Charging to 100%, why not?

[unbiased]

Sorry guys, maybe has been discussed previously but close to getting a GTS. Simple question to more experience owners, why not charge to 85% and not to 100% every time? Hear me out, on other cars (or electronic devices per se) like Tesla you dont want charge to 100% every time to preserve the battery, HOWEVER, Tesla allows you to use 100% of the battery capacity. On the Taycan only roughly 90% is available to the driver (dont have the exact numbers), remaining 10% are a buffer locked by Porsche.

That begs the question, even if you charge to 100% you never actually charge the battery capacity technically to 100% but only 90%. So why the caution?

If anyone is wondering why ask this question… live close to an EA charger and would charge the car for free…makes more sense to charge to 100% to have less trips to the charger.

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[Vim Schrotnock]

One possibility is if they need to increase your battery capacity to satisfy the 10 year warrantee, they could just release the additional capacity rather than replacing the entire battery. This might be worth a lot more than allowing the whole enchilada from day 1.

 

[beefster]

Please do not charge to 100% at a DC fast charging station like EA unless absolutely necessary and/or multiple stalls are available. The charging speed slows down quite a bit above 90% coupled with availability and congestion at EA chargers is already bad enough. Above 95% it's nearly slow enough that a home or work AC charger would be about the same speed.

As to why not 100% everytime, the degradation, however minimal just isn't worth it for day to day usage. Starting a roadtrip on the other hand? No worries charging to 100%

 

[Jhenson29]

That begs the question, even if you charge to 100% you never actually charge the battery capacity technically to 100% but only 90%. So why the caution?

That 10% isn’t all at the top end. Some of it is at the bottom. Imagine the usable range as something more like 5-95 of capacity, although I don’t know the exact division.

 

[DougFrisk]

If you go here: "Best practice EV charging for longer battery life" - video | TaycanForum -- Porsche Taycan Owners, News, Discussions, Forums and jump forward to 16:30 it explains in some detail why the best longevity for the type of cells used in the Taycan is to generally keep the individual cells between about 30% and 75% charge and to charge often.

75% charge at the cell level is a bit over 80% on the Taycan charging screen. Based on that information I've chosen to set the target max charge to 80% and charge every day. Generally we're putting in 2 to 10 KWh per day. I have a 48 amp charger, so if I want to take a longer trip I can hit the direct charging button on the app and add that last 20% in less than 2 hours.

In theory, that should help to reduce aging of the battery. I won't know for a few years of course, but the battery state of health hasn't changed since I last reported it. The battery should last at least through the warranty period if you do charge to 100% all the time so if your plans don't include keeping the car for more than a decade charge away.

What makes sense is to install a charger in your garage. Every day you wake up with 200 or so miles of range and you don't need to think about "filling up" unless you're road tripping. The probability of loving your EV experience is highly correlated with having a convenient daily charging capability. The probability of hating your EV experience is highly correlated to doing all of your charging at HVDC stations. Free charging at EA to 100% doesn't cost in dollars, but it has a significant cost in time.

 

[unbiased]

It will be a leased car…long term viability not a concern

 

[DougFrisk]

It will be a leased car…long term viability not a concern

I would still highly suggest getting a decent charging station installed where you park. By decent, I mean 5 KW (240 volt 30 amp) or more.

 

[arijaycomet]

HOWEVER, Tesla allows you to use 100% of the battery capacity. On the Taycan only roughly 90% is available to the driver (dont have the exact numbers), remaining 10% are a buffer locked by Porsche.

Be aware that there are other reasons and advantages to having more of the top/bottom locked out by the automaker. For example, if you have ever charged a Tesla to 100% then you'll find you accidentally almost run into people expecting the 1-pedal regeneration to work "as normal" - but it doesn't. Why? Because at 100% SOC there is no where for the battery to recharge, so it disables this feature. Additionally, taking the battery down to that lowest point is really bad for the battery, and can cause a complete failure. Another reason to cap the top end? Faster DC fast charging (it provides more area under the curve, since you're losing 5% top and 5% bottom let's say, so you can charger "faster" deeper into the available realm).

