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What should my ideal charge percentage be?
- Thread starter Al Sherman
- Start date
Jim MacInnes
Member
At this same conference a GM engineer displayed some research that showed a 100 mile useful battery range provides for 90% of typical daily driving needs.
The problem with this is "What defines useful?"
100 miles on a not too hot and not too cold day is different than 100 miles in January in Toronto or July in Phoenix.
And you had better hope than no one goes on a weekend outing.
100 miles is basically a second car for commuting only, and typically the second car is the old primary car. Few purchase a new car as a secondary car. This kind of thinking is a recipe for failure.
BTW, what does this have to do with the thread topic
davidc18
Active Member
Picked up our 70D two weeks ago and the DS set the the charge limit to 90% so that is where I've left it.
Jim MacInnes
Member
The problem with this is "What defines useful?"
100 miles on a not too hot and not too cold day is different than 100 miles in January in Toronto or July in Phoenix.
And you had better hope than no one goes on a weekend outing.
100 miles is basically a second car for commuting only, and typically the second car is the old primary car. Few purchase a new car as a secondary car. This kind of thinking is a recipe for failure.
BTW, what does this have to do with the thread topic
For those of us who may want to try and minimize battery degradation, setting the charging level on the lower end of the 50% to 90% recommended charging range may make sense, when driving conditions permit. This is based on information posted earlier in this thread. Everyone will have their own personal definition of "useful" based on their driving habits, where they live, how far they travel each day, temperature conditions, elevation changes, wind speed/direction, etc. For me, 100 miles of "useful" range will meet most of my driving needs and it means being able to drive 100 miles with 40 miles of range to spare. This corresponds quite well with the GM data showing 100 miles of range will meet 90% of people's driving needs. And, 100 miles is 100 miles no matter where you live. If you need to bump your SOC in some cases to reach 100 miles that is easy. This is my primary vehicle and I also make trips in excess of 225 miles and adjust the SOC accordingly. I have dual chargers and we have 20 kw HPWC's at home and at work so with one or two hours notice I can easily top up the range, if needed. Everyone's situation is different. The beauty is the flexibility built into the Model S. Each of us can set it to up meet our own individual needs which may change from day to day. Its just a flip of a switch.
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I have a 2012 P85 - Vin 01586. When I first bought the car there were only two charge limits - 90%(Daily Charge) or 100%(Range Charge). I used to charge the car at 90% which gave the car roughly 245 miles of range and a rare 100% charge gave me about 265 miles of range. When I had about 14K miles on the car, Tesla changed the Daily Range charge via firmware which enabled us to charge the car in between the 90% range. So, I started charging the car in the middle of that range because I usually drive between 20 - 50 miles in a day. To my disappointment the 90% Daily Range of my car dropped down to about 213 miles and the Max Range to about 245. I then started charging the car every few days (instead of charging daily) to max Daily charge of 90% and slowly the range improved to about 226 for max Daily and about 248-250 on a rare max Range charge. However, lately I have noticed a message on the screen stating that charging the car to max Daily range may lead to degradation of the battery. So, now I am really confused. If I charge in between the Daily Range my range drops down but if I charge to 90% regularly the car says it is bad for the battery. By the way I live in San Rafael, CA a few miles north of SF. The summer weather here is mild with highs ranging from mid 70s to low 80sand the car now has about 32K miles.
So, I am curious about how other people are charging their cars. I have had differing opinions from Tesla SC employees. So, I will appreciate a feed back.
So, I am curious about how other people are charging their cars. I have had differing opinions from Tesla SC employees. So, I will appreciate a feed back.
Sosius
a.k.a. Uptown Frunk
Wow, this thread is dizzying. A lot of very smart people with a lot of data that is largely above my "finance guy" head. Since there is no definitive answer, I'm just going to use "daily" for daily, and "range" for when I want more range. Makes sense to me :wink:
If you charge to anywhere below 90%(the old daily charge), the battery will get out of balance, but will not degrade as fast. Getting the battery back into balance takes time, so if one needs the full range of the car very often(265 miles), then charging to 90% is the best bet.
I charge to 90% most of the time, unless it's 90+ degrees F, then I keep the car at 50%. My max range after 2.5 years and 37k miles is still 260+.
Unfortunately, in order to keep things simple, Tesla doesn't give much guidance on this. The basic things I do are:
1. Ignore rated range for any kind of degradation or balancing. The algorithm has changed many times. I used ideal range which appears to be more stable.
2. Charge to 80% unless I need a full range charge.
3. Set the timer so that the charging typically ends shortly before I start driving. In the summer this helps keep the battery at a lower SOC for most of the day and in the winter the battery is warmer when starting off.
No, I have never seen that warning(even in max range mode). What firmware version are you on?
Actually the original "daily" switch was 93 or 94%, not 90%. That's why daily charge used to be in the 240s. They lowered it to 90% to help prolong battery life. The error you are seeing now is because your slider is probably one tic higher at 91%. It's subtle and hard to notice but that'll cause the error to pop up because your in the max range mode boundaries.
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I haven't moved the slider in months. The slider has been at the indent between Daily & Max range for quite a while. This new warning started appearing recently. I'll try moving the slider slightly to the left and see what happens.
I had that warning appear on my screen a few months ago. I charged to 90% at one SC and then 45 minutes later, to 100% at another SC. And that warning about battery degradation appeared on my screen. I am not sure if it was based on the % I charged to, or just because I used 2 SC pretty close together.
I haven't seen the warning since, and charge my battery daily to 90% on a 14-50 outlet. I haven't had to use a SC since.
I figured the engineers at GM answered this question. We have a Chevy Volt with a 16 kw battery, but you can only ever use 10 kw of it, which is forced by the firmware. Chevy is backing the Volt's battery for 8 years and went for longest battery life over power and range. So I'll agree with the person who said, between 50-70% based on this.
I almost never charge at 100% and very rarely use the Superchargers. In the past year or so I used the Superchargers on a trip once to charge to about 98% and the other time to 90%. Otherwise I wait until the Rated range goes down to between 90-150 miles and then charge from my 14-50 outlet to the 90% indent on the charge screen - which gives me 225-226 miles. I can't understand why the car is giving me this warning the last few weeks when it didn't before because I am charging to the same level.
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