What's your 90%?

[Viking1]

Exactly - at 90% discharge & charge, you might get something like 5-600 cycles before you're into serious degradation (say 200mi x 500 cycles = 100,000 miles). Doing 5 times as many 20% discharges gets you something like 9000 cycles x 40 miles or 360,000 miles.

Nobody is going to drive like that every day, but you can see the effect of deep discharging and the benefit of smaller cycles and frequent charging.

Actually it is 80%, from 10% up to 90%, but I get your point. As I said, I was losing 1 rated mile/week during a period when I was using more supercharging. I think that is a lot. I've lost about 5% (14 rated miles (RM), based on 90%) after 9 months and 9k miles. I tried charging to 95% once to see if the RM would update. I was rewarded with another 1 RM drop.

Since I went to this frequent charging (using Tesla mobile connector, 10kW), using about 25%/day, given my daily commute, I've not lost any rated miles.

 

[Viking1]

My rated miles (RM) at 90%.

Mileage RM
6.............264
5,000......262
10,000....255

 

[Viking1]

You haven't damaged your battery. Lithium Ion cells degrade up to 5% within the first half year or year, and then slowly degrade thereafter.

Damage may have been too strong a word. However, I think I experience faster degradation of my battery then I would have otherwise experienced due to my Depth of Discharge (down to ~ 10%). Since stopping that I've not seen a decrease in my rated miles. Before stopping this I was losing 1 RM/week.

Note my RM history in the post above. it was been 5,000 and 10,000 miles that I experimented with discharge down to 10%.

 

[sdorn]

I've been lucky so far. I've had the car for 8 full months with just over 10,000 miles on the clock and have had absolutely no battery degradation whatsoever. Part of that is possibly because I charge it to 100% at least 2 or 3 times per month.

 

[Viking1]

I've been lucky so far. I've had the car for 8 full months with just over 10,000 miles on the clock and have had absolutely no battery degradation whatsoever. Part of that is possibly because I charge it to 100% at least 2 or 3 times per month.

How often do you charge? What is your depth of discharge on average? Did you ever get down to 10% or so?

I think you have a better BMS then mine. In my 90D then changed the chemistry, but it is the same number of batteries as the 85 and the same cooling system. I understand you have a better cooling system.

 

[sdorn]

How often do you charge? What is your depth of discharge on average? Did you ever get down to 10% or so?

I think you have a better BMS then mine. In my 90D then changed the chemistry, but it is the same number of batteries as the 85 and the same cooling system. I understand you have a better cooling system.

I charge every night to 90%. Most days I get down to about 70% or 75%. We take longer trips on the weekends and sometimes get down to 25% or so. It is pretty rare to get below that. I charge to 100% anytime we are going out of town just to make sure I have plenty of charge for whatever side trips or detours we might take.

 

[SmartElectric]

^^ exactly what we do, charge to 90% daily, 100% for longer trips and discharge to 20% (lowest was 7% a few times) only on trips. A plugged in Tesla is a happy Tesla.

 

[wdolson]

I've been lucky so far. I've had the car for 8 full months with just over 10,000 miles on the clock and have had absolutely no battery degradation whatsoever. Part of that is possibly because I charge it to 100% at least 2 or 3 times per month.

I think a lot of it is luck. I've had my S90D close to 15 months now and it has 0% degradation too. But I've only charged it to 100% once. I've gone to 95% a couple of times, but I have only done that once this year (by accident). My 100% is also 298 rated miles.

 

[Viking1]

I think a lot of it is luck. I've had my S90D close to 15 months now and it has 0% degradation too. But I've only charged it to 100% once. I've gone to 95% a couple of times, but I have only done that once this year (by accident). My 100% is also 298 rated miles.

What kind of depth of discharge do you average? I see from your earlier post that you have it plugged in at home.

I'm looking at a working theory that depth of discharge, rather than luck, can have a big effect on degradation.

 

[180r]

Sept 2015 90D 32.5K miles on original 19" tires => 244 RM @ 90% today here in NorCal.

