Why is 85% battery recommended as the normal maximum?

[svp6]

on the Turbo S the mileage is pretty low so it does become an annoyance since you reduce an already low mileage by another 15%..........

Is the range of the Turbo S low because drivers are more likely to go a tad faster ? I am not naming names.....

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[feye]

Weird for me to plug in when I have "only" 70% and don't plan much driving the next day, but I do it anyway and just have no worries.

Everybody has different use case and habits. I don't charge, if I don't need it.

 

[feye]

This keeps coming back. Again, only Porsche knows what buffer they have and how that is split top / bottom. As I showed before, regen is much more wimpy at 100% than at 85%, which suggests there is little buffer at the top - if any at all.

Yes, I was told this, when I test drove it at the Hockenheimring. But then there is no harm in using the disk breaks once in a while, is there?

How do you come to the conclusion, that there is no buffer at the top to protect the battery?

 

[svp6]

Yes, I was told this, when I test drove it at the Hockenheimring. But then there is no harm in using the disk breaks once in a while, is there?

How do you come to the conclusion, that there is no buffer at the top to protect the battery?

Several things:
1. Available energy is larger than the initially reported 83.7 KWh. This must come from somewhere - and while I do not have any direct proof, I would guess most of it came from abandoning (at least in part) the top buffer.
2. Charging speed tapers considerably at the top - although not as brutal as in Tesla.
3. Reduced regeneration means less battery available for charging.

The reason I commented about the wimpy regen at 100% is not because I worry about using the disk brakes, but because it demonstrates the reduced / absent buffer at that state of charge.

 

[PanameraFrank]

The reason I commented about the wimpy regen at 100% is not because I worry about using the disk brakes, but because it demonstrates the reduced / absent buffer at that state of charge.

This is inaccurate. You wouldn't design a buffer that allowed regen to bypass it. You'd software limit all charging and regen to the non-buffered capacity, which is the entire point.

The iPace has a confirmed buffer at the top (you cannot reach true 100% charge, confirmed by JLR, and the buffer at the top was at least 2 kWh from testing, likely more) but doesn't have regen at 100% and has reduced regen until you hit 90%, due to software limiting.

I don't know how much buffer the Taycan has on the top & bottom, I've yet to see an official number, but your reasoning on the regen doesn't hold up or prove anything.

 

[svp6]

This is inaccurate. You wouldn't design a buffer that allowed regen to bypass it. You'd software limit all charging and regen to the non-buffered capacity, which is the entire point.

The iPace has a confirmed buffer at the top (you cannot reach true 100% charge, confirmed by JLR, and the buffer at the top was at least 2 kWh from testing, likely more) but doesn't have regen at 100% and has reduced regen until you hit 90%, due to software limiting.

I don't know how much buffer the Taycan has on the top & bottom, I've yet to see an official number, but your reasoning on the regen doesn't hold up or prove anything.

You may be correct - as I said, only Porsche knows for a fact. Let's do some math though. First, theoretically available energy assuming 93.4 kWh total. The model S batteries have a reported bottom buffer of 2.5-4 KWh, the model 3/model Y batteries a 2.5 kWh bottom buffer. Let's assume Porsche has similar bottom buffers (2-4), and that gives us the following available energy at 0 /2 /4 /6 /8 kWh top battery buffer:

So range of total available is 81.4-89.7 (4 kWh bottom buffer) or 83.4-91.7 kWh (2 kWh bottom buffer).

Now let's take my previously posted consumption data on several medium distance trips. I calculate the energy used by multiplying the distance by Wh/ mile, then infer total available energy corresponding to 100% from that.

As you see, the average estimated available energy is 91.5 kWh. Now of course there are errors:
1. The odometer distance may be inaccurate. This is definitely true, but minor. I plotted on Google maps the routes and the distance was within 1 mile of the odometer. So less than1%
2. The reported Wh/mi is wrong. This can be the case, but there is no way for me to verify that. I would presume though errors should not be too large, probably within the same <1%.
3. Battery size is not precisely 93.4 kWh. This is quite likely the case (averages, imprecision in estimating battery size, etc.). Perhaps I am the lucky recipient of a 95 or 96 kWh battery - which renders all the calculations wrong. But if I assume I am just an average Joe, size should not be that far from 93.4.

I did look how much energy the wall charger delivered to replenish the battery (to 85% ) after the last trip (bottom row). It delivered ~13.4% more energy than the one used, which is in line with what I would expect from charging losses - but also indirectly supporting the used energy reported by the PCM.

So after all these exercises, you tell me how much buffer you think we have at the top given all these. My best guess is very little - close to 0.

 

[feye]

Several things:
1. Available energy is larger than the initially reported 83.7 KWh. This must come from somewhere - and while I do not have any direct proof, I would guess most of it came from abandoning (at least in part) the top buffer.

