Dealer advised charging to 100% always

[BLH]

Picked up my new Macan EV rwd
During the handover the dealer recommended always to change to 100% on your home charger. AC. I said this contradicts what I've read about the 80% across manufacturer rule. He said that is old thought methods and porsche now recommend charging to 100%. Only charge to 80% when leaving the car in an unused state for a period of time (unclear on what that time frame was)
When I asked why, he replied the science now was that the 20% left unused cells were consistently not being used/charged regularly therefore the cells would likely deteriorate more overtime.

anyone else has this advice?

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[SergeyIndy]

Complete and total nonsense, so let's agree not to listen to clueless dealers, that is the advice.. If they say, corporate told them, then let's see some proof. I have access to internal docs and the chemistry while improved did not change the fundamentals of battery care from Taycan. I can share tons of data and studies.

In short if you want to follow best practices then charging to 80% for daily use still stands as a general recommendation, charging to 100% only when you plan to use it asap, and keeping the car at 50% when at rest for long periods, and do not keep car at 25% or less for long periods. However, there is a camp that would say that there is nothing you can do to harm the battery so you can do whatever you want and BMS will handle it. I choose to follow best practices.

Quick look at the manual for 2026 that dealers do not read, so please print, and put that in front of their faces:

 

[BLH]

Complete and total nonsense, so let's agree not to listen to clueless dealers, that is the advice.. If they say, corporate told them, then let's see some proof. I have access to internal docs and the chemistry while improved did not change the fundamentals of battery care from Taycan. I can share tons of data and studies.

In short if you want to follow best practices then charging to 80% for daily use still stands as a general recommendation, charging to 100% only when you plan to use it asap, and keeping the car at 50% when at rest for long periods, and do not keep car at 25% or less for long periods. However, there is a camp that would say that there is nothing you can do to harm the battery so you can do whatever you want and BMS will handle it. I choose to follow best practices.

Quick look at the manual for 2026 that dealers do not read, so please print, and put that in front of their faces:

Figured that was the case. First EV. Dealer nonsense.

 

[Somehow]

In general this depends on the battery's chemistry / architecture. There are some battery types which should better be charged to 100%, but to my knowledge that's not the case with the Macan. But I don't really know much about the Macan's battery.

 

[SergeyIndy]

In general this depends on the battery's chemistry / architecture. There are some battery types which should better be charged to 100%, but to my knowledge that's not the case with the Macan. But I don't really know much about the Macan's battery.

And you would be correct, 100% recommendation applies to LFP (Lithium Iron Phosphate) EV batteries. Macan EV battery is a common NMC type that is not recommended to be charged to 100%, specifically NMC 811–class chemistry (high‑nickel NMC) the same family used in the Taycan and Audi PPE‑platform EVs.

 

[craz8]

If Porsche had discovered a way for their HV batteries to allow the full 100% charge at all times without risking physical harm, there would have been a major breakthrough in battery physics and chemistry, and that's a very big deal. There would have been at least a press release!

Porsche did NOT do that, and your dealer is mistaken.

Hopefully this is from the dealer's sales team, and not from someone in the service department, as you need those people to know the reality of the cars their working on.

Occasional LFP charging to 100% is required for software calibration, but you should still not keep it there for a long time, as the same physics and chemistry principals apply. Solid State batteries allow better management of the physics to reduce problems at high charge, which is why there's so much effort going into their development.

The original description implies that the dealer seems to think that at 80% charge, 80% of the cells are charged fully, and 20% are entirely empty. This is not how batteries have ever worked - the Battery Management System works quite hard to keep ALL the cells at 80% in this example, by adjusting the amount of power stored in each cell. With Lithium batteries, an empty cell is a permanently damaged cell.

 

[W1NGE]

Picked up my new Macan EV rwd
During the handover the dealer recommended always to change to 100% on your home charger. AC. I said this contradicts what I've read about the 80% across manufacturer rule. He said that is old thought methods and porsche now recommend charging to 100%. Only charge to 80% when leaving the car in an unused state for a period of time (unclear on what that time frame was)
When I asked why, he replied the science now was that the 20% left unused cells were consistently not being used/charged regularly therefore the cells would likely deteriorate more overtime.

anyone else has this advice?

Bollocks!

See attached from MY26 Owner's Manual.

100% is fine if using the car on a given day e.g. for a long journey.

 

[craz8]

Here's a short technical video that covers why storing at high temp and SOC are 'bad', and why charging to 100% all the time is not recommended for the ultimate longevity of the battery. He links to another of his about how Lithium batteries work in general too!

Since ours are NMC 811, the final part about 75% max regular charge applies here, and I've been keeping to 75% if I don't need a full charge (although the ~5kwh built in buffer between net and gross storage may allow for 80% charge to not get into that plateau stage)

 

[ColdCase]

How much is the degradation over 10 10,000 mile years?

There are some recent EVs where you can't limit charging to 80% using the car GUI (or app). These cars, have to be limited from the EVSE or via clever scheduling. The school of thought there is that 80% is much to do about nothing to the typical driver. Perhaps different battery tech.

Perhaps the 80% is there for those EV manufactures that maximize range for advertising purposes at all expense of durability/safety risk. Where others add more margin and sacrifice a bit of range to protect ourselves from ourselves.

Anyway Porsche wants us to limit to 80% for their batteries. I don't think anyone really makes public the implications over a 10 year life of 100% charge. A 100% charge is more cell voltage then a 80% charge, however. Higher voltages may find defects/leak, heat up the battery, and cause a nasty fire.... bad publicity.

It is a conspiracy

 

[Wivenhoe]

Simple question to the salesman - if he is right about 100% why does the My Porsche suggest you select optimised charging which it to 80%. If thinking has changed they would change the limit imposed by ‘optimised’ charging.

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