E90alex
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Search his username. It has been rehashed a dozen times in various posts.
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Charge to 100% - Do U Really Need To?
- Thread starter IvesSM
- Start date
I have read (and do read) research reports.
To date I have read more than hundred reports.
The research are so solid that there really is not any uncertainty about how lithium batteries behave.
I also bought two lots of Panasonic NCA cells and made my own tests, now concluded, which showed the same as the sum of the research.
And I applied it on my Model 3 P since new until I sold it after 2 1/2 years from new.
It had very low degradation compared to other M3P’s of the same age or less old.
Now I have a model S, that of course will be used in the same way.
This is a chart showing the calendar aging relative to time, state of charge (SOC) and temperature.
Relative capacity on the Y-axis is the capacity where ”1” = the new cell capacity.
This chart show us that low SOC is better than high SOC and that low temperature is better than high.
Calendar aging reduces with the square root of time (not shown here).
The clear step at 55-60% SOC is at about 57-58% for NCA cells, and comes from the ”central graphite peak”
Staying below that cut the calendar aging in half.
This chart is not the only one. There are a lot showing the same thing.
One common comment is that the research is not made on actual Tesla cells.
Heres Tesla Model S cells, taken out of a almost new car. They behave about the same. As we can see the cells age less at 100% than at 80%. This can be seen in many other research reports at medium and lower temperatures and I also saw this with my NCA cells.
Cells from the same cars was cycled in two different schemes, with higher load than we use when driving and when charging at home.
They where cycled 100-0% with 500 cycles, this is equivlent to 150K miles or so.
Relative capacity on the Y-axis is the capacity where ”1” = the new cell capacity.
This chart show us that low SOC is better than high SOC and that low temperature is better than high.
Calendar aging reduces with the square root of time (not shown here).
The clear step at 55-60% SOC is at about 57-58% for NCA cells, and comes from the ”central graphite peak”
Staying below that cut the calendar aging in half.
This chart is not the only one. There are a lot showing the same thing.
One common comment is that the research is not made on actual Tesla cells.
Heres Tesla Model S cells, taken out of a almost new car. They behave about the same. As we can see the cells age less at 100% than at 80%. This can be seen in many other research reports at medium and lower temperatures and I also saw this with my NCA cells.
Cells from the same cars was cycled in two different schemes, with higher load than we use when driving and when charging at home.
They where cycled 100-0% with 500 cycles, this is equivlent to 150K miles or so.
Hey Stew, what’s the code on SC for the 3 years free supercharging? I bought a 21 with free SC with code SC05, but I know there were no promos going on then, so I wonder if the free SC is limited time.
@SoManyM3s I don't know any code on SC that your referring to.
The 3 year free Supercharging is from the end-of-2nd-quarter sales promo on the S and the X.
The 3 year free Supercharging is from the end-of-2nd-quarter sales promo on the S and the X.
personally I set my charge to 60% and i plug it in every night. But for rare long trips i always charge to 100% and i lowerer the chargin ammps and i time it so that it finishes charging to 100% right before the time i'm about to leave. reason for this is to cut down the supercharger stops plus i pay 14 cents per kw/h at home vs close to 50 cents at super chargers. Plus its good to charge to 100% every once in a while go the battery gets a good full balance charge.
Would 55% on a daily basis be enough?
If @AAKEE 's graphs are correct, then at 60%, you are sitting right above the jump where the calendar degradation goes up by quite a bit. See the graph a few posts up.
The information here is useful, I wish there is a sticky thread for 'Best practices' on charging at home and supercharging.
On My 2016 Model S (75), I had been charging at 80% all along when I would likely have been OK with just 50%. But when I needed to make trips and did not want to trip to supercharge, I typically charge 100%.
My range when charged 100% had stayed at 232miles for the past couple of years.
Recently, I had to travel almost daily for couple of weeks (~130 miles) and so as not to hurt battery life, I started charging 90% instead of 100% but after the end of two weeks the range dropped by 10 miles! And based on the data provided by @AAKEE I think I made a mistake by charging to 90% for two weeks!(?).
I am picking up a MXLR this week and do not want to repeat the mistakes. Does this make sense?
1. Keep charged to 50% for daily commutes (rarely exceeds 40 miles/day)
2. For shorter round trips (100mi - 180mi) charge 80% or below to avoid supercharging (my FUSC will transfer, but I want to avoid stopping to charge)
3. For longer round trips (200m or more), charge 100% when leaving home.
4. If supercharging cannot be avoided, arrive at the supercharger with 10-20%
I also saw comments that said it is preferrable to leave as soon as 100% is reached (when charging at home), what is the rationale behind this?
