Do you have a source for that? Because all battery data I have seen does not do it that way, including that exact chart, which I have seen many times before.
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Is it okay to charge to 100% if I am immediately going to use it right away?
- Thread starter EVchiq
- Start date
I get that it feels more productive to charge to 100% before leaving a (SC) supercharger to go home, but what are your driving habits?
For example if you’re using up, say, 70% before you come back to your SC, it’s probably more efficient to charge up to 90 and come back at 20 than it is to charge up to 100 and come back at 30.
As I’ve noted before, this is a very misleading chart .. since it plots degradation against cycles instead of miles driven, resulting in a very distorted impression. Be CAREFUL when interfering this chart.
roblab
Active Member
Regardless of how many "DST events" you run, it's good to remember that the car will charge just fine on 110 volts. An extension cord is acceptable, and a car sitting outside using an extension cord from somewhere inside the house will charge the car enough for a day's use usually overnight. You don't need to drive off to a supercharger, even if it sounds like a quick fix, but if you do, remember that you have to sit and wait, usually alone, while the family enjoys "The Lone Ranger" without you. A 110-volt extension cord from your house or apartment will do the trick safely and completely while you sleep. Many here use them on occasion.
I also have built (Thanks to The Home Depot) several "extension cords" using #6 wire and the outlets and plugs necessary, and I keep them in my frunk. One is over 50' long, and I had one several cars ago that was 100' long. You never know when you'll need one. And contrary to all the "advice" on not using an extension cord, I've never had any type of trouble. I check for warmth at the plugs and outlets, but I have never felt anything more than mild warming.
I also have built (Thanks to The Home Depot) several "extension cords" using #6 wire and the outlets and plugs necessary, and I keep them in my frunk. One is over 50' long, and I had one several cars ago that was 100' long. You never know when you'll need one. And contrary to all the "advice" on not using an extension cord, I've never had any type of trouble. I check for warmth at the plugs and outlets, but I have never felt anything more than mild warming.
You don’t know their housing situation, so don’t make any assumptions about what they can or cannot safely do.
From the liability of someone else tripping on the cord to fines from the property owner or municipality, there’s so many limitations you may not be aware of.
ATPMSD
Active Member
The chart I presented is one of many ways to look at battery life and, as I said, this is a laboratory test and as far as I know Tesla batteries were not used. If is offered as a point of reference / information, so interpret it as you wish and use it or dismiss it as you see fit.
ATPMSD
Active Member
The chart is not bad, it presents what it intends to show. What you have done is create a new model that relates degration to miles. But your model can also be misleading based on the data used. Consider: 100,000 miles traveled in a car with a 400 mile range.
75-65% is just 10% * 400 miles = 40 miles per cycle which is then 2,500 cycle which plots to 96%
or
100-25% is 75% * 400 miles = 300 miles per cycle which is then 333 cycles, which plots to 94%
Now if I picked 75-65% insread of 100-25% then I would have gotten 96%!
Your model is probably better conceptually, but varies based on the SOC selected, whereas the original chart does not have this problem, so is your version bad? Of course not! They are simply different presentations, both valid and both have their limitations.
_Redshift_
Member
Regarding charging to 100%:
If you use it right away, it is fine. However it should not be too frequent.
Repeated supercharging also affects battery longevity. Temperature also affects the battery, it likes to remain at 72 F and at half state of charge which are ideal conditions.
If you use it right away, it is fine. However it should not be too frequent.
Repeated supercharging also affects battery longevity. Temperature also affects the battery, it likes to remain at 72 F and at half state of charge which are ideal conditions.
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Charging to 100 is perfectly fine as long as you’re not doing it everyday. Don’t let the range anxiety get to you about having that extra battery percentage. Most of the time you don’t need the car above 70-80% in my experience don’t worry about getting home with low battery. Have fun with the car don’t stress.
Sorry to necro this thread, but I too would like to get a source for that graph so that we can verify how a “DST Cycle” is defined.
If, as @ATPMSD posits, a single “DST Cycle” is defined as one discharge/charge event and does not account for the depth of discharge in any way (in which case discharging from 75% to 65% OR from 100% to 25% are both counted as a single DST Cycle), then the chart actually shows the opposite of what it appears to show: that deeper discharges are better for real-world battery longevity.
