Older Teslas limited to 90kW Supercharging

[brianman]

We're about due for a "thread rebalancing", but until that happens I guess I'll ask here...

@qwk
"Rebalancing without charging to 100%"
Is there a technical reason why this is impossible or less effective? I guess what I'm asking is "Should we be asking Tesla for a 'rebalance my battery the best you can without increasing my degradation' button?" Speaking for myself, I don't mind if this button might take 12 hours to accomplish its task as I'd probably only do it 1-4 times a year.

 

[qwk]

We're about due for a "thread rebalancing", but until that happens I guess I'll ask here...

@qwk
"Rebalancing without charging to 100%"
Is there a technical reason why this is impossible or less effective? I guess what I'm asking is "Should we be asking Tesla for a 'rebalance my battery the best you can without increasing my degradation' button?" Speaking for myself, I don't mind if this button might take 12 hours to accomplish its task as I'd probably only do it 1-4 times a year.

I think that button is a range charge. It takes a very long time to balance your pack otherwise. Doing a 90% charge, letting it sit(about an hour), driving around the block, replugging, and repeating gets you a few rated miles of range back, but in my experience doesn't fully balance the pack.

 

[JRP3]

It probably has to do with how the BMS is programmed to handle balancing, and I'm guessing it's more aggressive near the end of charge.

 

[neroden]

How many times have you brought up the notion of suing Tesla on this forum?

I hope I never have cause to harbor such sentiment towards the people I do business with.

I hoped so too. Tesla made its bed and soon enough they'll sleep in it.

 

[bluetinc]

I didn't say anything about battery degradation, I said miles driven.

I'm not sure how this works then. We have an unlimited mileage warranty on the pack. What is the charge per mile driven?

I've been trying to follow this thread but may have missed a *few* details.

Is there any good data comparing degradation between 'A' and 'B' batteries?

No, it's still very anecdotal. Plug In America has added battery type to their info collected, so they would be the go-to place to be able to see any trends.

Doing it occasionally should have little long term effect, especially if it brings the pack into balance.

Yes, as long as you are not leaving the pack at 100% for long, your effect will be in the hundredths of a percent, but qwk a few pages back linked to a suggestion that a pack be left at 100% for months.

What are the highest and lowest voltage readings of each module(there are six readings per module)?

While doing what I suggested above is not that great for your battery, it's about the only quick way of balancing a Tesla pack. Just to clarify, there is nothing wrong with an out of balance pack, so balancing it for the sake of balancing is not that intelligent, but if someone must balance their pack, either that, or strictly 120V charging(and letting it finish and sit in 90% mode) over a period of several months are about your only options. The Roadster didn't really suffer from this pack unbalance, as the only charging modes that most people used were standard/range. Tesla didn't recommend the storage mode as a daily charging mode, because of this very reason. Some people did, and guess what? Their packs got out of balance, and Tesla recommended they charge in range mode and let the car sit.

Good, I'm glad we agree that it's not great for your battery pack. Mine were are all within 1/1000th of a volt of each other.

 

[qwk]

It probably has to do with how the BMS is programmed to handle balancing, and I'm guessing it's more aggressive near the end of charge.

Probably. The Model S BMS is very complicated, so comparing it to other BMS systems will only add confusion. That, and Tesla's inconsistent message, and you have a recipe for chaos.

 

[neroden]

Maybe I should move to Massachusetts.

Worth a try if it's practical for you. :wink: Probably not practical for most of us.

I can't get ANY diagnostic info out of them. While trying to verify a claim from the engineering department that they were "unable to reproduce" my 90 kW limitation I asked them to pull the logs from the supercharge session and compare them to the data I had provided. They said sorry, this info is proprietary and we can't disclose it. Ugh.

Absolutely typical behavior from Tesla Motors.

 

[qwk]

Good, I'm glad we agree that it's not great for your battery pack. Mine were are all within 1/1000th of a volt of each other.

So what were the voltage readings, if you don't mind me asking?

