OK to full charge to 100% regularly?

[TAYC4S]

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.

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[daveo4EV]

I would trust exactly zero (0%) information from a dealer - dealers have iffy information regarding ICE’s - their experience and wisdom regarding EV’s is often laughably wrong - EV wisdom of the crowd - don’t charge to 100% unless you need to…

100% is 83.4 kwh - 85% is 70 kwh - a different of about 13 kWh - at 3 miles/kwh average range that’s a difference daily of 40 miles range - unless you need the 40 miles on a daily basis it really isn’t going to hash your buzz to only be charged to 85%…

I’d stick with Porsche engineering’s recomendations which they bothered to print and research in the manual.

 

[Deleted member 1697]

how long is the warranty on the battery again ?
how can they tell you "damn, you've charged it to 100% ! now it's over, buy a new one!"

don't mind
some of us will be telling what the f... the car make approaching 99.9% of the battery .... BOOOUUU

 

[daveo4EV]

there is a warranty but Porsche has built in a pretty heft % battery is allowed to degrade before warranty kicks in - so the issue is how much do you want to lose top end capacity in order to have 40 miles more range "in the tank" on a daily basis…especially given that you are highly unlikely to tap that range on a daily/weekly basis…

it is however a long term issue not a short or medium term issue for the vehicle, it is however an issue for the 2nd, 3rd and 4th owner of the vehicle.

 

[Brassfactory]

Fast charging and full charging degrade battery life. The warranty isn’t voided by full charging. However, the amount of expected degradation allows for it.

The worst that will happen is that in several years your battery will charge a lower amount, passing even the buffer and delivering a lower range. If that’s ok with you, charge away.

 

[Schlossj]

And as discussed a million times elsewhere, is the only way to really plug and run without charging going to 100% every time is 1) set profile to 25% min and preferred charge times (say 12am-7am) and 2) set timer to target charge of 85% and departure timer of 7am? Plug in whenever you want and it will wait to "top off to 85%" after 12am and will stop at 85%? AND all of this app setting / profile and timer usage won't trigger the dreaded 12V dead batter issue...OR - just plug in and charge once you're in for the night and have Siri set an alarm for essentially ~1% every 6 minutes @ a 10kW charge rate?

 

[TAYC4S]

And as discussed a million times elsewhere, is the only way to really plug and run without charging going to 100% every time is 1) set profile to 25% min and preferred charge times (say 12am-7am) and 2) set timer to target charge of 85% and departure timer of 7am? Plug in whenever you want and it will wait to "top off to 85%" after 12am and will stop at 85%? AND all of this app setting / profile and timer usage won't trigger the dreaded 12V dead batter issue...OR - just plug in and charge once you're in for the night and have Siri set an alarm for essentially ~1% every 6 minutes @ a 10kW charge rate?

Thanks but I have not so far experienced any need for this over-engineered solution. I set (in the all) the 85% charge to be ready by certain time, and the car is there all waiting and prep’d to go. It even waits to start the charging process so that it’s completed on time.

 

[Neptune]

The main issues with batteries in general not just ev's, is keeping a battery charged at 100% and not using it.

Having the battery hold 100% charge for long periods of time is what causes battery degradation. If you charge to 100% and start using it immediately then the wear on the battery is significantly reduced.

For Example (worst case)

If you get home and start charging your car at 6PM and it reaches 100% charge by lets say 11PM, it will hold 100% charge for 9 hours if you use the car by 8AM the next day.

That roughly equals 136 days that the battery is holding 100% charge and not being used during the course of a year. This is specifically what causes battery degradation.

Personally I think you can hold 100% charge (not in one go) for about 20 to 30 days out of the year without it causing a noticeable degradation in battery capacity.

 

[feye]

So quick question. The general consensus seems to be, charge to 85% unless doing a long run in which case charge to 100%.

I did not set a Timer nor a Profile and just charge the car to 100% over night. I then drive it down to 1-4% and then charge it to 100% again. So 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!

