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

[W1NGE]

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.

Would it not just simply dissipate as heat and the tech would simply say "no room at the inn" rather than lead to damage? Most people probably never switch regen off and if you live your life in Sport / Sport Plus then it is always on. I'm sure Porsche would have put appropriate protection in place if this was a real concern.

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[W1NGE]

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!

My guess is that the 10% is never the same 10% and so each cell has a role to play in the protection measures.

My further guess is that some of the recent range extension (not all of us have seen it yet) will be in part due to relinquishing some of the 10% reserve rather than anything overly clever.

After 8 years I wouldn't be surprised if cells are swapped out.

 

[Deleted member 7514]

Would it not just simply dissipate as heat and the tech would simply say "no room at the inn" rather than lead to damage? Most people probably never switch regen off and if you live your life in Sport / Sport Plus then it is always on. I'm sure Porsche would have put appropriate protection in place if this was a real concern.

You would think right ?

code something like IF battery = 100% then REGEN OFF

 

[W1NGE]

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?

Its always said that but if you read the Owner's Manual and / or Porsche Good to Know it will be contradicted and daily charging to 80% is the recommendation.

The other anomaly is the 85% high water mark on the battery graphic both on the app (and website) and in the lower display when the battery charge is displayed.

Some good old left-hand / right-hand voodoo at play here!

 

[Jhenson29]

Would it not just simply dissipate as heat

In very small amounts. But to do anything meaningful there would need to be an additional component, like a resistor, to dissipate the heat over to actually do that.

It’s a bit like taking the friction brakes off and asking if it can just dissipate as heat. Yes, a little. But not much (relatively).

 

[Jhenson29]

code something like IF battery = 100% then REGEN OFF

It would be implemented as a negative current limit in the inverter control and would adjust based on capacity.

 

[Valen]

I got a race oriented EV motorbike as a daily (same bike as the current season E moto GP) and had the opportunity to chat about battery with a tech from the company.

Battery wise, the most important thing is not to charge to 80 or 85 or 91%, it is to charge sometimes to 100%. The reason behind this is called cell balancing. If you never charge to 100, some cells will never be "stimulated" and it will impact more your battery.

What "hurts" the battery isn't slow charging at home, it's fast charging because the heat generated will stress the cells specially on last 5%. Charging a battery is like emptying a bottle in a jar. The faster you go, the harder is to not to make a mess.

On top of this the Taycan, as all EV, have a buffer so basically your 100% charge is more a 90% of the real capacity.

 

[Jhenson29]

On top of this the Taycan, as all EV, have a buffer so basically your 100% charge is more a 90% of the real capacity.

90% of the capacity is user accessible. But there’s nothing that says the other 10% is all at the top. It almost certainly isn’t. So, charging to 100% doesn’t mean you are only at 90% of the entire battery. It’s more.

 

[Valen]

90% of the capacity is user accessible. But there’s nothing that says the other 10% is all at the top. It almost certainly isn’t. So, charging to 100% doesn’t mean you are only at 90% of the entire battery. It’s more.

Yes the 90% wasn't scientific it was just a shortcut. All in all as long as the "jar" isn't really full, you're good

 

[Frankhy]

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 your SA is correct. When I took deliver of my Audi E Tron 2 years ago I was told the same thing. I can charge to 100% all of the time as Audi don't let you access the full 100% anyway, they only let you access 85% in order to protect the battery.

 

[FlyingPoint]

I know nothing about BMS or battery physics, however there is one thing I do know:
Porsche would never have permitted "direct charging (100% SOC) if they believed it would cause them to replace batteries under the warranties written in various countries.

 

[kort]

my rules are to avoid letting the car sit at 100% for an extended period of time. on the lower end the same, I don't let it sit below 10% for an extended period of time. I charge to 100% as needed to begin long trips, and to 90% on a regular basis.

that said, when my tesla was rear ended it was in the body shop for 5+ months without being charged because the charge port was damaged, I don't recall what the SOC was when it was hit but it was at least 70%, upon repair the car charged and the battery system showed no ill effect from not being charged for so long of a time.

I place little value on the opinions of the tech aspects of the cars offered by sales people. 98% have very little good knowledge of the car.

 

[Windpower]

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).

The issue is that none of the EV manufacturers or the manufacturers of the battery cells have enough long term experience with LiO batteries to definitively make standards for charging practices. So we rely upon recommendations which "seem to work" to extend battery life.

I own a Tesla and Tesla owners for years were told to 'ABC' (always be charging) which means you should be charging every day without regard for the state of charge of the battery. This essentially topped off the battery to 85% every day.

More recent advice has been to keep the battery charge between 20% and 85% of the battery capacity for best battery health. So instead of ABC, charge when SOC gets to 20%.

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%.

While this sounds logical, there is not enough long term data to know if this is correct or not. In the meantime, until studies are conducted, I still follow the "85% to 20% daily and 100% when you are leaving on a long trip" guidance. And I also believe that slower AC charging is 'gentler' on batteries than fast DC chargers so only use a DC fast charger when necessary.

 

[DJ-UK]

I got a race oriented EV motorbike as a daily (same bike as the current season E moto GP) and had the opportunity to chat about battery with a tech from the company.

Battery wise, the most important thing is not to charge to 80 or 85 or 91%, it is to charge sometimes to 100%. The reason behind this is called cell balancing. If you never charge to 100, some cells will never be "stimulated" and it will impact more your battery.

What "hurts" the battery isn't slow charging at home, it's fast charging because the heat generated will stress the cells specially on last 5%. Charging a battery is like emptying a bottle in a jar. The faster you go, the harder is to not to make a mess.

On top of this the Taycan, as all EV, have a buffer so basically your 100% charge is more a 90% of the real capacity.

I agree. I still have my iPace and Jag issued a statement saying if you only ever charge to 85%, you are more likely to cause damage. The software is designed to do cell balancing, so charging to "100%" at home is advisable. I have charged to 100% to date on my iPace (just over three years, whilst I wait for my Taycan...), don't see any degradation. Never charged to 100% on CCS Rapids.

 

[Fish Fingers]

Quick question..
Are there a lot of different battery manufacturers?
Just interested, with the different guidance coming from different car makes.

And does the battery tech vary much?

End of the day, I suppose it because its all new that we want to know.
With ICE cars, we all knew you shouldn't rev a cold engine, not ride the clutch, not force the gears etc etc
Some people were sympathetic, but many couldn't give a flying fook as they didn't know or care for whatever the reason.
I suppose EVs will be just the same and most of us are in the' sympathetic' camp (enthusiasts).

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