How many charge to 100%

[Kingske]

lithium batteries are the same, the chemistry of Taycan and Tesla aren’t diffe, is like saying that an IPhone and Samsung phones should be charged in a differ way. You can read research papers about Lithium battery care that validates 90%. In fact apple recommends charging up to 90%. Porsche is very conservative and the end is the first EV and they are super careful.

Porsche actually reduced its recommended target SoC% from 85% for MY2020 to 80% for MY2021. It seems to me that such a move might be based on data rather than on initial conservatism.

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[JimBob]

You can always use your own judgement but it just makes sense to follow the manufacturers recommendations to get the best performance out of them.

A number of factors have been identified as causing degradation of lithium ion batteries with the two main ones being high temperatures and repeated deep discharging.

If you live in the desert southwest and your car is parked in the blazing sun all the time, your battery is going to degrade faster than someone who lives in the cooler north.

If you regularly run your battery down from 80% to 5% and charge back up, your battery will age faster than someone who uses shallower discharges. Say from 80% to 20%.

Then there are a bunch of additional factors that will cause them to degrade.

 

[benver]

Porsche actually reduced its recommended target SoC% from 85% for MY2020 to 80% for MY2021. It seems to me that such a move might be based on data rather than on initial conservatism.

If I read the "Technical Information document 48/21 ENU 2708 2 Replacing High-Voltage Battery on Model Year L (2020) Vehicles" correctly, it seems that there is a chemical difference between the MY2020 and MY2021 batteries.

A quote: "New high-voltage batteries with a modified cell chemistry are used on Taycan vehicles from model year M (2021) onwards.".

Maybe that's the reason for the different 80% / 85% advise?

I found this document on the NHTSA website www.nhtsa.gov Do a search for your vehicle in the Safe Cars Save Lives search box and scroll down on the search result page till you see Manufacturer communications. Click on it, scroll down, select Electrical System, the date of the document is April 6th, 2021.

 

[Kingske]

If I read the "Technical Information document 48/21 ENU 2708 2 Replacing High-Voltage Battery on Model Year L (2020) Vehicles" correctly, it seems that there is a chemical difference between the MY2020 and MY2021 batteries.

A quote: "New high-voltage batteries with a modified cell chemistry are used on Taycan vehicles from model year M (2021) onwards.".

Maybe that's the reason for the different 80% / 85% advise?

I found this document on the NHTSA website www.nhtsa.gov Do a search for your vehicle in the Safe Cars Save Lives search box and scroll down on the search result page till you see Manufacturer communications. Click on it, scroll down, select Electrical System, the date of the document is April 6th, 2021.

Interesting possibility. Bedankt hiervoor.

 

[atebit]

Tesla claims that their Battery Management System takes the human out of the equation...all you need to do is keep it plugged in. Maybe Porsche’s BMS isn’t as good yet?

 

[kort]

Tesla claims that their Battery Management System take the human out of the equation...all you need to do is keep it plugged in. Maybe Porsche’s BMS isn’t as good yet?

tesla recommends not charging beyond 90% for daily usage, porsche recommends 80%, not really much different and I don't think it has anything to do with battery management.

 

[JimBob]

Someone might be able to double check this as it could help on this 80 or 85% charging issue.

It sounded odd that the recommended charging level for the newer 2021 model would be reduced from the 2020 model. Normally you expect things to improve.

If you refer to the WMA5 update for the MY2020, on page 24 it talks about a new online owners manual dated March 5, 2021 for the 2020 Taycan's. Also refer to pages 31-34 of the WMA5 update. It sounds like you are also supposed to get a new paper owners manual.

I haven't had the update yet so can't check. Someone might be able to check see what the new version of the manual says about this.

 

[atebit]

tesla recommends not charging beyond 90% for daily usage, porsche recommends 80%, not really much different and I don't think it has anything to do with battery management.

I guess I meant in terms of “just leaving it always plugged in” vs “only plug in when you get down to a certain percentage SOC”

 

[kort]

I guess I meant in terms of “just leaving it always plugged in” vs “only plug in when you get down to a certain percentage SOC”

in both the taycan and teslas if you keeping it plugged in doesn't mean that it is charging. the car will charge to the level you've chosen then stop. you are misusing the term battery management system which refers to how the car actually manages the nodes or batteries that make up the main battery.

 

[atebit]

So then who do you think is making the incorrect statement, Tesla saying to leave the car plugged in all the time or (at least anecdotally) Porsche saying to only charge when you drain down to a certain SOC? The battery chemistries between the two brands can’t be that radically different, can they?

 

[epirali]

So then who do you think is making the incorrect statement, Tesla saying to leave the car plugged in all the time or (at least anecdotally) Porsche saying to only charge when you drain down to a certain SOC? The battery chemistries between the two brands can’t be that radically different, can they?

This has been covered elsewhere. It’s not about when you plug in rather what SOC you leave the car and shallow vs deep discharges. Tesla wants the car plugged in because they have vampire battery drain issues and if left unplugged long enough the car will brick the battery (unrecoverable). So they promote leaving car plugged in as a “feature.” Porsche doesn’t have that issue. And both cars allow you to set the maximum charge. Porsche also allows setting a MINIMUM charge.

So it’s best to follow each manufacturers recommendations. I set a minimum of 40% for my Taycan, I charge to 60% for commute and charge higher as I need for range.

All current EV battery chemistries are minor variants of the same design.

 

[benver]

So then who do you think is making the incorrect statement, Tesla saying to leave the car plugged in all the time or (at least anecdotally) Porsche saying to only charge when you drain down to a certain SOC? The battery chemistries between the two brands can’t be that radically different, can they?

Could it be the Porsche advise to not keep the car plugged in has to do with the 12V battery dying issue? In other words, when the car is plugged in it is "talking" to the wall charger now and then and under some specific circumstances the 12V is drained without being charged by his/her big brother.

 

[atebit]

I guess to get the minimum setting I would need to set up a timed profile (I’m just using the general now), so I’ll have to look into that. I have an 18KW PV system with kickin’ southern exposure, and no TOU billing options here so it doesn’t really matter when I charge.

 

[kort]

I guess to get the minimum setting I would need to set up a timed profile (I’m just using the general now), so I’ll have to look into that. I have an 18KW PV system with kickin’ southern exposure, and no TOU billing options here so it doesn’t really matter when I charge.

the timing feature can introduce some wonkiness to the process. if you have no concerns about the time that you charge I'd recommend not using that feature

 

[atebit]

Agreed, but I guess my goal (which is hopefully consistent with this thread) is to be as compliant as possible with the manufacturer’s charging guidance. Tesla’s was “always keep it plugged in”. That was easy, pull into the garage & plug it in. If Porsche’s saying to only charge between X - Y %SOC, then I’d like the car to manage that if possible so I can again just plug it in upon returning home & forgetting about it. So it seems like the only way to do that is with the wonky profiles.

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