The battery should easily be able to handle 2000 cycles without a significant degradation if operated in reasonable temperature and charging speed. Both is the case for me.

Operating the car this way feels like driving an ICE with a gas station at home but without the stink! Perfect!

 

[feye]

The main issues with batteries in general not just ev's, is keeping a battery charged at 100% and not using it.

Having the battery hold 100% charge for long periods of time is what causes battery degradation. If you charge to 100% and start using it immediately then the wear on the battery is significantly reduced.

For Example (worst case)

If you get home and start charging your car at 6PM and it reaches 100% charge by lets say 11PM, it will hold 100% charge for 9 hours if you use the car by 8AM the next day.

That roughly equals 136 days that the battery is holding 100% charge and not being used during the course of a year. This is specifically what causes battery degradation.

Personally I think you can hold 100% charge (not in one go) for about 20 to 30 days out of the year without it causing a noticeable degradation in battery capacity.

Do you have any data for this?

The only complaint we know so far is somebody using IONITY a lot. His battery got very hot in the process with significant degradation.

A German YTer says the key to keep range is to charge it slowly.

 

[Neptune]

Do you have any data for this?

The only complaint we know so far is somebody using IONITY a lot. His battery got very hot in the process with significant degradation.

A German YTer says the key to keep range is to charge it slowly.

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.

 

[jheard]

The main issues with batteries in general not just ev's, is keeping a battery charged at 100% and not using it.

Having the battery hold 100% charge for long periods of time is what causes battery degradation. If you charge to 100% and start using it immediately then the wear on the battery is significantly reduced.

For Example (worst case)

If you get home and start charging your car at 6PM and it reaches 100% charge by lets say 11PM, it will hold 100% charge for 9 hours if you use the car by 8AM the next day.

That roughly equals 136 days that the battery is holding 100% charge and not being used during the course of a year. This is specifically what causes battery degradation.

Personally I think you can hold 100% charge (not in one go) for about 20 to 30 days out of the year without it causing a noticeable degradation in battery capacity.

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.

FWIW I have run a Tesla for over 3 years and rarely charged to 100% maybe 6 times year at most and had same battery degradation as others who had charged to 100% on rapids several times a week. About 10% of range I lost in 2 years then it levelled out and stayed the same for the last 18 months. As others have said things like daily fast charging and charging to 100% and leaving it there isn’t good for battery health longer term but AC charging at home 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

 

[TAYC4S]

FWIW I have run a Tesla for over 3 years and rarely charged to 100% maybe 6 times year at most and had same battery degradation as others who had charged to 100% on rapids several times a week. About 10% of range I lost in 2 years then it levelled out and stayed the same for the last 18 months. As others have said things like daily fast charging and charging to 100% and leaving it there isn’t good for battery health longer term but AC charging at home 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

Thanks appreciate the reply and I like the advise!

 

[Scotty]

Like others have stated dealers in my area ( los angeles) are clueless re the technology of the car. I set general profile to 85 percent charge. Based on my research if you want the battery's life to be optimized charge to 85 percent unless your planning a long trip. Btw on a full charge i am getting a range of 300 miles plus

 

[NC_Taycan]

The facts about Li-Ion chemistry are well known, and have already been covered in this thread. More frequent fast charging and more time spent charging to and holding charge above 90% degrade the battery chemistry. I don't think that's the discussion point here though. If you don't plan to keep the car a long time (more appropriately don't plan to put a large number of miles/KMs on the car) AND you don't care about the value to whomever gets the car after you, then charge however you want - it's not likely to matter to you. Porsche may be able to turn on diagnostics about how a battery was treated over its life to support the used Taycan market but unless such efforts could be demonstrated to enhance brand loyalty or new car sales, I don't see them actually doing this. Tesla did not do this.

I put almost 100K miles on a 2012 Tesla Model S P85. Rarely charged to 100% (but did not hesitate to do so if I thought I might need it - probably ten times a year), 80% the rest of the time. 100% range when new - 265 miles. Range when sold - 245 miles. So taking care of the battery is helpful, based on a sample size of 1.

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