PS: I get that convenience trumps everything else, at the same time if I can make the charging fit my convenience and not sacrifice on battery life, I would take it.
On My 2016 Model S (75), I had been charging at 80% all along when I would likely have been OK with just 50%. But when I needed to make trips and did not want to trip to supercharge, I typically charge 100%.
My range when charged 100% had stayed at 232miles for the past couple of years.
Recently, I had to travel almost daily for couple of weeks (~130 miles) and so as not to hurt battery life, I started charging 90% instead of 100% but after the end of two weeks the range dropped by 10 miles! And based on the data provided by @AAKEE I think I made a mistake by charging to 90% for two weeks!(?).
I am picking up a MXLR this week and do not want to repeat the mistakes. Does this make sense?
1. Keep charged to 50% for daily commutes (rarely exceeds 40 miles/day)
2. For shorter round trips (100mi - 180mi) charge 80% or below to avoid supercharging (my FUSC will transfer, but I want to avoid stopping to charge)
3. For longer round trips (200m or more), charge 100% when leaving home.
4. If supercharging cannot be avoided, arrive at the supercharger with 10-20%
I also saw comments that said it is preferrable to leave as soon as 100% is reached (when charging at home), what is the rationale behind this?
PS: I get that convenience trumps everything else, at the same time if I can make the charging fit my convenience and not sacrifice on battery life, I would take it.
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1. Pick a number. Personally I charge to 75%. It hardly ever happens, but I want to be covered for those unscheduled longer-ish local trips.
2. Makes sense
3. Also makes sense
4. You will find your new Model X charges crazy fast, regardless of the SoC upon arrival.
WRT 100% charge at home, the biggest thing I take in to consideration, is cost. Electricity becomes more expensive at 8 AM, so I want to be charged to 100% by then, regardless of what time I depart. The rationale is, you would like to minimize the time the car is sitting at 100%.
You will no longer have time for those longish lunch breaks while the car charges at a V3 charger.
No. If you need 90%, charge to 90%.
Its the time at SOC that cause calendar aging.
The loss of range was not a real degradation happening. Either the BMS was off before and the 90% helped the Bms to adjust (more likely), or the BMS got a bit off after charging to 90% (less likely).
Yes, and if possible charge late (next morning before the next drive) Not very important if you charge to 55% or less.
Yes.
No there is not. In normal temperatures 100% wear about the same as 80-90% or so.
Se below, no need to have panic about having the car at 100%.
In warm weather its slightly worse at 100% than 80%. Still no need to hurry.
In general, staying at 55% or below is good.
Minimizing the time above 60% is good.
Thats exactly what I recommend.
Don’t try so hard to reduce degradation that you get stressed or can not drive anywhere.
Its supposed to be fun
Joer293
MODEL X P100DL
I always do 100% before a long trip. Especially if I’m traveling rt95 through DC VA. Traffic and road construction can suck 30% of the battery over what trip planner shows. 100% also gets me to the grandparents house and back without supercharging. I get home under 5-10%, but worth it on the passenger Sanity. Oh, and unexpected rain/wet roads can really suck energy Too. At the beach, the HVAC couldn’t keep up while sitting in slow traffic with. 6 passengers, max blast, never got below 85F and humid inside the car. It was unusual for hvac to use so much energy, but seeing that 650wh/m keep climbing and the “charge now“ warnings only half way in a trip was nerve wracking. . That was the day the glass roof was not our friend. Drove the Acura and noticed how much cooler it could keep the car fully loaded. Rare case, but you asked about trip not daily driving. ah, there have been several trips where ”you can’t get there from here” backtracking because google maps were really bad. In the roadtrip instance, Nevada/Utah highways, wasn’t watching the energy gauge because Tesla’s don’t struggle And make engine straining noises. Road was flat, no vegetation for 100 miles. Just rock. When the car dinged to charge in the middle of nowhere, I realized it was over 1,000wh/m for the past 30 miles due to perfect 60-80mph headwinds. Autopilot kept it so straight didn’t notice. No trees to see the wind, no other cars either. I set autopilot to 35 -40mph I think to reach the next charger at 1-2%. I did think it really odd to see so many burn marks on the shoulder every couple miles from gas cars that had burnt up At some point. I learned why.
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