Yes Tesla service mode has recommendation for max battery SoC when transporting/storing batteries. Certainly less than 48% and lower if transporting by airplane
I wish Tesla would reduce minimum charge limit from 50% to 40%
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What Percent is Your Tesla Charged to While at Home?
- Thread starter Resist
- Start date
I wish Tesla would reduce minimum charge limit from 50% to 40%
Max Spaghetti
Member
Ok, just to be a pedant
I agree with all the other points but I haven't seen any research claiming any benefit to small DoD - I'm not saying it isn't a thing, I just haven't seen it. In practice, a large DoD inherently involves charging to a large SoC every time, of course, so maybe difficult to prove in isolation.
However, are you implying that if, for example, we only ever charge to 50%, that it is better for the battery to drain to 40% and recharge 4 times in succession, rather than draining to 10% and recharging once?
E90alex
Active Member
Yes, it’s better to charge daily even if you just used a few % rather than wait until it gets low before recharging.
The data floating around here somewhere if you search for it.
The data floating around here somewhere if you search for it.
The paper I linked to in #458 has a section and Graph on that.
I don't think you can make that conclusion from the paper in #458. They only tested 10% cycle ranges, they didn't compare them to larger cycle ranges. If anything, I would conclude from that paper that 10-20% > 10-50% > 40-50%. The reason I would place 10-50% over 40-50% is because the average cycling SoC would be lower in the 10-50% than 40-50%, and there is a correlation between SoC and degradation in that paper.
It’s 30% cheaper to charge at the 72kw supercharger a few min from where I live (thanks PGE) so I try and charge as little as possible at home.
aerodyne
2 of 3 EV's - Defect Free!
Hmm I suggest reading it again... (I agree it's not the best article as there are too many variables. However it is at least interesting for what it's worth.)
If your case with an LFP battery car, DoD doesn't really matter for LFP degradation. In fact a shallow DoD could have some negative effects on LFP in the form of reversible degradation due to lithium sequestration. Almost all forms of charging-related degradation doesn't really apply to LFP batteries, including supercharging.Ok, just to be a pedant
I agree with all the other points but I haven't seen any research claiming any benefit to small DoD - I'm not saying it isn't a thing, I just haven't seen it. In practice, a large DoD inherently involves charging to a large SoC every time, of course, so maybe difficult to prove in isolation.
However, are you implying that if, for example, we only ever charge to 50%, that it is better for the battery to drain to 40% and recharge 4 times in succession, rather than draining to 10% and recharging once?
Shallow DoD and avoiding supercharging are important for high nickel-based lithium packs.
After 16 months and 25000 miles later my battery has degraded from 346 miles to 333 miles.
johnnycnote
Member
Stew-2
Member
2022 M3P, 24 months old, 23k miles and I’m down to 307 from 315 when new.
Daily charge to 53% for commuting and to 60-75% occasionally when I need to drive further.
Daily charge to 53% for commuting and to 60-75% occasionally when I need to drive further.
Your battery has ~ 74.6 kWh capacity.
I guess you charge to 70-90% mostly?
@Stew-2 you’re at 78.4 kWh. Very good, the low SOC saves the battery.
These to batteries are the same version with the same capacity.
Yes. The low SOC really does work if you do it consistently.
I'm still at 344 (of 358) extrapolated miles at full charge with no apparent decline in last 7 months or so. Coming upon 20 months.
I'd like to thank you---it was your thread here (and the key research paper on calendar aging) that pushed me to adopt a strategy that I saw recommended literally nowhere else, despite significant searches. I did this (daily charge limit < 55%) from the first day I owned the car. The science works, and is correct. The key points are understanding that calendar aging matters much more for ordinary drivers even though 98% of the public and science focus is on cyclic aging, and then understanding the shelf-nature of calendar aging rate vs SOC.
I had to maintain faith in peer reviewed research through some uncomfortable BMS recalibrations where it looked like the degradation was faster and like everyone else's (who charges to 80-90%). But eventually it recalibrated again and the success of low SOC strategy proved true.
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Good!
In the first year of my first Tesla, the M3P ’21 I couldnt swear that it was just because of this but I could see that it actually did follow my calculation done before I got it.
(For a short while I thought it even did better, until i adjusted the average cell temp down, then it was spot on).
My Plaid is at 97.4-97.5 kWh (still full range), after ~10 months from build date, which again is precisely spot on.
Steve446
Dusty Crophopper, M3 LR 2021 Midnight Silver
Agreed, as you and Dr Chaos mention, I have that feeling too.
Look at the database in the @eivissa battery survey:
[Survey] Battery Degradation - All models from 2019
This is an attempt of a deeper dive into the battery degradation of all the different battery packs. In order to take part the preferred way is to fill out this Google form: https://forms.gle/RUSRrpmCaUx3XbWr7 If you have already gathered these values and want to batch copy paste, then within...
teslamotorsclub.com
The graph, Daily SoC Limit v Calendar Degradation shows some variable results however.
