What’s the best Charge Percent

[ewoodrick]

Different sizes, different methods of ignition, but function on the same premise.




Right. The leaf "only" suffers from massive double digit degradation losses in a 2-3 year window. Active cooling would have been better than anything they did.



Actually it is perfectly valid. But believe whatever you want. Magic lithium batteries that doesn't behave like lithium *rolls eyes*

Most of the newer Leaf batteries are doing great with very little degradation now. Active cooling was NOT the reason that the batteries were updated, it was the static heat that the folks in the desert areas were seeing. Just sitting, turned off was, AFAIK, part of the problem. IT's not as if it was unique to Nissan, Tesla too has issues with the early batteries.
The issues with heating of the batteries of the Leaf were if the car was on a long journey, in a continuous charge/drive cycle. It would cut back the charging. And if I'm not mistaken, Tesla has done that as well. They now do run a special AC cycle to specifically cool the batteries before charging, but that's really new. And there have indeed been a number of folks told to let the batteries cool down before charging.
The newer Leaf's got the reputation from a single YouTuber who was essentially trying to create views. It's not a common use case at all.

 

[TMThree]

Most of the newer Leaf batteries are doing great with very little degradation now. Active cooling was NOT the reason that the batteries were updated

Riiiight. Active cooling is so unnecessary that basically everyone does it.

They now do run a special AC cycle to specifically cool the batteries before charging, but that's really new.

Depends on your climate, but you'd want the battery warm enough to accept the charge. A model 3 will use the AC to cool down the battery as it charges because heat is damaging to the cells. Something you can't do without active cooling.

The newer Leaf's got the reputation from a single YouTuber who was essentially trying to create views. It's not a common use case at all.

I guess this one youtuber managed to buy a few hundred Leafs to assemble this chart too, right.

Also we know the 30kwh battery had a firmware update to correct the recorded losses.

You can read about it here: 30 kWh Nissan Leaf firmware update to correct capacity reporting - FlipTheFleet

Basically the 30kwh batts now degrade just as slow as the smaller version, which is to say, still terrible compared to actively cooled batteries like Tesla's.

 

[woodmountain]

Fascinating the replies are. As a fellow M3 owner who drives 60 miles a day I set my limit at 85% which puts me at 215 miles. I come home between 155 and 180 remaining which varies daily based on my level of acceleration an A/C needs. Bottom line I will drive, at times, aggressively and enjoy the power never thinking twice about using more Wh/mile. I plug the M3 in daily and leave it in all weekend. The only time I push the limit is on long trips where I will drive more conservative until I am close to a charging station. So enjoy the M3 and not worry about battery degradation. As you can see there are as many opinions as their are grains of sand. Use it in good health and do what feels right.

 

[darth_vad3r]

Fascinating the replies are. As a fellow M3 owner who drives 60 miles a day I set my limit at 85% which puts me at 215 miles. I come home between 155 and 180 remaining which varies daily based on my level of acceleration an A/C needs. Bottom line I will drive, at times, aggressively and enjoy the power never thinking twice about using more Wh/mile. I plug the M3 in daily and leave it in all weekend. The only time I push the limit is on long trips where I will drive more conservative until I am close to a charging station. So enjoy the M3 and not worry about battery degradation. As you can see there are as many opinions as their are grains of sand. Use it in good health and do what feels right.

You don't have to worry about it, but you can take it into consideration -- as you obviously have choosing 85% instead of 90% (or higher), right?

No wait, you are at 215 miles at "85%"?! That's either a severely degraded MR, or an SR+ set to 90%, not 85%

EDIT: More numbers that don't add up... you drive 60 (real) miles/day, and starting at 215 dashboard miles, you end the day with 180, only having used 35 dashboard miles? That's ... unpossible?

 

[ev2therescue]

Just read through this thread. Whoa !

What I don't understand about the Model 3 manual language ("The most important way to preserve the Battery is to LEAVE YOUR VEHICLE PLUGGED IN when you are not using it") is how to reconcile this with charging percentage advice. Is Tesla saying that, regardless of the level you set your car to charge to (80%, 90%, etc.), you should still keep it plugged in even after the charge is complete? What is the purpose of doing that?

Sorry if this is a stupid question. Been doing a lot of reading on this matter, beyond this thread and even this forum, but I'm still unclear what Tesla means.

 

[Knightshade]

Just read through this thread. Whoa !

What I don't understand about the Model 3 manual language ("The most important way to preserve the Battery is to LEAVE YOUR VEHICLE PLUGGED IN when you are not using it") is how to reconcile this with charging percentage advice. Is Tesla saying that, regardless of the level you set your car to charge to (80%, 90%, etc.), you should still keep it plugged in even after the charge is complete? What is the purpose of doing that?

