So apparently, always charging to 100% is OK (?)

[masmole]

I was chatting with my SA today, finalizing plans for the delivery of my new GTS tomorrow, and he mentioned something I found very interesting yet remain slightly skeptical about. I was asking about recommended charging practices and even referenced a thread on these forums, specifically Squiden’s words of wisdom, to see what his thoughts on this topic was.

My SA is a very knowledgeable person in general, which is surprisingly uncommon with car sales personnel that I’ve encountered over the years, and his family has owned and operated this Porsche dealership for over 30 years. so he knows his Porsche stuff.

He basically said that charging to only 85% is not necessary because Porsche has already designed the Taycan to never charge to the full capacity of the battery even when it says 100%. All EVs leave this headroom to some degree, but he claims the Taycan does so even more than others. Apparently when it says 100% on the Taycan’s display, it’s really more like 90%. So if you charge to “100%” every time, you’re really only charging to around 90% which is within a stone’s throw from the magic 85% number. So if I charge my Taycan to 85% as often recommended by many here, I’m really only charging 85% of 90% which is more like around 75% (check my maths lol).

My SA said to just enjoy the car, don’t worry about charging so much and just charge to 100% when you can, and avoid fast-charging unless really necessary. He says regular home 240V AC charging with 40A or so to 100% is already optimal for battery health because Porsche in all their German wisdom have already sorted this out for all Taycan owners so that they have one less thing to worry about.

Makes a lot of sense to me. I think I’m sold.

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[daveo4EV]

well if the 85% number is 85% of the "fake" 100% it's still 15% more SOC than 85% - not a stones throw

this could be true - it could also not be true...

personally (with no data) I believe this not to be true

one reason - there is _NO_ regen when you're at 100% - i.e. when you're charged to 100% Porsche's blended braking pulls way way way back on the max regen level - which if there was still SOC head room in the battery I would suggest Porsche would be less aggressive with it's max regen amount when the battery was fake-full

what probably _IS_ true is that honestly it probably won't make that much of a difference - the issue with charging to 100% is _NOT_ charging to 100% in of itself - it's charging to 100% and then letting the car sit at that charge level for a long time - no one will say exactly what duration a "long time" is - but it's certainly not just a few days - more like weeks/months - and charging to 100% and then continuing to re-charge to 100% from 99% is also very very hard on LiON cells…and this is quite hard to cause to happen with an EV since when an EV is not charging, it's not charging (even when it's plugged in) - unlike a lot of other consumer devices - EV chargers cut off power when the battery is charged and they do not sit there and continue to push power into the battery (unlike power tools, cell phones, laptops)

I'm not inclined to agree with your dealer's analysis, but I am inclined to believe it won't make that much difference - and Porsche recentlly admitted with their Macan briefings that

1. Taycan fleet is doing great with batteries
2. they were overly conservative on their "hold backs"
3. Macan will run "closer to the edge" in terms of raw capacity vs. usable capacity based on data they have from the Taycan fleet and advances in battery tech

I'd suggest charging to 85% vs. 95% is honestly no impact - and 5% of Taycan battery is about 4 kwh or 12 miles of range - probably charging to 95% will have virtually no impact on battery longevity and the extra 12 miles of range you're losing by not charging to 100% should not be consequential - honestly - ever…

however it's your car, it's your battery, and Porsche warranties it for 8 years/100,000 miles - use it as you see fit - the Battery Management Software (BMS) will prevent any actual damage from occuring since it's role is keep the battery in warranty parameters. There is honestly very very little we as owners can do "to" the battery - it's largely outside our control.

 

[daveo4EV]

also it's worth noting there is more problems will getting a LiON cell close to "true/raw/physical" 0% vs. "true/raw/physical" 100% - so every battery engineer I've ever talked to (phone, lap top, automotive) says there is more buffer on the bottom than the top…overcharging the battery damaged long term capacity - but solves itself when it's discharged having lost some capacity - letting a battery get to raw 0% bricks the battery - never to be charged again…

I would believe 100% charge on Taycan is close to true 100% with very little hold back for "buffer" - but that there is a healthy buffer at the low end to prevent replacing entire batteries rendered dead by allowing full discharge…

but honeslty all this stuff is trade-secret-sauce and one of the few differentiating aspects of EV's between vendors and their battery engineers - and also can change with a flick of a software update - how the battery is managed is entirely controlled by software - and one software update can change _ALL_ the rules (rules for which there is no public disclosure - corporate confidential is an understatement here)…

use your battery as you see fit - cause honestly I believe 100% there is too much software involved for us to have any actual control - it's all being managed for us behind the scenes.

 

[masmole]

Very good points! That settles it then… I will always charge to 88%. Just because I like that number.

 

[daveo4EV]

Very good points! That settles it then… I will always charge to 88%. Just because I like that number.

in honor of your actions I'm going to change my charging % to 93% 89% because it's

1. arbitrary
2. not 100%
3. more than 85%
4. and a prime number

beware the next owner - they will now know I've done this to their battery when I trade the car in.

Edit: I was told there would be no math - my original choice of 93% is/was _NOT_ a prime number - the only primes below 100 and above 85 are 89 & 97 - so I've amended my posting.

