another charging question

[IrwinJ]

I rarely drive more than 30 miles per day, and often far less than that. Question: is it okay to nightly put the charger on the car to top it off at 85%, or instead should I burn down the charge down to say 25% before putting it on the charger?

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[kort]

I rarely drive more than 30 miles per day, and often far less than that. Question: is it okay to nightly put the charger on the car to top it off at 85%, or instead should I burn down the charge down to say 25% before putting it on the charger?

if that what works for you there is no problem doing that.
I like to keep the car charged to 80%, the recommended level, all the time because I never know when a long ride will be needed to be taken and if I am at the low end of SOC it means an extra stop to charge.
so to sum up if you want to not charge the car until you are at a low SOC, that's fine.

 

[raharris]

I attended a Porsche day here in Ohio (they shipped in Taycans, 911s, Macan, Panameras for us to try out) that it was NOT a good idea to charge every day (same scenario for me as the original poster). I have not found anything else to ever support that, but this is what they shared.

As I have the flexibility, I let it drop to 35-40% and then top it up to 85% - it's actually more convenient this way as I don't have to plug/unplug each day. (Obviously, I'll top it up sooner if I need the range).

 

[kort]

I attended a Porsche day here in Ohio (they shipped in Taycans, 911s, Macan, Panameras for us to try out) that it was NOT a good idea to charge every day (same scenario for me as the original poster). I have not found anything else to ever support that, but this is what they shared.

As I have the flexibility, I let it drop to 35-40% and then top it up to 85% - it's actually more convenient this way as I don't have to plug/unplug each day. (Obviously, I'll top it up sooner if I need the range).

who is "they"?

 

[raharris]

who is "they"?

One of Taycan “experts” they brought along to answer questions.

 

[W1NGE]

I rarely drive more than 30 miles per day, and often far less than that. Question: is it okay to nightly put the charger on the car to top it off at 85%, or instead should I burn down the charge down to say 25% before putting it on the charger?

I would and do.

8 year warranty so what's to worry about?

 

[kort]

One of Taycan “experts” they brought along to answer questions.

experts? salesmen are far from being experts. from what I've seen from porsche is that there is a severe lack of expertise available at the dealership level.

 

[raharris]

experts? salesmen are far from being experts. from what I've seen from porsche is that there is a severe lack of expertise available at the dealership level.

They weren’t salesman; part of the team traveling with the cars from event to event. My bet is from marketing …. and I used quotes for a reason. As I said, not sure about validity of their statement, but my driving practices allow me to follow the suggestion with no impact to me; and is actually more convenient. If I hadn’t been unable to upgrade from 110v/12a charging I might have a different opinion

 

[W1NGE]

experts? salesmen are far from being experts. from what I've seen from porsche is that there is a severe lack of expertise available at the dealership level.

All Dealerships in UK (at least) have a 'Gold Technian' specifically trained in all things Taycan.

That said the collective knowledge and real world experience on this forum probably surpasses that.

 

[kort]

All Dealerships in UK (at least) have a 'Gold Technian' specifically trained in all things Taycan.

That said the collective knowledge and real world experience on this forum probably surpasses that.

that's great for you folks in the UK, here in my little part of the US that is not the situation.
my dealership has all of one certified taycan tech and it appears that he is not good at multitasking.

that said this is not a unique to porsche issue, outside of tesla, who's techs are obviously well versed in their product the level of EV specific knowledge of dealerships runs from abysmal to a bit above abysmal.

I have had a nissan dealership turn me away when I came in with a Leaf because they didn't have a trained tech who could work on the car, they used to send me coupons for oil changes, to porsche, where there is a lack of certified techs and then every repair appears to need approval from the mothership.

I just had my first encounter over at JLR because the onboard charger on my 2022 Ipace glitched and the car wouldn't charge, they offered me an appointment 5 weeks out.

great! an EV that cannot charge and they can't address it for weeks because they too lack the techs, and in the US JLR has sold only a handful of Ipaces. fortunately the problem cleared without any input from me.

knowledgeable folks on the forum is an asset, I am always taking info from here to my service advisor at porsche but that proves to be pointless because their response is "porsche hasn't approved this fix for your car", that was in response to inquiring about the latest recall.
so while armed with good info is good for people they sometimes run into the wall of bureaucracy at the service centers.