Sorry if this is a stupid question. Been doing a lot of reading on this matte, beyond this thread and even this forum, but I'm still unclear what Tesla means.

Purpose of doing that is for the car to run off plug power, instead of battery power, if it needs to do anything while plugged in.

 

[Dr. J]

Just read through this thread. Whoa !

What I don't understand about the Model 3 manual language ("The most important way to preserve the Battery is to LEAVE YOUR VEHICLE PLUGGED IN when you are not using it") is how to reconcile this with charging percentage advice. Is Tesla saying that, regardless of the level you set your car to charge to (80%, 90%, etc.), you should still keep it plugged in even after the charge is complete? What is the purpose of doing that?

Sorry if this is a stupid question. Been doing a lot of reading on this matte, beyond this thread and even this forum, but I'm still unclear what Tesla means.

I think it's helpful to understand Tesla's opacity in regard to battery maintenance by imagining that their motivation is to minimize service and warranty costs. There are a lot of bad things that can happen to batteries that aren't plugged in (depleting the high voltage battery, depleting the 12V battery, etc.), and useful things from keeping the car plugged in (maintaining charge, using shore power for heating, cooling and routine electrical drains). They also want to effectively market the car's range, so they're probably hesitant to say "keep it at 50%" for example, even though that may be best for long-term (years-->decades) battery life.

 

[Rocky_H]

What I don't understand about the Model 3 manual language ("The most important way to preserve the Battery is to LEAVE YOUR VEHICLE PLUGGED IN when you are not using it") is how to reconcile this with charging percentage advice. Is Tesla saying that, regardless of the level you set your car to charge to (80%, 90%, etc.), you should still keep it plugged in even after the charge is complete? What is the purpose of doing that?

The purpose of it is to dispel some really uninformed myths that the public has that came from just ignorance of how electric cars work. There are many people in the public (and I've seen it asked on this forum, too) who think that they need to go running to the car to pull the plug when it's done charging, because they believe that the charging station on the wall has no visibility to what the car is doing, and that it's just blindly, unrelentingly forcing energy into the car non-stop with no end, and that if the owner doesn't rush to pull the plug that it's going to blow up the car. I'm serious. I've actually seen people ask if that is going to "blow up" the car if they don't rush to unplug it.

So the purpose of that wording is mainly to calm people down and to encourage good habits. Plug it in as often as you feel like it, and you can leave it plugged in as long as you want--no worry at all. So that's why they are saying that. Picking a good charge limit is kind of a separate thing.

 

[ev2therescue]

Those are helpful explanations. From what I understand, you can set a percentage charging limit, so to your point @Rocky_H, the charging would stop once the limit is achieved, even if the car is still plugged in.

Thank you, all!

 

[danarcha]

I understand that the charging station stops the flow of electricity when the desired charge limit has been met. Could there be an issue however with leaving the car plugged in during a thunderstorm? If the house is struck by lightning, could any damage to the car result, or would the breakers in the home electrical box and/or charging station prevent a damaging flow of electricity to the car?

 

[XLR82XS]

I understand that the charging station stops the flow of electricity when the desired charge limit has been met. Could there be an issue however with leaving the car plugged in during a thunderstorm? If the house is struck by lightning, could any damage to the car result, or would the breakers in the home electrical box and/or charging station prevent a damaging flow of electricity to the car?

Breaker will trip.

 

[israndy]

Breakers WILL trip, but the spike can still do damage, that's what lightning arresters are for. But really? You are worried that your car is gonna be struck by lightning? Watch out for that quicksand!

My question is how bad is fast charging? People with original Model S's are at the point now where they cannot Supercharge above 95kW or even less. Some sort of statistic is tracked and after a certain number of quick charges, the car will request lower and lower speed charges to maintain the battery life. So at what rate does this kick in? 250kW? 150kW? 120kW? 72kW? 50kW? Perhaps 11kW? And how many kWh's triggers the slowdown? Perhaps it's different at different rates?

They make Urban Superchargers, it could be they are doing it for a reason, perhaps it is better long term to charge at 72kW than it is to charge at 250kW (not that my car does 250kW for more than a split second when I first plug in). So is 150kW safer than 250? If I charge with my CHAdeMO adapter at 45kW does this count against my time charging at a Supercharger and the eventual slowdown? Should I DC charge at all when I am not traveling? Is 11kW too fast, is that why I can change it to a lower amperage? Will charging at 120V extend the life of the battery?

Enquiring minds... Or enquiring mound perhaps in my case.

