Decreasing rated range.

[Dave EV]

do we know if it's limited on the lower side or the upper side? In other words, does the car only charge from 0% to max 66% and stop, or can you only discharge from 100% to 33% and it stops?

Unless someone can get access to pack voltages, or Tesla tells someone, no.

In either case, given lithium ion chemistry, it's practically impossible to ever balance this pack and accurately calculate charge capacity. If you can't charge to 100%, you can't balance the pack, the cells will become very imbalanced, and you can't ever accurately calculate degradation. If you can't charge below 33%, then just the same you won't ever be able to accurately know remaining SOC. (I might be getting my terminology mixed up here, SOC, charge capacity, etc).

Yeah, but it doesn't really matter that the pack isn't balanced all that well.

UNLESS they cycle the battery packs. (I think think this would be the ideal implementation).

That would be a crazy and expensive way of doing it. Much easier to simply cycle the pack somewhere in the middle by altering the cutoff voltages.

I don't think this is true. When doing a full charge to 100% the management should be able to tell that no more power is being taken by the batteries and heat is building up instead, at least that is what seems to happen in other systems

Lithium batteries don't generate any significant heat if charged properly unless you are abusing them. That's why the charge rate tapers down as the pack reaches 100% SOC.

 

[AmpedRealtor]

I hate to add more complexity to this, but if anyone is really comparing, the mileage on the car is not adequate as a data point. You need to also use the average Wh/mi in order to measure degradation. The Panasonic charts relate to number of charging cycles. If possible, we should look at (odometer * (Wh per Mile / 1000)) to get kW used. These is a big difference in Wh/mi depending on driving style and where you live. Easily up to 100 Wh/mi average difference at the extreme. I baby my car in a warm climate and my lifetime average is around 317. I'm being a bit conservative with that number because I can't tell you exactly, because Tesla keeps resetting my trip computer.

Arizona here, lifetime usage is 293 Wh/m and dropping. Recent 100+ mile errand trips were done using 270 Wh/m or less. That's just how I drive.

 

[darthvdr]

At 8000 miles now and on a standard charge, we are at 232. Have not tried 100% yet.

 

[gg_got_a_tesla]

Arizona here, lifetime usage is 293 Wh/m and dropping. Recent 100+ mile errand trips were done using 270 Wh/m or less. That's just how I drive.

Wait till your summer hits and you are forced to use the AC indiscriminately!

 

[Benjamin Brooks]

Arizona here, lifetime usage is 293 Wh/m and dropping. Recent 100+ mile errand trips were done using 270 Wh/m or less. That's just how I drive.

OK, so what is your 90% charge rated miles remaining come to then?

 

[markb]

I posted earlier thanking those who responded to my query regarding my very significant loss of range on my 40, but I got a msg stating that it needed to be approved by a moderator and I'm not sure it will ever show up.

As others have said, I'm pretty sure the battery is never fully charged, maxing out at 72% of capacity. The slider lets me set any charge between 0 and 72.

My car as delivered charged to 140 rated and 160 ideal, as promised. I am now down to 118/136 after 9000 miles - far from what we were expecting.

Two weeks ago, my service mgr told me there would be firmware update in 2-3 weeks that would restore some of the lost rang. We'll see.

 

[Gear]

I posted earlier thanking those who responded to my query regarding my very significant loss of range on my 40, but I got a msg stating that it needed to be approved by a moderator and I'm not sure it will ever show up.

As others have said, I'm pretty sure the battery is never fully charged, maxing out at 72% of capacity. The slider lets me set any charge between 0 and 72.

My car as delivered charged to 140 rated and 160 ideal, as promised. I am now down to 118/136 after 9000 miles - far from what we were expecting.

Two weeks ago, my service mgr told me there would be firmware update in 2-3 weeks that would restore some of the lost rang. We'll see.

Out of curiosity, what's your normal charge routine like? What's your typical daily charge? How often do you charge to the "full" 72%?

 

[markb]

@gear, ALways charge to 72%, every night, generally drive between 30 and 50 miles daily. Weekends sometimes more, rarely more than 80 miles a day, sometimes less. Until the cold winter hit in NY, I had a lifetime average of approx 290 wh/mile. Now we have a lifetime avg of approx 315.

