S85 Battery Degradation

[Dhnelson26]

I know this thread has been done before, but I am looking for some fresh data. For the S85 folks out there, whats your milage, and whats your 90% rated miles. I am at 101,000 miles and my 90% is 203 rated miles... That seems too low, but I want some more data points. I still love the car!! Appreciate the help! Cheers!!

 

[Dhnelson26]

I have a 2013 P85+ with 88K miles. Battery when full: 245miles Battery at max daily: 223miles
Love my car. No maintenance whatsoever. Just changed the 12V battery recently and the air bags recall done by Tesla at home. Cost: $0.00. In 4.5 years my only expense has been tires at about $0,09 per mile (Michelin sport 2 ,low profile)

 

[Model S P]

I have a March 2013 P85 with original "A" battery and 39k miles. My 90% is 224 and 100% is 252 rated miles. I keep it charged to 60 to 80% nearly all the time except on trips. I estimate about half of the 39k miles are trips with supercharging. Supercharging has become noticeably slower. Yes, I'm aware of front louver failures and the other factors that affect SC speed.

 

[David99]

I have a March 2013 P85 with original "A" battery and 39k miles. My 90% is 224 and 100% is 252 rated miles. I keep it charged to 60 to 80% nearly all the time except on trips. I estimate about half of the 39k miles are trips with supercharging. Supercharging has become noticeably slower. Yes, I'm aware of front louver failures and the other factors that affect SC speed.

Thanks for the info! Interesting for me o hear that you also noticed a slowdown in Supercharging despite having far less miles than I have. I always thought that the slowdown is due to battery aging but it seems that Tesla has decided that the charge rate needs to be reduced for this battery pack regardless of age.

 

[RyanT]

90%: 234 rated miles
almost 100% (still charging): 261+

Dec 2014 build - 54K miles

Mine is about the same. Dec 2014 P85 with over 70k miles. 90% is 232 and 100% is a 259. Lots of supercharging on it ~150 sessions.

 

[Raven]

To the OP, I'd suggest doing a full cycle or two on the battery to see what it does. I've heard of some saying the battery can sometimes "learn" a certain battery level and/or it's just unaware of how much is truly available. Charge to 100, then down to 10 or so and back. Report back with new 90% if there is a new number.

For reference, my 02/2013 S85 with 56,000 miles was 221 miles at 90%

 

[Lanber]

Just a bit of caution if you cycle the battery. When you go deep deep low on SOC keep a very keen lookout on powerlimit and know that it will shutdown at 20kw limit, wouldnt recommend going below 40kw limit. Already there you should be 2kwh below 0km if the algorithm is correct. On my car it was spot on, changed by 0.1 kwh after a complete sycle.

And/or have a OBD plug connected so you see what the car is thinking.

Also. Below 5% SOC indicated the car will stop charging the 12V battery. So that may cause you to get stranded if it`s weak and you take a long time to drain main battery while lights / heating fan are running.

 

[taminatorv]

I've got a September build 2013 S85 with 63k miles on it. Over the last year, rated range has dropped from 208 miles at 80% to 193 miles. I charge to 80% every day except for four road trips a year where I charge to 90-100%. I tried a 100% charge yesterday and only got 241 miles, down from 254 last year. As it got closer to 100%, it estimated 5 minutes remaining for half an hour. Do I need to do more 100% charges to balance the pack?

 

[David99]

I've got a September build 2013 S85 with 63k miles on it. Over the last year, rated range has dropped from 208 miles at 80% to 193 miles. I charge to 80% every day except for four road trips a year where I charge to 90-100%. I tried a 100% charge yesterday and only got 241 miles, down from 254 last year. As it got closer to 100%, it estimated 5 minutes remaining for half an hour. Do I need to do more 100% charges to balance the pack?

No, balancing happens at any charge level.

 

[MP3Mike]

No, balancing happens at any charge level.

We have it on good authority, @wk057, that balancing doesn't start until you charge above ~93%.