 

[Rocky_H]

@Randy Spencer All of those questions, about throttling from fast DC charging are addressed here, in this thread about charge speed throttling, not for this thread about charge limit %.

If you fast charge, Tesla will permanently throttle charging

 

[drtimhill]

I’ve played around for the last year, and all I need is 70% except when I’m going on an extended journey. I do let the car go down to 40% or so before I plug it in again.

 

[israndy]

I’ve played around for the last year, and all I need is 70% except when I’m going on an extended journey. I do let the car go down to 40% or so before I plug it in again.

That's what I was doing and will do again once my mum'in'law passes. I have been doing the 86% charge level as that is where the free CHAdeMO near me starts to slow down dramatically during a charge and it's enough to get us to her place and back every day.

All of those questions are addressed here

If you fast charge, Tesla will permanently throttle charging

Thanks for the link. I guess I was getting a little off-topic, I see charge level and charge speed as two sides of the same coin

 

[Rocky_H]

Thanks for the link. I guess I was getting a little off-topic, I see charge level and charge speed as two sides of the same coin

I'm really sorry that thread is over 100 pages long, but every aspect of it has been discussed in there, and I can summarize from a few of the questions you asked here.

If I charge with my CHAdeMO adapter at 45kW does this count against my time charging at a Supercharger and the eventual slowdown?

Yes it does. The very first originator of that thread who revealed that issue had it come up from a huge amount of CHAdeMO charging, but very little Supercharging. Since CHAdeMO is limited through the adapter to only about 45kW, it's not a very high power level. That is the unfortunate oversimplified approach that Tesla took to it, where it just looks at a total amount of kWh of energy that have been added using DC charging, which they just all lump together as high power. Since speeds shift so much in Supercharging, I guess it would have been harder to try whether it was above a certain kW power level or something, whereas whether it's DC or not is an easy binary mode to track.

And I should also add that this isn't guessing. In that thread, he posted the screen shots of someone from Tesla engineering admitting they do this and listing the conditions that trigger the power limiting.

So any form of AC charging at home or on J1772 stations will not count toward that and is already extremely low power from the battery's perspective.

What's affected: That thread first started to see it on the early 90 kWh batteries in the S and X, but I think it did also start to get observed in most of the others, like the 75, 85, and 100. But as far as I know, the newer form of battery packs with the 2170 cells in the Model 3 and Y have not been affected by this yet. It is a very revamped battery system, so they may have addressed that somehow.

 

[TimothyHW3]

What @Dr. J said is pretty much why Tesla suggests keeping the car plugged in.
A) Tesla wants to avoid you going on a vacation and having sentry on killing the battery.
B) It keeps the car in a good range - inexperienced drivers will never have range anxiety.
C) it helps if you run sentry mode on and most people will not see how much it actually uses.

The main problem you will run in, especially with Model 3, not so with S and X, is that this leads to an unbalanced BMS(battery management), and at the end the car will report less range. But since most people drive in % and never or almost never drive long ranged, they will not see the missmatched BMS.

Basically this is a (kind of bad, at least on the Y and 3) advice for EV- novices from Tesla as it leads to tons of "my range is dropping" threads

I can tell you what I do: I used to charge when I went to about 20-30% and charge to about 75%. I also did a lot of Supercharging from 5% to about 85%.
Then I started charging only or mostly between 10-20% and 90%(try to drive off right at 90% and never keep the car for longer periods above 75%)
Never keep the car plugged in in-between and always charge right away below 20% and get driving at 90%.

So far both BMS and Battery are working great and I have about 307 rated miles at 100% out of310 brand new. 14 months and 18,000miles/30,000km+
I have about 60% DC Fast charging vs 40% AC, so that is also not ideal, but it works

 

[israndy]

Is there a drive it down to zero and then charge it up 100%, twice, that fixes the BMS mismatch on the 3&Y? Something like that?

 

[Candleflame]

Is there a drive it down to zero and then charge it up 100%, twice, that fixes the BMS mismatch on the 3&Y? Something like that?

there is currently no evidence that deep discharges charges recalibrate displayed range. we have got anecdotal evidence that keeping cell voltage above 4v (usually above 75%) calibrates the pack over a few weeks and we have very good evidence that on the model S plugging it in every day and letting it charge to 92% (dayrange) leads to the least degradation at least in the short term.

 

[TimothyHW3]

Is there a drive it down to zero and then charge it up 100%, twice, that fixes the BMS mismatch on the 3&Y? Something like that?

Not like that, but I have seen people who had drop in range gain back a lot of it back by simply consistently charging only around 10-90% for about 2 months.