40 amp nighly home charging to 63% unless range charging to 90% or 100% for monthly trips. I'm guessing 15% supercharging usage of total charging. 232 wh/m lifetime.

 

[wdolson]

What kind of depth of discharge do you average? I see from your earlier post that you have it plugged in at home.

I'm looking at a working theory that depth of discharge, rather than luck, can have a big effect on degradation.

My discharge cycles tend to be fairly shallow. I rarely go below 200 miles of range left, the average trip is about 40-50 miles. I've seen some people who discharge quite deeply who have low degradation, so I don't think it's the depth of discharge.

 

[MyJoule]

My non-AP car 36,500 miles- New it was 236 miles now 234 miles (sometimes 235 still) My wife's AP1 20,000 miles new 237 miles now 236 miles We charge every day to 90%, only 100% on road trips. rarely discharge below 50%- but have taken mine down to 17 miles once. Very happy so far- Temperature seems to be more of a factor than time- It's pretty hot here in our garage most of the year, high 80s low 90s. I think that has something to do with the range staying high

 

[SilverL]

Brand new 100D delivered @ 100% SOC - 336 miles.
90% is now 302 miles.

 

[soulreaver99]

Thanks for your post. I just got off the phone with the Service Center who stated that they reviewed my logs and that there were no hardware issues. They stated that my problems were due to a "firmware bug" and that I should charge to 90% daily (instead of 75%). I explained that I had ranged charged to 145 miles and received low charge warnings after 135mi of driving (~40kWh), which seems to me like reduced capacity of my 60 rather than a firmware bug. I'm supposed to now try a 90% charge on a daily basis to see if it fixes the "bug"...pretty disappointing.

Any update on how this worked out for you?

 

[asim120]

Any update on how this worked out for you?

The Service Center stated repeatedly that my battery was fine and that I did not need a battery replacement or repair.
I've been charging to 85-90% every morning, and my daily commute brings my SOC down to 65-70%. I've taken a couple of trips that have brought the SOC to around 20%. I plug my car in nightly.
Now, on the extremely rare occasions when I charge to 100%, I get around 160 rated miles. This has been my 100% for a few weeks.
I work with a lot of folks who are interested in purchasing a Tesla. I've recounted my situation and warned them of the lackadaisical support I received.

 

[blackscraper]

S90d, delivered at end of September 2015. 40k km on Odo. 90% RM 393km. Lifetime consumption 166wh/km.

 

[Viking1]

My discharge cycles tend to be fairly shallow. I rarely go below 200 miles of range left, the average trip is about 40-50 miles. I've seen some people who discharge quite deeply who have low degradation, so I don't think it's the depth of discharge.

All I know is that when I had a SOC range of 10% -> 90% I was losing 1 RM/week, charging once a week. Now after 2 months,, charging at every chance I get (almost daily), my SOC range is 60% -> 90%. In that 2 months time I have lost 0 RMs.

 

[SmartElectric]

All I know is that when I had a SOC range of 10% -> 90% I was losing 1 RM/week, charging once a week. Now after 2 months,, charging at every chance I get (almost daily), my SOC range is 60% -> 90%. In that 2 months time I have lost 0 RMs.

This may not be causal. Battery degradation is non-linear to start, and then flattens out.
In the past two years, we've not lost a single km of range in our early 2013 S85.

 

[Viking1]

This may not be causal. Battery degradation is non-linear to start, and then flattens out.

Perhaps. But one week I was losing 1 RM/week for several months charging 10%-90%. The next week I'm not losing any. It is like someone flipped a switch on my degradation. You can say may not be related but it is too much of a coincidence for me. Plus, the available research that was pointed to in other posts that Li-ion batteries have a larger number of recharge cycles when not doing deep discharges.

 

[EVgeek]

2016 85D. 17,700 miles. Range charge ~20 times. Lots of supercharging.

90% = 246 miles. 247 new.
100% = 272 miles. 273 new.