 

[MrBlueSky]

in honor of your actions I'm going to change my charging % to 93% because it's

1. arbitrary
2. not 100%
3. more than 85%
4. and a prime number

beware the next owner - they will now know I've done this to their battery when I trade the car in.

I was with you up until No.4……….

 

[PeterKm]

I asked my SA the same question on Monday as I was planning the first charge of my GTS and the My Porsche app stated I should charge up to 85%. He said that on home charging its ok to leave to 100% but when using the high speed Infinity chargers I should only go up to 85% because of the load put on the battery.

 

[Steve R]

Terrible analogy but these batteries are a bit like a propane tank.....you never fill it completely and have to leave some room for good measure. I've chatted with battery guru's and they'll all tell you different things. Some say these batteries won't benefit from going 80-85% full and others say it will help.

Fact is, what may be more important is to let the battery run down to 20% and not perpetually keep it between 65-85% by plugging it in after every drive.

Furthermore, the guys who've been building these things say many of these batteries are lasting far longer than projected with dramatically less degradation as expected. The technology is still too young to know for certain.....but what I do know for certain is that if you can afford one of these cars, you can afford not to stress the details.

 

[Sidicks]

in honor of your actions I'm going to change my charging % to 93% because it's

1. arbitrary
2. not 100%
3. more than 85%
4. and a prime number

beware the next owner - they will now know I've done this to their battery when I trade the car in.

93 is not a prime number.

93 = 3 x 31!

 

[W1NGE]

I was chatting with my SA today, finalizing plans for the delivery of my new GTS tomorrow, and he mentioned something I found very interesting yet remain slightly skeptical about. I was asking about recommended charging practices and even referenced a thread on these forums, specifically Squiden’s words of wisdom, to see what his thoughts on this topic was. My SA is a very knowledgeable person in general, which is surprisingly uncommon with car sales personnel that I’ve encountered over the years, and his family has owned and operated this Porsche dealership for over 30 years. so he knows his Porsche stuff. He basically said that charging to only 85% is not necessary because Porsche has already designed the Taycan to never charge to the full capacity of the battery even when it says 100%. All EVs leave this headroom to some degree, but he claims the Taycan does so even more than others. Apparently when it says 100% on the Taycan’s display, it’s really more like 90%. So if you charge to “100%” every time, you’re really only charging to around 90% which is within a stone’s throw from the magic 85% number. So if I charge my Taycan to 85% as often recommended by many here, I’m really only charging 85% of 90% which is more like around 75% (check my maths lol). My SA said to just enjoy the car, don’t worry about charging so much and just charge to 100% when you can, and avoid fast-charging unless really necessary. He says regular home 240V AC charging with 40A or so to 100% is already optimal for battery health because Porsche in all their German wisdom have already sorted this out for all Taycan owners so that they have one less thing to worry about.

Makes a lot of sense to me. I think I’m sold.

I think we are all aware of the battery protection and that 100% is only ever 100% of around 90%. I think at one point we understood that there was 15% in reserve and used for protection purposes but since 2020 we now understand this to be a little less. That's why there is a gross battery capacity and a net capacity where the latter is what we get to use. In the case of the Taycan with Performance Battery Plus that's 93.4 KWh and 83.7 kWh respectively. The difference (10%) being reserved for battery management and protection.

This indeed is normal practice for EV manufacturers but Porsche for whatever reason have gone ultra conservative. We understand that the forthcoming Macan EV will open up more of the gross battery capacity to help extend the available range.

Notwithstanding any of that and in case of warranty challenges we feel obliged to comply with the Porsche advised 80-85% daily charge and generally only 100% if used on that day.

 

[Gnasher]

Spoke to to Porsche emergency service guy who said the reason NOT to charge to 100% is indeed the reg as mentioned by daveo!

If you charge to 100% and then go down a hill the regen will try and charge the battery which could result in damage to it as there is no capacity.

I guess if you go to 100% then don‘t have regen on.

 

[Bobzilla]

93 is not a prime number.

93 = 3 x 31!

91? Just a mental guess, not run all the permutations.

 

[Sidicks]

91? Just a mental guess, not run all the permutations.

91 = 13 x 7!

 

[Fish Fingers]

I am going to stick to what The Porsche app now says - 85%.

I have more trust in the Porsche Mothership than any dealer - as I have found car sales people in general have lower knowledge than us 'enthusiasts' on forums.

I also question the above post that Says its important to run it down to say 20% and not keep topping it up regularly?

 

[BigBob]

I think we are all aware of the battery protection and that 100% is only ever 100% of around 90%. I think at one point we understood that there was 15% in reserve and used for protection purposes but since 2020 we now understand this to be a little less. That's why there is a gross battery capacity and a net capacity where the latter is what we get to use. In the case of the Taycan with Performance Battery Plus that's 93.4 KWh and 83.7 kWh respectively. The difference (10%) being reserved for battery management and protection.

This indeed is normal practice for EV manufacturers but Porsche for whatever reason have gone ultra conservative. We understand that the forthcoming Macan EV will open up more of the gross battery capacity to help extend the available range.

Notwithstanding any of that and in case of warranty challenges we feel obliged to comply with the Porsche advised 80-85% daily charge and generally only 100% if used on that day.

I wonder if in 8 years time and batteries are degraded somewhat if it would be possible to release some of the buffer to give a little range back. I suspect i know the answer, but would make sense to a luddite like me!

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