The question I would like to pose here though is one regards the kinetics of the degradation process itself and your comments above.
I realize that the kinetics of this process can likely be impacted by a number of parameters - as you frequently point out to some forum participants!
Equally, I assume that we are observing a macro effect ie an aggregate view of the different, individual cells and their specific status regards SOH/capacity.
So, assuming that this is just a physical-chemical process, can we assume that reduction in capacity is a continuous activity or, an activity that occurs in discrete amounts or packets from time to time? I wager for a continuous activity based on my seat of the pants understanding of all this.
In this context, it's interesting to look at the database table and the tabs, "degradation per month" and, "degradation per cycle". I admit I hadn't thought of these as measurable parameters until I saw the database (thank you @eivissa !). As one can imagine the effect is quite small, observable for calendar aging but much less for per cycle. For me the per cycle seems to be within the error of the measurement/calculation so difficult to interpret. The calendar per month though seems quite meaningful and of course different for different batteries. Nevertheless interesting.
The underlying degradation from calendar aging appears to be slow and continuous. It is side chemical reactions. Even rare chemical reactions happen with some rate if you give anything enough time. (If there is a sudden change that's probably a dendrite happening and the cell is about to fail catastrophically---not good.)Agreed, as you and Dr Chaos mention, I have that feeling too.
Look at the database in the @eivissa battery survey:
You are already familiar with that as I recall.
[Survey] Battery Degradation - All models from 2019
This is an attempt of a deeper dive into the battery degradation of all the different battery packs. In order to take part the preferred way is to fill out this Google form: https://forms.gle/RUSRrpmCaUx3XbWr7 If you have already gathered these values and want to batch copy paste, then within...
The graph, Daily SoC Limit v Calendar Degradation shows some variable results however.
The question I would like to pose here though is one regards the kinetics of the degradation process itself and your comments above.
I realize that the kinetics of this process can likely be impacted by a number of parameters - as you frequently point out to some forum participants!
Equally, I assume that we are observing a macro effect ie an aggregate view of the different, individual cells and their specific status regards SOH/capacity.
So, assuming that this is just a physical-chemical process, can we assume that reduction in capacity is a continuous activity or, an activity that occurs in discrete amounts or packets from time to time? I wager for a continuous activity based on my seat of the pants understanding of all this.
The observations by a car's BMS however, are stochastic and intermittent and with some noise and that appears to be what is observable by us.
In the scientific research field they would take out cells from their regulated storage and run a single well calibrated full cycle with precision instruments counting every coulomb at a fixed reference temperature. I guess we could run the official battery capacity test too, but that's a pain and wastes electricity and causes needless battery wear.
Steve446
Dusty Crophopper, M3 LR 2021 Midnight Silver
Agreed. I think it's dangerous to just take a "photoshot" of battery data at a specific time. It's better (at least from my experience), to understand how it's obtained and then to look at the data over a longer period, see its form. Then it can be treated in some way to bring out the most likely tendance. For example, the monthly "degradation" data it becomes clear when averaged on a monthly basis and over 9-12 months, I seem to have a small but clear monthly degradation rate after applying a linear regression to the data, going back more than 24 months. As I mentioned, the per cycle data is much smaller (so much so that you can't dig anything from it).
Anyhow, all that to say that this data seems to fit with and is consistent with what @AAKEE has been saying. Many comparisons stop with 50% on display as lowest SoC and sometimes disregard the temperature or other macro effects. As mentioned, I'm pretty certain I have a low degradation rate based on this factual argument. What would be interesting would be to see more data from car batteries "stored" at higher average temperatures and SoCs in order to comfort or deny that feeling
I bought my MYP in August 2023, so I used the defaults for months. I think it started at 90% for a bit and then dropped to 80% with my first software update. I started charging at 9pm for a better rate. Eventually I dropped the limit to 75% (could easily go lower) and started the charging later, at 11pm. That to put a bit less stress on it. I drive it 4-5 days a week, typically under 100 miles/day. I have the Tesla wall charger running at 48 amps, and if I want to top up to 90% or more for a long trip I can easily do that over breakfast.
Mine is an M3SR, 2023. I only charge the car every 10 days as I do not drive a whole lot, maybe 500 miles / month.
So I charge it to 100% each time as recommended by the app.
In the rare occasion, I charge to 80%. If I go away on vacation leaving the car home (plugged in) and set charging limit to 50% to ensure the battery is not drained empty due to some unexpected conditions.
So I charge it to 100% each time as recommended by the app.
In the rare occasion, I charge to 80%. If I go away on vacation leaving the car home (plugged in) and set charging limit to 50% to ensure the battery is not drained empty due to some unexpected conditions.
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