/ rant mode off

 

[daveo4EV]

technically speaking charing LiON batteries "less" will increase battery longevity - for daily driving scenarios (charging from like 47% to 85%) will it be detectable? probably not.

all LiON batteries have a certain number of charge cycles in their expected life-cycle - this is a fact - what is the number? anywhere from 1000 to 5000 depending on usage and exact chemical make up and other various SWAGS (SWAG = Scientific Wild Ass Guess) - how many cycles does any particluar battery have? only a few people inside Porsche corp. know - that's closely held confidential proprietary information - and varies widely among manufactures

given that the above statement is factual and "true" - charging "less" is good solid advice with regards to LiON battery chemistries

now here is the rub

the charge cycle "SWAG" is based on "full discharge and full charge" cycles - charging from 62% to 80% does not count as a "full" cycle - it counts as a partial cycle - how much impact do partial cycles have on a LiON battery? honestly factually truly _NO ONE_ knows - collectively we just know it's "less" impact than a full cycle (5% or less to 98% or more counts as a full cycle) - how much less? - again _NO ONE_ knows

exact impact on the battery's longevity for any given charge cycle from X% to Y% - you must be joking - we don't even have a SWAG for that!!! Honestly NO ONE knows…I'm not making this up. We can speak to LiON battery longevity based on broad truths and general impact and expected outcoming - the exact impact of any given action CAN NOT BE MEASURED with out destroying the battery and using electron microscopes to "assess the damage" to individual cells

now let's return to that "cycle" count (1000 to 5000 full cycles) - again a honest engineering SWAG…

not all full cycles are equal - other variables come into play…

temperature
voltage
charge rate (slow charging is better than fast charging)
time between charge cycles
beginning temp
end temp
how quickly was the battery discharged?
how "hard" was the battery discharged? (slowly or quickly)
long long the battery "sits" at any particular charge level
did you go down 15% and then let it sit - do it again - and then let it sit - and then charged it

the impact of any given "micro" action on your 93 kWh LiON Taycan battery _CAN NOT BE MEASURED_ - we can only speak in broad SWAGs about impact to your LiON battery - throw in manufacturing differences, battery design revisions, and individual cell characteristics and variations - well I hope you're beginning to see my point - no one actually knows what any specific action does in terms of impact to the battery's overall expected longevity - we just know less charging = more life - how much more - impossible to measure unless you're doing controlled full cycle testing and tracking _ALL_ the variables - and I mean _ALL_ the variables.

back agin to the cycle count - (1000 to 5000) expected cycles in the life of a LiON cell - how many cycles does Porsche expects for their batteries - they've told us - but only indirectly - 8 years or 100,000 milies - how many cycles is that - their answer outside the company would be "enough".

let's do some calendar math

charge the car on average 3.76 times a week over the course of a year (don't drive every day, and there are holidays when the car "sits" and is unused)
3.76 * 52 weeks a year = 195 charging cycles a year average usage case - let's call it 200 to make the math simple

_IF_ the expected cycle count is 1000 full cycles - then battery will last 5 years - this would still lead to an 8 year warranty - because no one expects those 200 cycles to be "full discharge/charge" cycles - they will be partial cycles

_IF_ the expected cycle count is 5000 full cycles - then expected life of the battery is 25 years if each of those charge cycles were "full cycles" - which they aren't - if they aren't full charge cycles then their impact on battery life is "less" - how much less? see SWAG complexity noted above…

therefore we can not talk about specific impact of any given action because we don't control all the variables - we can only talk in broad generalities about good vs. bad

• charging to less than full is better than charging to full
• charging at slower charge rates is better than faster charge rates
• charging fewer times is better than charging more times
• charging from 40% to 70% has less impact than charging from 5% to 98%
• temperature matters
• battery age matters
• previous discharge cycle "impact" matters

what is the impact of any given action? there is not even a SWAG for that - but there is a warranty.

charge the car when you need to
charge the car when you want to
don't over do it
but don't put yourself out with regards to managing the battery

there is nothing _YOU_ can do to the battery - this is true of all vehicle LiON batteries - there is sooooooo much software between you and the battery nothing you do will matter - Porsche's software manages the battery and it's charging - you don't - short of never driving the car…

about the only thing I would avoid is:

• fast charging multiple times a week (unless on a road trip)
• charging to 100% and then just leaving it there

at the end of the day the batterey gonna do what the battery's gonna do - and really honestly there is nothing you can do it about it. We don't even have a SWAG for that.

that actual cycle count of a given battery design & chemistry in the context of a production automobile is more of a legal/liability question than a scientific one. Because it only comes up in the context of how much warranty are we going to offer our customers? And warranty only kicks in after 30% "lost" capacity in the warranty period. So Porsche's warranty basically says we believe with the combination of our unique battery manufacturing techniques and battery management software and monitoring (voltage, temperature, kwh's in and out of the battery & rate of charge & discharge - which is all that _CAN_ be measured) that there is nothing _YOU_ as the consumer can do that will kill this battery in less than 8 years or 100,000 miles of usage. They came to that conclusions by polling their scientist and engineers and getting their SWAGs as to how is this thing going to behave? So Porsche is comfortable that their battery chemistry and assemmbly process and charging management software can't kill the battery in less than 8 years/100,000 miles in normal use.