With ALL of that said-- a leased EV does give one justification to charge to 100% and throw caution to the wind. However if there was a battery failure during your ownership, and you were charging past the recommended SOC, it could stand to reason that this would show up in logs, and they could void the warranty. Somehow doubt any large auto maker would do this (that is more of a Tesla kind of flex). But still, it's like using the wrong octane fuel, etc. Even if the car is only yours for a lease, wouldn't you like to be a better person and pay it forward? My two cents...

PS: As other have indicated, fast charging beyond 80% will be bad on so many other levels. Perhaps the biggest is your use of time. Getting for 80% to 90% is slow, and 90% to 100% even worse. You'll be waiting there forever. But for whatever it is worth, I know a few people who do this, on Tesla or similar vehicles, and overall it has been fine for the car in their short ownership period; but certainly not ideal.

 

[Tooney]

If anyone is wondering why ask this question… live close to an EA charger and would charge the car for free…makes more sense to charge to 100% to have less trips to the charger.

The first time you charge to 95-100% at an EA charger (or any DC fast charger) you will have learned the answer to your question.

 

[hifi239]

Congratulations on going from a Toyota to a Taycan GTS! Only thing I have to add is that you won't be going to 100% in the free 30 minutes on any EA charger I know of. You might get 50 or 60 kWh free. I assume you have the big 92kWh battery and so you'll go roughly 20-80% free, which is exactly what you want: it's fast, it's good for the battery, it's free. That, however, is contingent on finding a working EA DC charger that isn't derated, or broken, or has a line of 10 Bolts and Ionic5s . (Get a Level2 at home)

 

[andix]

First of all: congrats!

All modern EVs differentiate between a net and a gross battery capacity.
WIth the perf battery, net is 83,7 KWh on the Taycan.

100% means you charged to 83,7 KWh, not 100% of the gross 93,4 KWh.
(That's similar on other EVs, including the Tesla.)

There are various articles on the chemistry and physics, but a short guidance:

• usually (= "daily") between 20-80% (figure readings in car/ app)
• if you immediately leave for a longer trip, occasionally charging to 100% doesn't do harm
  (as you start to unload the electrons immediately by driving)
• occasionally going below 20% doesn't do much harm (not much below 10% though)
• slower charging is better (heat stress, contact corrosion etc.)

If you follow this, your battery will have 100% after 3 years (as tested by many magazines).

 

[timc3]

It will be a leased car…long term viability not a concern

What about for the next owner(s) and to make sure that the batteries don't wear prematurely?

 

[Bognar67]

@andix
There are various articles on the chemistry and physics, but a short guidance:

• usually (= "daily") between 20-80% (figure readings in car/ app)
• if you immediately leave for a longer trip, occasionally charging to 100% doesn't do harm
  (as you start to unload the electrons immediately by driving)
• occasionally going below 20% doesn't do much harm (not much below 10% though)
• slower charging is better (heat stress, contact corrosion etc.)

If you follow this, your battery will have 100% after 3 years (as tested by many magazines).
[/QUOTE]
Show me please one single car with 100% SoH not after 3Y but 3 months... or a relevant article about it in a "magazine". Simply not possible by the physics of any recent battery chemistry. https://www.taycanforum.com/forum/threads/baseline-for-hv-battery-soh-performance.12815/

 

[simcity]

That begs the question, even if you charge to 100% you never actually charge the battery capacity technically to 100% but only 90%. So why the caution?

Charging to full is not the issue - if you use it immediately - within hours, rather than letting it sit for days or weeks.

Leaving the battery in a very high state of charge for long periods is what ultimately reduces the state of health and capacity of the battery long term.

 

[Bognar67]

Charging to full is not the issue - if you use it immediately - within hours, rather than letting it sit for days or weeks.

Leaving the battery in a very high state of charge for long periods is what ultimately reduces the state of health and capacity of the battery long term.

True. Same rule below 20%. If you charge immediately no problem.
Just do not let to sit it long below 20% and above 80-85%.

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