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tigerbalm

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whitex

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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)…
Did anyone do a CAN bus scan when battery shows 100%, if so what are the cell voltages? Taycan cell nominal voltage is 3.65V, which would suggest that its 100% voltage would be 4.2V.
 

whitex

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It would be implemented as a negative current limit in the inverter control and would adjust based on capacity.
It's adjusted based on a lot more things than just current SoC. Other factors that I'm sure are considered is current battery temperature, battery age, battery history, motor and inverter temps, probably other factors too.
 

Jhenson29

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It's adjusted based on a lot more things than just current SoC. Other factors that I'm sure are considered is current battery temperature, battery age, battery history, motor and inverter temps, probably other factors too.
Yes, I’m sure there are other factors. I was just commenting on limiting based on capacity.
 


B61

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yes - but unless we know "where" the buffer's are in the 93.4 kWh - most are at the bottom and less is at the "top" of the battery range...so we don't know how stressful 100% actually is on the battery - because Porsche has not disclosed the "hold back" amounts and what the split is between the bottom and top range buffers…
But still: if 100% is stressful/problematic, why they are not using software, to prevent that?
 

whitex

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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%.



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.
A decade of driving Model S's. Always charged to 90% every time in the garage (regardless of SoC when coming to the garage), 98% for longer trips (don't like 100% because it disabled regen, makes the car drive different) - minimal battery degradation on all 4 of my Model S, the oldest being 7.5 years old. Plan to do the same to the Taycan, maybe 85% instead of 90% if that is what Porsche UI suggests as upper daily range (UI should always be more up to date than any user manuals). Keeping it plugged in just makes sense as it gives the car a choice to charge or use shore power if it needs to.
 
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whitex

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If fast charging is not recommended, why would they give you access to Electrify America and they’re fast chargers where you can get 30 minutes every day to charge your battery?
Fast charging does degrade the battery, that is a fact. There is a rumored spare capacity in the Taycan batteries (it charges to lower SoC at first, will try to confirm one Porsche manages to build and deliver one for me). Why would they let you? Because you need it on long distance trips. Does it degrade the battery faster? Sure it does, as does using launch control mode. Does Porsche still warranty the battery even if you charge at 250KW and lanuch every day? Of course they do, but notice that they don't guarantee 100% of the original capacity. I have not found the actual percentage, but Tesla for example only warranties 70% of original capacity in 8 year or 100K miles. So if a 400 mile range Tesla degrade 280miles, it's still not covered under warranty (279 qualifies you for warranty coverage). I suspect Taycan is the same.

I have a level 2 48A at home and I can regulate the amperage on it. Should I bring it down to 40 would that really make a difference?
11KW is not fast charging. Minimum DC charging is 50KW, and the charging rate which starts to do damage is usually considered 1C (i.e. rate which would charge the battery in 1hr), so for a Taycan, ~97KW. As a side note, I've been charging one of my Model S at 80A and another at 48A for years, minimal degradation.

im going to stay with the 85% cap unless need to do a long trip, I want to see data before going the extra 15%
That is my plan once the Taycan gets here (current TYD estimate February 2023). For trips I plan to do 98% since that keeps regen enabled, unless it's winter then 100% on trips since regen is limited by low temps of the battery anyways.
 
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whitex

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My first sales advisor told me something similar; "if you're not going to keep the car more than 3 years just charge to 100% every day."

I found that kinda selfish, and opted to charge to 85% anyway matching the manual's recommendation.
Honestly, who cares. You can ask for battery health when buying used, or just scan it yourself using a $50 worth of hardware and apps. Warranty still applies regardless if you keep it at 50% and never drive it, or you drive is 90K miles and charge to 100% using DC charging every day. On a Tesla rated range at 100% is a good indicator, not sure if there is an equivalent on a Taycan, but you can scan it using CAN bus (which you can do on Tesla but it's more complicated than just plugging in an adapter to OBDII port).
 
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whitex

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yep I was wrong - post updated - I'm sure the BMS will also penalize me.
Oh no Dave! ? How could you not triple check whether your post was correct (prime numbers under a 100 are super google'able)? :pCudos for correcting it. ?
 

whitex

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Mid-grade charge is with PMC+/PMCC - the electrons have 1/2 the energy - you have to charge with ClipperCreek, Wallbox, Tesla, ChargePoint to get "full power" high-octane electrons

Porsche halve's their electron energy in the north american EVSE market to avoid battery stress and EVSE overheating…

* - yes I'm kidding!!!!!
Rubbish! Only Porsche EVSE's pre-condition the electrons to be ideally aligned in orientation and spin to provide the lowest battery degradation, smoothest and most optimal power delivery! :CWL:
 

johnarpy

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Petrol / diesel anology doesn't really work with batteries unfortunately.
The point is the car is advertised and sold with a stated range at 100%. A petrol car is also sold with a stated range calculated by tank size. If an electric car should only be charged to 80%, then that should be the advertised range.
 
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Tooney

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Keeping it plugged in just makes sense as it gives the car a choice to charge or use shore power if it needs to.
Could you elaborate on the point about keeping it plugged in? Is that an EV manufacturer's recommendation? Thanks.
 

W1NGE

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The point is the car is advertised and sold with a stated range at 100%. A petrol car is also sold with a stated range calculated by tank size. If an electric car should only be charged to 80%, then that should be the advertised range.
I don't think the state of fullness (or emptiness) is actually mentioned - we are simply given a fairly fictitious WLTP figure for range which none of us can match.

Besides, the EV mentality is only to charge to what you actually need for that day rather than always strive to have a full tank. This approach helps enormously with range anxiety.
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