are no superchargers within my errand routes yesterday.

And I got to say that coming from BMW i3, this is a major surprise. I had left the i3 without charging for over a week while we were on vacation, and we came back with only 1% lost in range. Wonder what would happen to Model 3 in that scenario.

 

[AlanSubie4Life]

a 2-day trip, and it lost 16% of the charge.

Turn off Sentry and Summon Standby mode. The drain is still poor without those features, but nowhere near 8% per day.

 

[PhantomX]

Turn off Sentry and Summon Standby mode. The drain is still poor without those features, but nowhere near 8% per day.

I was surprised as well. I do typically see 3 to 4% drain throughout the day as my car sits in our work parking lot, so I guess extrapolating that to 50 hours may explain the 16% drain. I did turn off Summon Standby yesterday after seeing this battery drain, but I am keeping Sentry on just so I don't miss any footage when I really need it.

 

[AlanSubie4Life]

I was surprised as well. I do typically see 3 to 4% drain throughout the day as my car sits in our work parking lot, so I guess extrapolating that to 50 hours may explain the 16% drain. I did turn off Summon Standby yesterday after seeing this battery drain, but I am keeping Sentry on just so I don't miss any footage when I really need it.

Sentry used about one mile per hour last I checked.

 

[ElectricOrgan]

That's true. It does require you to basically pick how you want to get to your destination. I haven't found it good at picking the optimal Supercharger if there are a lot around (often the case in California). The car wanted me to stop in Barstow rather than Yermo, inexplicably. ABRP is better at that task. However, the estimates in the car do tend to be fairly good once you decide how you're going to get there.

That's the problem. Trip planning is interactive... that's why it's planning and not just informing the car. I need to know the remaining charge if I travel to my destination and then to a charging station. No way to get that info from the in car navigator. Well, not until I've reached my destination and then ask it where I can charge, if anywhere. It does seem to remember every friend's house where I've plugged into their 120 volt outlet. I guess that's a plus. lol

There's not that much to work out. It's a very simple formula to determine what happened to your rated miles. It is true that the car uses a lot of energy while parked, even if you aren't using Sentry/Summon Standby. That's not really an issue for range since when you care about range your car will not be sitting parked for any significant time, in general. (There are obviously important exceptions to this.)

Sorry, there can be tons to work out. I park at night with 15% expecting to make it to the Supercharger along my way the next day only to wake up with only 9% on the battery because the temperature dropped 20 degrees and now its raining, etc., etc., etc. At least now I can put 12% on my car while having lunch with a friend... if I don't mind walking the half mile from and to the chargers. Will summon work on public roads?