 

[SFOTurtle]

Yeah, but it doesn't really matter that the pack isn't balanced all that well.

What is your source for this? From a technical level, I don't know and am not aware of anything Tesla has told us about whether a pack that is severely out of balance can cause harm in the short or long term.

From a practical standpoint, it does matter when we're talking 10-15 rated miles difference between what the car is telling us we have and what we might or might not have in terms of actual energy in the battery. If I need to take a 160 mile trip, and instead of my car showing 205 rated miles and having a lot of buffer, it shows 190 rated miles at full charge and having no or negative buffer (unless I drive 55 mph on the highway), then the car is forcing me to schedule a charging stop somewhere that I otherwise would not have to do if the battery was better balanced.

 

[Dave EV]

What is your source for this? From a technical level, I don't know and am not aware of anything Tesla has told us about whether a pack that is severely out of balance can cause harm in the short or long term.

My statement was in reference to "40 kWh" cars where capacity is artificially limited (assuming that the proper logic is used when calculating SOC!).

If the SOC slider is limited to 72% it seems pretty clear that they Tesla is simply limiting the maximum charge voltage to limit the cars to ~40 kWh.

If markb's 40 kWh car is only getting 118 rated miles down from 140 rated miles, it's pretty clear that Tesla's balancing and SOC measurement has some bugs in it that are improperly causing the appearance of capacity loss. One possible cause is that they use the module with the highest voltage as the SOC and if there is a module out of balance with a higher voltage than the rest, it's stopping the charge prematurely. And then perhaps Tesla does not balance the pack much at 72% SOC much.

Simple solution for the 40 kWh cars would be to use the lowest module voltage to determine SOC and when to stop charging.

 

[NigelM]

I posted earlier thanking those who responded to my query regarding my very significant loss of range on my 40, but I got a msg stating that it needed to be approved by a moderator and I'm not sure it will ever show up.

As a new member some of your posts were going automatically into moderation, that's just our proven strategy for preventing spam but sorry if we didn't get to them faster. I approved all of yours that were still queued and you should be good to go now.

A belated welcome to TMC!

 

[SCW-Greg]

I assume you mean 60-65 miles per day during the week? That makes the math for your total mileage work out about right. If so, that's about my commute as well. Another night or two during the week I add an extra 25 miles or so.

On weekends it varies from only 20 miles total, to a couple of hundred. When you say "another 15", is that total for the weekend... or 65+15=80 for each day?

Yes, good catch. 60-65 per day during the week. And about 15-20 over the weekend.

We've only range charged (100%) 4 or 5 times.
Last weekend being one of them. We did a 600 mile trek to family in Seattle, and then up to Bellingham and back, hitting two SCs along the way, and then each again on the way back.

 

[NigelM]

Mod Note: some posts went here - Kman-s-Battery-Care-amp-Maintenance-Merge-Duplicate

@All members: please don't post the same item in multiple threads.

 

[Veronika]

I have a 40 that thinks it is a 60. When I got it last May max charge got me 143 miles......now max charge only gives me about 130...sometimes then even reduces to 125.....I thought that if you leave it plugged in now it will use energy from the ground connection versus battery. Also why am I getting so many less miles in general? 10 may be nothing for the 60 and 85s out there, but I covet every mile!! ; )

New to TMC!! thanks
Veronika

- - - Updated - - -

I meant a 60 that thinks it is a 40.

 

[markb]

I have a 40 that thinks it is a 60. When I got it last May max charge got me 143 miles......now max charge only gives me about 130...sometimes then even reduces to 125.....I thought that if you leave it plugged in now it will use energy from the ground connection versus battery. Also why am I getting so many less miles in general? 10 may be nothing for the 60 and 85s out there, but I covet every mile!! ; )

New to TMC!! thanks
Veronika

- - - Updated - - -

I meant a 60 that thinks it is a 40.

Veronika, watch the video referenced in the above thread. It will explain decreasing range, but won't make you happy.