 

[Brass Guy]

I've got a September build 2013 S85 with 63k miles on it. Over the last year, rated range has dropped from 208 miles at 80% to 193 miles. I charge to 80% every day except for four road trips a year where I charge to 90-100%. I tried a 100% charge yesterday and only got 241 miles, down from 254 last year. As it got closer to 100%, it estimated 5 minutes remaining for half an hour. Do I need to do more 100% charges to balance the pack?

My car is maybe a month older than yours, but closer to 2x your miles.
That drop doesn't sound like enough to be a bad module, especially if it was gradual over a year. It is worse than mine at 80% (196-197). Mine has been very stable for a long time now. Speculation is that with narrow cycles, the range estimate can get a little off each time, so there's one possibility.
Mine also takes seemingly forever to get that last bit to 100%, and I don't think the last 1/2 hour adds even 1 mile. I haven't finished a 100% charge since last year, when it hit 247. (Up from 245 the previous complete 100%).
You could bring it to Tesla, they'll check it out. And probably tell you it is within performance specifications, but if they find a bad module you're covered.

 

[David99]

We have it on good authority, @wk057, that balancing doesn't start until you charge above ~93%.

It is triggered at 93%, but balancing itself happens at any state of charge. We also don't know if Tesla has other ways of measuring balancing at other levels or other methods. Finding one thing doesn't mean there is nothing else going on.

I have two years of watching my cell balancing on the CAN bus and even after extensive periods of time without ever charging to 93% or higher my pack never got out of balance more than 0.2%. That's good evidence that a pack does not get out of balance when partially charged for a while. It makes sense considering that Tesla recommends to only charge up to 90% (or less) on a daily bases. If balancing would only be measured and triggered at 93% or up, the battery pack would never be triggered in the most used and recommended case. I highly doubt that Tesla would design it that way. The difference in voltages between cells is actually greater at low state of charge, yet another good reason to have the BMS look at that for balancing.

But the main reason I replied at all is that for some odd reason this myth keeps coming up that lost range is due to cell imbalance and you need to charge to 100% to balance it. That's not the case in Tesal's BMW.

 

[taminatorv]

If it's just the range estimate from the narrow cycles, I should just put it back to the battery percentage display and forget about it.

 

[David99]

If it's just the range estimate from the narrow cycles, I should just put it back to the battery percentage display and forget about it.

That's actually what Tesla said in an email. Shallow cycles on the battery can make the range estimate become less accurate. Doing a (near) full cycle can re-calibrate the algorithm and make it more accurate again. So doing a 100% charge and going down to a few % every once in a while can be helpful.

 

[efusco]

2012 S85 94,000 223 miles (originally 242) at 90% (8% loss), 247 (originally 272) at 100% (9% loss)

 

[Lanber]

Got a massive imbalance 16 may. 3.9v MAX and 3.5v MIN. Car shut down 20km later. Think something went very wrong.
Car was parked for 1.5 days at 80% SOC in hot weather (hot for Norway anyways, 25C). When starting it showed 170km range remaining and 65% SOC. Right now it says 240km on APP, still have contact with it.

Fingers crossed for a 90kwh pack

 

[efusco]

Got a massive imbalance 16 may. 3.9v MAX and 3.5v MIN.

What does that mean? Where did you get those numbers? I'm not sure what you're talking about here.

 

[David99]

What does that mean? Where did you get those numbers? I'm not sure what you're talking about here.

The battery pack is made out of ~7000 individual cells. It is important that all these cells have the same voltage (or as close as possible). Due to various reasons the cells sometimes drift apart. The BMS can even them out and does so all the time. A difference of 0.2% is fine, a 1% difference would be not so good, a 10% difference, as mentioned above, is when something serious is going on.

Tesla does not show the owner any of that info. You can to look at the CAN bus. I have been doing that for 2 years and watched how much the cells drift apart. It is really minimal. I typically see only 0.1%

 

[CarolinaBMXers]

236 @90%....15’ with 68k

 

[supratachophobia]

I know this thread has been done before, but I am looking for some fresh data. For the S85 folks out there, whats your milage, and whats your 90% rated miles. I am at 101,000 miles and my 90% is 203 rated miles... That seems too low, but I want some more data points. I still love the car!! Appreciate the help! Cheers!!

Do you have access to CANbus data?