OK to full charge to 100% regularly?

[Rob70]

So quick question. The general consensus seems to be, charge to 85% unless doing a long run in which case charge to 100%. This seems consistent whether Porsche or other EVs. However, when I discussed with my Porsche dealer he mentioned that it’s perfectly fine to charge to 100% regularly if preferred. The logic being that Porsche blocks off part of the max capacity of the battery anyway so charging to 100% is not an issue.

What thoughts do folks have on this?

thanks.

Hi, I collected my 4s last Saturday and brought up the charging debate. They were very clear that they saw no issues in charging regularly to 100%!!

like you guys concerned about battery life, so will still to the 85%.

Sponsored

 

[feye]

I am speaking about charge capacity only not charge rate. However, there is a correlation between the decline in charge rate and the stress the battery is undergoing.

When the battery is at 30% capacity it can take all 270KW of charge rate, as it approaches 100% the charge rate goes down to 10 to 20 kw. The battery chemistry is holding back the 270 kw of charge capacity (FRICTION) down to a trickle. That is what causes the battery temp to rise, all those electrons being packed in.

This study suggests the safe temperature for lithium ion batteries is -20 to 60 degrees Celsius.
https://www.sciencedirect.com/science/article/pii/S1002007118307536

While my background is not specifically in battery chemistry I do audit, maintain and deploy UPS battery packs for server farms, for about 20 years.

Again, according to this German YT the key to long life and range of battery is to charge it slowly.

Do UPS maintain a buffer in the battery packs?

 

[feye]

...a few times a month to 100% isn’t going to hurt if you want the range and you drive it fairly soon after it reaches 100%. So just enjoy the car and charge it within reason how you want to

That is exactly my thinking, it's a battery not a raw egg!

 

[NormF]

The owner’s manual says 85% so suggest you stick to that, which is more authoritative than a dealer. Except of course when you are going on long road trips and then 100% is OK to max out the range.

 

[Scandinavian]

Again, according to this German YT the key to long life and range of battery is to charge it slowly.

Make a Google search for Jeff Dahn, who is probably the leading authority on Li Ion batteries. I would follow his advice rather than YouTuber from Germany!

I think he will agree with you that charging at slow levels like AC charging will prolong the life of the battery in general. However he seems to recommend to only discharge the battery to 50% and charge it frequently to low levels, not 100%! The chemistry in the battery seems to take a beating at high charge levels, however you charge.

Here is a link to a presentation of the new battery he has been involved with.

 

[feye]

Here is a link to a presentation of the new battery he has been involved with.

Thank you!

25:00 Exactly supporting my argument! I get almost 400km range every cycle. My driving profile is about 10000 km per year. I expect to own the car for about 6 years. Therefore, I need about 150 charging cycles, which is just the highlighted area. Will I be able to even notice degradation?

I picked the 90% charged because realistically, I will charge from 5% to 95% in relation to the gross capacity of the battery, not the available net capacity.

I completely would change my charging habit, if the BMS can automatically charge, when it needs to via wireless charging, but until then, no way, I fiddle around with a charging cable all the time...

 

[HerrCooles]

I won't get my Taycan until January. But I already know how I will behave. According to the study, a battery lasts the longest if it is operated between 40% and 70%. That's why charging will be geared towards my daily need for range. Should I plan a longer route, I can still charge it to 85% -100%. Fast charging only the go is no problem either.

 

[Taycanturbolondon]

I think if you look at the latest iPhones they all slow the charging rate dramatically as the SOC gets higher. Also they super slow as to fit the pattern at which you wake up (when overnight charging). I guess this gives battery longevity.

I intend to plug it into my slow 3pin socket every night. 95% of my driving is between 8-50miles per day with 16miles as the mode average

 

[Deleted member 1697]

according to what I can get from your thoughts :
fast DC charging on highway is acceptable ... but nobody will wait to 100%
slow AC charging by night before a tomorrow trip ... get 100% is acceptable
you don't have a trip tomorrow ? don't charge it
in summary, i don't mind ! OK ?
those who will get my 100,000miles Taycan in 5 years won't be happy ???

 

[Brassfactory]

according to what I can get from your thoughts :
fast DC charging on highway is acceptable ... but nobody will wait to 100%
slow AC charging by night before a tomorrow trip ... get 100% is acceptable
you don't have a trip tomorrow ? don't charge it
in summary, i don't mind ! OK ?
those who will get my 100,000miles Taycan in 5 years won't be happy ???

Right. I rarely fast charged my Tesla but did 100% charge it at home each night and after 4 years I could just barely notice some degradation. No problem.

But I find 85% on my Taycan is plenty of range so I’m following the recommendation. I’ll have a warm fuzzy feeling knowing it’s battery has degraded less.

 

[redrocket]

It depends:

if you are on a 2 or 3 year lease let it rip, charge to whatever you want

if you intend to keep the car for a longer term then stick with 85% or even a little lower if your driving habits can tolerate lower

I traded a MS LR for the Taycan, and the Tesla was almost exclusively charged at Tesla Superchargers. There’s one nearby and it was free charging. I only kept the car a year, but the battery showed zero degradation, and I usually let it charge to, or close to, 100%. I never intended to keep the car long term, although I thought I’d keep it longer than a year. But then I met the Taycan

 

[mike-taycan]

Charging it to 100% will shorten the life of the batteries but it’s debatable how much shorter it would be. As others have mentioned, all makers put in a buffer so you truly never get to the actual 100%. Tesla had an anticipated failure rate of their batteries and they are lasting way longer than modeled. I don’t think you will have the Taycan long enjoyable to require a battery replacement. But, I would stay away from 100% unless it’s required for your use.

 

[DennisB]

The tests above show us that with a 100% percent charge the battery degrades much faster, so Porsche advises us to use profiles etc to charge less percent. Right? But with the tests explained above they use the full 100% capacity of the battery. Porsche doesn’t use the full 100%, therefore we can never charge to 100% even if we want to. There is a margin build so we can only use for example 85% of the total capacity. And when in the future your battery degrades the 15% margin is used to convince you that your battery is stilll in good health.

When you charge your battery for 80% it’s actually 68% of the full battery capacity. So why do they recommend charging less than 100%? To expand the lifespan even more?

There is an article about this somewhere. I’ll try to find it.

 

[TAYC4S]

The tests above show us that with a 100% percent charge the battery degrades much faster, so Porsche advises us to use profiles etc to charge less percent. Right? But with the tests explained above they use the full 100% capacity of the battery. Porsche doesn’t use the full 100%, therefore we can never charge to 100% even if we want to. There is a margin build so we can only use for example 85% of the total capacity. And when in the future your battery degrades the 15% margin is used to convince you that your battery is stilll in good health.

When you charge your battery for 80% it’s actually 68% of the full battery capacity. So why do they recommend charging less than 100%? To expand the lifespan even more?

There is an article about this somewhere. I’ll try to find it.

Yes and this is interesting and would also explain why my Porsche dealer said I could charge to 100% all the time if I wanted to. As 100% is not the full battery capacity then it would explain why it’s ok to charge to that I guess.

 

[epirali]

Well this has been covered extensively before. Different chemistries and configurations push the cells differently. Some cars, like the I Pace, say charge to 100% always. The Taycan SPECIFICALLY says DO NOT charge to 100% unless you need to, use 85% max. So they believe if you do it when you don’t need it it will impact longevity.

When in doubt go with what is recommended by the manufacturer. Look in your manual.

Sponsored