- - - Updated - - -

Mod Note: some posts went here - Kman-s-Battery-Care-amp-Maintenance-Merge-Duplicate

@All members: please don't post the same item in multiple threads.

Veronica, I mean this one.

 

[bluetinc]

Hi Veronika,


Nice to see you on TMC. The issue that most people think is being seen on the 60's that that they never get to run through a full balance cycle as they should, and would, if set to the "60" mode. I don't think anyone has been able to prove this. A great way to verify this (and if true, get your mileage back), would be to have service (while in their care only I'm sure) set your car back to being a 60, and preform a full charge and balance, and then set it back to a 40 for you.

Has anyone with a 40 asked service to do this?

Peter

I have a 40 that thinks it is a 60. When I got it last May max charge got me 143 miles......now max charge only gives me about 130...sometimes then even reduces to 125.....I thought that if you leave it plugged in now it will use energy from the ground connection versus battery. Also why am I getting so many less miles in general? 10 may be nothing for the 60 and 85s out there, but I covet every mile!! ; )

New to TMC!! thanks
Veronika

- - - Updated - - -

I meant a 60 that thinks it is a 40.

 

[Veronika]

I thank you before watching the video and my ensuing depression! ; )

 

[Sacrament055]

I posted earlier thanking those who responded to my query regarding my very significant loss of range on my 40, but I got a msg stating that it needed to be approved by a moderator and I'm not sure it will ever show up.

As others have said, I'm pretty sure the battery is never fully charged, maxing out at 72% of capacity. The slider lets me set any charge between 0 and 72.

My car as delivered charged to 140 rated and 160 ideal, as promised. I am now down to 118/136 after 9000 miles - far from what we were expecting.

Two weeks ago, my service mgr told me there would be firmware update in 2-3 weeks that would restore some of the lost rang. We'll see.

I have a 40 as well and had a lifetime average of 270 Wh/m prior to the cold. Now I'm up to 296 wh/m and I'm finding that my range will fully charge and say I have 129 on a warmer day and 120 ish on a colder day but if the battery pack isn't nice and warm when I'm leaving the house I'd be lucky to get 100 to 110 miles on that charge. When I have the pack heating and the heat on in the car I see the wh/m jump up to max at times. I've tried setting the range mode option and it does keep the spike down but it also means the battery pack takes significantly longer to heat if it's even warm by the time I get to work 20ish miles each way.

That is a bit disappointing since as stated by others my 40 started out at full charge of 145 rated miles and I used to be able to get even better mileage than that. Pretty significant drop to lose roughly a third of my range in the extreme cold.

 

[islandbayy]

Hi Veronika,


Nice to see you on TMC. The issue that most people think is being seen on the 60's that that they never get to run through a full balance cycle as they should, and would, if set to the "60" mode. I don't think anyone has been able to prove this. A great way to verify this (and if true, get your mileage back), would be to have service (while in their care only I'm sure) set your car back to being a 60, and preform a full charge and balance, and then set it back to a 40 for you.

Has anyone with a 40 asked service to do this?

Peter

That is a VERY good idea!!!!

 

[markb]

Hi Veronika,


Nice to see you on TMC. The issue that most people think is being seen on the 60's that that they never get to run through a full balance cycle as they should, and would, if set to the "60" mode. I don't think anyone has been able to prove this. A great way to verify this (and if true, get your mileage back), would be to have service (while in their care only I'm sure) set your car back to being a 60, and preform a full charge and balance, and then set it back to a 40 for you.

Has anyone with a 40 asked service to do this?

Peter

Peter, I know I haven't, and I have not heard of any 40 that has. Tesla has not yet admitted to anybody, as far as I know, that the range loss experienced by 40's is anything other than normal.

I agree tha it would be interesting to have them unlock a 40, charge to 100% and see what happens. Not sure why they would have to do it at a service centre, though. Unless they take a 60 mile joy ride afterwards, we'd still be getting a "free" 60 miles.

What might be nice, on a long term basis, is if they unlocked our car maybe once a month and allowed us to do one 100% charge. But again, first they have to admit there is a problem and that 100% charging would solve it.