what is normal use? well given 24 hours in the day. You can only discharge and charge 83.4 kWh at certain rates - so you can come up with a worse case daily cycle count at a worse case fast charge rate.

let's say you do your worst!! how many cycles a day could I do?

well 800V 270 kW fast charging - 3% to absolute 100% takes about 75 minutes - and I know I can discharge to 50% in 15 min on track at laguna - so 30 min to fully discharge - that's a total minimum cycle of 105 min - I can charge a Taycan in 75 min to 100%, and discharge it to 3% in another 30

24 hours = 1440 minutes in day
1440 min / 105 min min cycle (100% to 3% and back to 100%) = 13.74 cycles a day - let's call it 12 cycles due to some overhead

the most you can fully charge and discharge a Taycan's battery is 12 cycles a day in highest maximum demand situation

12 * 365 = 4380 cycle's annually
8 years * 4380 cycles = 35,040 cycles possible in an 8 year period

no LiOn battery is going to last 35,000 cycles - not gonna happen

good thing we have the 100,000 mile's clause in the warranty - cause we can do math on that also…

Taycan is about a 3.2 mile/kwh vehicle over the "long haul" - 100,000 / 3.2 = 31,250 kWh in/out of the battery to reach 100,000 miles

31,250 kwh / 84.3 kWh = 370 FULL charge cycles to reach 100,000 miles - or slightly more than charging every day for a year…

So porsche via what they tell us in their warranty is confident you can charge your car at least 370 times from 3% to 100% - because once you do that you've driven 100,000 miles or more - which is 31,250 kwh in/out of the battery to drive - if in those 31,250 kWh of consumption you battery loses 29% of it's total capacity - that battery is behaving "as expected and warrantied" - if your battery loses 31% of it's total capacity with in 31.250 kWh - Porsche is buying you a new/refurbished factory battery.

the real kicker here is the 31,250 kwh "limit" - that's kinda of the only "age" measurement we have - now that's the amount of kWh for ~100,000 miles - Porsche knows 10-20k miles a year is common - so that's 5-10 years to accumulate that many kWh's on the battery…which is in line with common expectations of longevity for major automobile components. And while replacing a battery is expensive for the consumer, it's no more or less expensive than replacing any major ICDE drive train component at 100,000 miles or more…

and we know Porsche is probably being conservative with their estimates/SWAGs…cause really honestly they don't want to have any warranties 'triggered" - so they are going to target better numbers in their battery design, goals, SWAGs - and they have a high degree of confidence only x% of batteries manufactured/used/managed-by-porsche-charging-software in the vehicle will ever "trigger" a warranty claim…

yeah - there is nothing _YOU_ can do to _YOUR_ battery - because between you and the battery is a whole bunch of Porsche software/hardware that is managing the battery's expected longevity so as not to trigger the warranty - and trust me this software knows all about cycle counts, charge rates, temperatures, and amount of power in/out of the battery - and that software's goal is to manage your battery so that doesn't "lose" more than 30% in less than 31,250 kWh…

100,000 miles is also worse case (3% to 100%) about 250 miles a charge (on average) - so 100,000 miles 3% to 100% @ 250 miles driving range per-charge is 400 full deep charge/discharge cycles - so Porsche expects their battery can handle at least 500 full charge/discharge cycles.

charge your EV when you want to - because there is nothing you can do to harm the battery - it's all being managed "for you" behind the scenes - and Porsche "knows" via SWAGs what the expectations are.

how long will your battery last? Somewhere between 500 to 35,000 charge cycles - 5,000 is an upper end - so let's call it 3000 to conservative. Charge your car 3.76 times a week on average - I think you can reasonably expect your battery to last:

500 / 3.76 = 132 weeks minimum 2.5 years - but 500 cycles times 250 miles per cycle = 125,000 miles
3000 / 3.76 = 797 weeks maximum 15.3 year - 3000 cycles times 250 miles per cycle = 750,00 miles

750,000 miles seems high - so the 3000 cycle count seems high

I'm going to SWAG - that 200,000 miles is the outside limit before you'll want to replace a Taycan battery - by then you should've clearly lost 30% or more capacity - 200,000 miles / 250 miles per charge = 800 full charge cycles - or 200,000 miles / 3.2 miles/kWh = 62,500 kWh

I'm gonna bet Porsche SWAG's their battery cycle count somewhere between 1000-1500 expected cycles - that would give them enough confidence to warranty them for 8 years/100,000 miles with a healthy margin that if their SWAGs are on the money - they should not have a lot of warranty claims.

how often should you charge your car?

well long is it going to take to reach 1250 charging cycles based on what you're doing? Cause I'd say that's a pretty good SWAG at what we're looking at in terms of battery life.