 

[neroden]

Dealer is defined as:

How interesting. Massachusetts does not define "dealer" the same way as New York (or indeed the other states I've looked at) does, so the MA Right to Repair Act doesn't apply to Tesla. I would never have guessed that. Thanks for the quote with the "pursuant to a franchise agreement" language.

Seems like that will have to be fixed in the next round of right-to-repair campaigning. In the meantime, it's time for someone who has enough money to start cracking Tesla's software, because it's become apparent that Tesla can't be relied on to do the right thing by buyers.

 

[qwk]

Yes, as long as you are not leaving the pack at 100% for long, your effect will be in the hundredths of a percent, but qwk a few pages back linked to a suggestion that a pack be left at 100% for months.

Please read post #28 in this thread. While nobody knows how detrimental it is to do this to your pack, it works.
Model s at 40,000 Miles - Page 3

 

[brianman]

I think that button is a range charge.

It is known that range charging can have a significant impact on your degradation. As such, it does not qualify for the button I've described.

- - - Updated - - -

Please read post #28 in this thread. While nobody knows how detrimental it is to do this to your pack, it works.
Model s at 40,000 Miles - Page 3

I'm having a Ghostbusters flashback. I'm waiting for the Stay-Puft marshmallow man to show up.

 

[bluetinc]

So what were the voltage readings, if you don't mind me asking?

Tesla seems to feel that this is proprietary, so while it was what I expected it to be, I'll leave it at that.

Peter

- - - Updated - - -

Please read post #28 in this thread. While nobody knows how detrimental it is to do this to your pack, it works.
Model s at 40,000 Miles - Page 3

I think there is some decent modeling for this, using voltage, temperature, time, a few cubes and such...

 

[qwk]

Tesla seems to feel that this is proprietary, so while it was what I expected it to be, I'll leave it at that.

Charging voltages are proprietary?

 

[smartypnz]

Charging voltages are proprietary?

I think that saying 'charging voltages are proprietary' is proprietary.

 

[DriverOne]

I'm just happy that Tesla included the SC hardware in my 60, even though I configured it without. That they built the hardware in anyway, and I could enable it, was a really great easter egg.

 

[brianman]

I would be remiss if I didn't report...

Last night I was able to get 92 kW charging on my Sig vehicle at Ellensburg. It was only for fractions of a second, when I toggled off climate control (that was running HI to reheat the cabin after a long, cold, climate-control-less journey) while supercharging at 89 kW. (It quickly corrected back down to 89 kW, sadly.)

 

[NigelM]

I would be remiss if I didn't report...

Last night I was able to get 92 kW charging on my Sig vehicle at Ellensburg. It was only for fractions of a second, when I toggled off climate control (that was running HI to reheat the cabin after a long, cold, climate-control-less journey) while supercharging at 89 kW. (It quickly corrected back down to 89 kW, sadly.)

Photos, or it didn't happen. ;-)

 

[wycolo]

> Mine were are all within 1/1000th of a volt of each other. [bluetinc]

How is that even possible, or not indicative of a measurement snafu?

> It quickly corrected back down to 89 kW, sadly. [brianman]

Mock sadness, I trust.
--

 

[smartypnz]

I would be remiss if I didn't report...

Last night I was able to get 92 kW charging on my Sig vehicle at Ellensburg. It was only for fractions of a second, when I toggled off climate control (that was running HI to reheat the cabin after a long, cold, climate-control-less journey) while supercharging at 89 kW. (It quickly corrected back down to 89 kW, sadly.)

Probably a good thing. To me this means that the charging is not reduced by other functions of the car. Probably still charging at 89 (or near 90), but drew more for the heating.

That would explain why we are seeing 120's doing 123 or 124.

 

[JRP3]

> Mine were are all within 1/1000th of a volt of each other. [bluetinc]

How is that even possible, or not indicative of a measurement snafu?

Why? Balanced cells should be sitting at the same voltage, or nearly so.