How do we know the exact gross capacity of the pack? Porsche is known to under report and you say it did so on the net capacity, how do we know it did not so on the gross?

2. Charging speed tapers considerably at the top - although not as brutal as in Tesla.

Could indicate that there is plenty of buffer on the top. This would even make sense, because most of the time, EVs are not driven to below 5%, but often charged to 100%. So stats wise, there could be a case made that the buffer on top is more important than on the bottom.

3. Reduced regeneration means less battery available for charging.

The reason I commented about the wimpy regen at 100% is not because I worry about using the disk brakes, but because it demonstrates the reduced / absent buffer at that state of charge.

Or it could simply mean that the battery management system in the car does maintain the buffer to protect the battery and keep it operational for many launch controls to come.

Do I sense too much t thinking and too little faith in German engineering?

 

[feye]

You may be correct - as I said, only Porsche knows for a fact. Let's do some math So after all these exercises, you tell me how much buffer you think we have at the top given all these. My best guess is very little - close to 0.

Interesting and nice presentation, but the guess work relies on the actual gross capacity, which nobody knows.

 

[felixtb]

Is the range of the Turbo S low because drivers are more likely to go a tad faster ? I am not naming names.....

You might be on to something.... I keep mine at 90% I'm sure the Porsche batteries are as reliable as the Tesla ones..... LG Chem or Panasonic..... its a toss-up

 

[svp6]

Interesting and nice presentation, but the guess work relies on the actual gross capacity, which nobody knows.

Straight from the horse's mouth.... But feel free to believe Porsche actually puts much larger battery packs without advertising to allow for the mythical large buffer at the top

 

[DragonRR]

This keeps coming back. Again, only Porsche knows what buffer they have and how that is split top / bottom. As I showed before, regen is much more wimpy at 100% than at 85%, which suggests there is little buffer at the top - if any at all.

Here is why I only charge to 85%
1. Battery degradation is faster when charging to 100%, especially if your battery stays fully charged for some time.
2. As you well know, the Porsche connect app keeps track of your charging history. I would seriously doubt that Porsche will care one bit about complaints of range loss if they can show you charged to 100% frequently. Why should they cover the repair / replacement if you specifically did not follow the recommendation and they can easily prove it? So use it at your own risk - if you are as unlucky as some of the infamous Tesla 90D owners who lost substantial battery range in short time, good luck complaining.
3. I do not miss at all the top 15% for daily commute.
4. If I travel next day, I have a "travel" profile that charges to 100% so I use that instead of 85%.
5. If I forget to charge to 100% the night before the trip (happened to me), I will spend almost 5 more minutes at the fast charger to catch up.

In short, the only 2 circumstances where I think you absolutely must have 100% charge are super-long commutes or trips where you need those extra miles to make it to the charger.

As Felix said it matters more to Turbo S owners because the range is already reduced. Also.. in the UK fast chargers are pretty damned rare! I think there are currently only 3 or 4.

That's an interesting graph! As far as whether it is acceptable to void a warranty because you haven't followed some recommendations is debatable. As mentioned in my post there must be some reasonable limit on battery degradation even with fast charging and 100%. My dealer didn't mention the 85% charge at all although their demo was always charged to 85% so someone there knew about it.

The Turbo S has a larger front motor I understand. I presume this along with - maybe the filled in gills and wider tyres? makes it have a lower range even when driven carefully.

@feye Whilst it may be true that there is a sizeable top buffer it is very unlikely based on current information available. I would agree with svp6 - there is little to no top buffer and charging to 100% will reduce battery life as the manual makes clear.

 

[Scandinavian]

My dealer didn't mention the 85% charge at all although their demo was always charged to 85% so someone there knew about it.

I think owners on this forum know more about Taycan than the dealers. My dealer even tried to convince me that the Olea leather option was a vegan option! I guess the dealers will learn about the cars but it also takes a level of interest to really ge5 to know these EV”s

 

[svp6]

The Turbo S has a larger front motor I understand. I presume this along with - maybe the filled in gills and wider tyres? makes it have a lower range even when driven carefully.

Nah, I was just trolling @felixtb. Of course the range is lower in the turbo S, but not by much - reported 300 miles at 70 mph in US, 250 miles at 80 mph in Germany (both on Youtube). But if you keep your car in Sport mode (I do that) you will come a little short of those numbers.....

 

[felixtb]

Nah, I was just trolling @felixtb. Of course the range is lower in the turbo S, but not by much - reported 300 miles at 70 mph in US, 250 miles at 80 mph in Germany (both on Youtube). But if you keep your car in Sport mode (I do that) you will come a little short of those numbers.....

300 miles for a TS.......? the highest I have so far is 240......... and that's really being calm................

 

[DragonRR]

Yes, that's all I got too Felix. Also, in a Turbo in Range mode for half of the trip I got about 200 based on remaining battery percentage.

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