The 100%-25% scenario shows degradation ~3x greater than the 75%-65% scenario per DST Cycle. But you’re extracting roughly 7.5x more energy per discharge in the 100%-25% case. So once you factor in the depth of discharge, the 75%-65% scenario would actually be degrading ~2.5x faster than the 100%-25% scenario when assessed on a per-kWh or per-mile-driven basis.
This seems implausible to me (based on everything I’ve read about battery health over the years), which is why I also question the assertion that a “DST Cycle” on this graph doesn’t correct for depth of discharge.
davewill
Active Member
I see little point to charging to 100% unless you anticipate needing it. Also, doing so at a public charger can unnecessarily make others wait to charge.
I charge to 100% whenever I need to drive more than 100 miles. My schedule normally requires driving over 100 miles 1-2 times a week. I do this:
1. Charge my car to 85% as usual the night before.
2. Before I sleep I turn on the scheduled charging and set it to start charging at 6:30am.
3. I change the charge percent to 100%.
4. By morning (8am) it's at 325 miles.
1. Charge my car to 85% as usual the night before.
2. Before I sleep I turn on the scheduled charging and set it to start charging at 6:30am.
3. I change the charge percent to 100%.
4. By morning (8am) it's at 325 miles.
Completely unnecessary to charge to 100% for 100 miles of travel. I only charge to 100% if I would otherwise be predicted to arrive back home with less than 15-20%.
ucmndd
Well-Known Member
This is the source, near as I can tell.
I feel it is necessaary since it's a long distance. One route I take the speed limit is 70mph. I drive 80mph and easily use up "150 miles" on the battery. Charging to 100% when using it well past 85% is perfectly fine. I even asked the service center twice (two different techs) and they both stated it was a nonissue. The only problem is if the car is KEPT at 100% for a long period of time.
Also, for you being at 15-20% may be fine. But, not everyone has the same driving habits as you. I own and manage properties that are as far out as 1.5 hours drive. Not going to allow my battery to be low "just because". That's foolish. I need my car to drive a good distance at any moment.
Allowing your battery to be down to 15-20% is the same as people who don't fill their gas tank until "E" - LOL.
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The service centers (and Tesla itself) don't give a damn about minimizing your battery degradation. They just care that it doesn't degrade so much that they have to pay for a replacement under warranty (and even if they do, they do not guarantee that you'll get a new one, only one that has less degradation than the warranty guarantees).
The effect is cumulative. Keeping the battery at a higher SoC than it needs to be accelerates calendar aging. Keeping it high just because you might need to drive "a good distance" on a moment's notice does more harm than good, especially if these moments occur only a few times a year. It's probably better to supercharge in the rare case that does happen if it only happens once every few months.
There's no harm in going all the way below 10%. And if you need just a little bit more to get back home, it's probably about 3-5 minutes on a supercharger once you get below 20% SoC.
No, it's not the same, although there are benefits to running the tank all the way down to empty (reducing the overhead of burning fuel to get fuel). Plus, have you ever flown a plane? You never put more fuel in than what's required to get to your destination, plus a small reserve, because it takes fuel to carry fuel. But in this case, it's like keeping your tank more full than it has to be literally causes your tank to get smaller, and the more full the tank, the faster it shrinks. If I had a gas pump in my garage and the tank constantly shrinks in proportion to how much fuel is in it, then I'd only ever put in just enough fuel to get to my destination and back, plus a reserve, just like you do in a plane. You certainly don't ever put in a 40% reserve; that's ridiculous (unless you are flying to IPC (Mataveri International Airport on Easter Island), the world's most isolated airport, where an incident that closes the runway means you have to go all the way back to your origin at SCL). Even at 80 mph, you'll get 250-270 miles of real world range out of 325 indicated miles. I'm not sure exactly how far you are driving but you said you need to go "more than" 100 miles. Except you're charging up enough to go "more than" 250 miles, which is ridiculous. Even if you had to drive 150 (real world) miles in a day @ 80 mph, you'd easily make it back with about 10-15% left if you charged to 70%.
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