1000-2000 full charge cycles is common and expected in the industry for current LiON battery chemistries and SWAG'd battery management policies - I doubt Porsche has a battery chemistry that is expected to do much better than 2000 cycles - 1500 would be my guess as to their internal design goals - the real key here is that about 30,000 kwh's in/out of the battery is about 100,000 miles - so again I'm going to swag that Porsche believes they can managed 40,0000 kWh's in/out of the battery at most any charge rate and not lose more than 30% total capacity…

amount of kWh's in/out of a LiON battery is much more important than milage/odometer for an EV - and is the main measure of a battery's age. hmmmm Porsche doesn't give us that data - wonder why?

this would be "akin" to "over-revs" for manual transmission Porsche's when buying a used EV…I'd think we as consumers should have access to that - because I doubt _ANY_ one's LiON battery chemsitry is rated for much more than 50,000 kWh's (Elon's talking 1,000,000 mile batteries as a "goal" - at 4 mile/kWh that's 250,000 kWh in/out of a battery to drive 1,000,000 miles)

so 20,000 kWh is "low"end easy peasy battery longevity goal
250,000 kwh is high-end unubtainiuum pie in the sky limits of current bettary tech - nothing in production…

I'm going to bet the industry SWAGs their batteries at 30,000 to 50,000 kWh's usable life span - after that all bets are off - but your battery will be well outside the warranty by that point - so then it's on you if you want another battery to take another bit of the apple for another 30,000 to 50,000 kWh's.

 

[daveo4EV]

oh and dealerships are clueless with regards to ICE vehicles with 10's of years experience
dealers with regards to EV's - don't make me laugh - they KNOW NOTHING!! To expect otherwise is simply naive…

and in public anything they say is liable and actionable in future actions against the company - so they are going to be very conservative.

Tell a customer to not charge the car ever day is very conservative. And unlikely to make things worse - so yeah we can tell the customer that.

But they certainly are not going to tell the customer to fast charge from 3% to 100% 12 times a day -cause yeah - that will probably trigger the warranty.

 

[IrwinJ]

oh and dealerships are clueless with regards to ICE vehicles with 10's of years experience
dealers with regards to EV's - don't make me laugh - they KNOW NOTHING!! To expect otherwise is simply naive…

and in public anything they say is liable and actionable in future actions against the company - so they are going to be very conservative.

Tell a customer to not charge the car ever day is very conservative. And unlikely to make things worse - so yeah we can tell the customer that.

But they certainly are not going to tell the customer to fast charge from 3% to 100% 12 times a day -cause yeah - that will probably trigger the warranty.

just to confirm, the fast charging you refer to which could cause a problem is the level 3 DC charging, yes? But level 2 charging at home isn’t a problem, right?

 

[daveo4EV]

just to confirm, the fast charging you refer to which could cause a problem is the level 3 DC charging, yes? But level 2 charging at home isn’t a problem, right?

yes DC Fast chargers are the "hardest" on LiON batteries - but charge rate also matters - some fastDC chargers are 25 kW - other's are 350 kW (270 is Taycan max)
Home chargers max out at 19.2 kW - but unless you optioned the 19.2 kW charging option, your Taycan is 11 kW max at home
if you're using the Porsche PMC+/PMCC on a NEMA 14-50/6-50 plug you're charging at 9.6 kW

in the game of SWAG's 9.6 kW charging (PMC+/PMCC) is almost inconsequential vs. 270 kW charging in terms of impact

the general rule is slower charging is better - and _ANY_ home charging setup is consider slow on the scale we're talking about.

 

[IrwinJ]

yes DC Fast chargers are the "hardest" on LiON batteries - but charge rate also matters - some fastDC chargers are 25 kW - other's are 350 kW (270 is Taycan max)
Home chargers max out at 19.2 kW - but unless you optioned the 19.2 kW charging option, your Taycan is 11 kW max at home
if you're using the Porsche PMC+/PMCC on a NEMA 14-50/6-50 plug you're charging at 9.6 kW

in the game of SWAG's 9.6 kW charging (PMC+/PMCC) is almost inconsequential vs. 270 kW charging in terms of impact

the general rule is slower charging is better - and _ANY_ home charging setup is consider slow on the scale we're talking about.

thanks, and yes I’m charging at 9.6 kW using my PMCC at home on a NEMA 14-50 outlet connected to dedicated 50 amp breaker. so basically, I can choose to top off to 85% at any time, whether I’m down to 25% charge or 60% charge, it’s all the same?

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