Optimising Battery Health: Topping Up to 85% vs. Draining to 25% Before Recharging

[peterjames]

I have a question regarding charging: Would it be better to keep the battery topped up to 85%, or should I let it drain to around 25% before recharging to 85%? What approach would be optimal for maintaining battery health?

Thanks

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[M_Taycan_Turbo]

Operating between 70% and 45% for the majority of the time is ideal.
Store at 30% when going away for long times in summer.
Eliminate oxygen release from high Ni materials - stay below 75% SOC when you can
Eliminate the large volume change in high Ni materials - stay below 75% SOC when you can

 

[Scandinavian]

I have a question regarding charging: Would it be better to keep the battery topped up to 85%, or should I let it drain to around 25% before recharging to 85%? What approach would be optimal for maintaining battery health?

Thanks

You may find this video in the first post here useful. Video by Jeff Dahn

https://www.taycanforum.com/forum/threads/baseline-for-hv-battery-soh-performance.12815/

 

[W1NGE]

I have a question regarding charging: Would it be better to keep the battery topped up to 85%, or should I let it drain to around 25% before recharging to 85%? What approach would be optimal for maintaining battery health?

Thanks

Not sure there's a concern here especially if predominantly AC charging.

I wouldn't sweat it basically - do what you need to do as and when. You have an eight year 100K miles battery warranty.

Daily ultra fast DC charging at 200kW plus would be much more impactful. Same warranty however.

 

[Scandinavian]

Daily ultra fast DC charging at 200kW plus would be much more impactful. Same warranty however.

Interesting enough, in the video Jeff Dahn mentions that charging speed does not impact much. It seems high temperatures are the main issue for modern batteries and BMS.

 

[Vim Schrotnock]

I'm a believer that actual data on the specific car is better than general 'expert' recommendations. I have been charging pretty much every day for 3-1/2 years to 85%, and my range has not decreased at all and my OBD SOH is 94%. Additionally, I spoke with one of the 11 certified Porsche battery technicians, and he said 85% every day is perfect. He did recommend that I drain the battery down to 10-15% once every few months, and let it sit overnight and then recharge to 100% - something we are calling 'battery rebalancing'.

 

[peterjames]

Thanks. Just curi

I'm a believer that actual data on the specific car is better than general 'expert' recommendations. I have been charging pretty much every day for 3-1/2 years to 85%, and my range has not decreased at all and my OBD SOH is 94%. Additionally, I spoke with one of the 11 certified Porsche battery technicians, and he said 85% every day is perfect. He did recommend that I drain the battery down to 10-15% once every few months, and let it sit overnight and then recharge to 100% - something we are calling 'battery rebalancing'.

I remember my brother telling me to do something similar for my mobile many years ago, and he's an electronics engineer. It makes sense, and thanks for sharing this information.

I think it's really important because you never know what's going to happen in the future when you come to sell your car. I believe regulations are pretty lax at the moment because politicians want to encourage people to buy EVs, but once a lot of people have them, I'm guessing we'll be hit with a ton of new regulations and laws. One of these may be dealerships having to show the battery depreciation, etc.

I contacted a Porsche representative who replied, 'Not using fast chargers frequently as your primary way of charging, how you charge, and to what levels should not affect your battery health.'

I'm not a fan of the word 'should' it's not a definitive answer.

 

[W1NGE]

Interesting enough, in the video Jeff Dahn mentions that charging speed does not impact much. It seems high temperatures are the main issue for modern batteries and BMS.

High temps come with ultra rapid DC chsrging.

 

[Porsche-Guru]

I have a question regarding charging: Would it be better to keep the battery topped up to 85%, or should I let it drain to around 25% before recharging to 85%? What approach would be optimal for maintaining battery health?

Thanks

- What is your main charging routine? High Voltage DC or a regular AC charger?
If your regular charging is via AC, don't sweat about it.
Charge when you can, when you need it, as much as you need to; don't overthink it.

Regarding your worry about depreciation at the point of sale in a few years, I don't think a regular user can really damage the battery that much by their charging habits.

Th biggest depreciation hit will be due to later model cars having "higher range" than what the current Taycans have at the moment.

Battery range is looking to increase year on year... so a few years from now, battery range of 450+ miles would not be very surprising.

So whether your Taycan (at that point in time) returns 250 miles or 220 miles (due to battery degradation) is not going to have a massive affect on your resale value. The bigger issue will be cheaper cars available with better range in the used car market.

Enjoy the car... depreciation is part of Porsche ownership !

 

[W1NGE]

- What is your main charging routine? High Voltage DC or a regular AC charger?
If your regular charging is via AC, don't sweat about it.
Charge when you can, when you need it, as much as you need to; don't overthink it.

Regarding your worry about depreciation at the point of sale in a few years, I don't think a regular user can really damage the battery that much by their charging habits.

Th biggest depreciation hit will be due to later model cars having "higher range" than what the current Taycans have at the moment.

Battery range is looking to increase year on year... so a few years from now, battery range of 450+ miles would not be very surprising.

So whether your Taycan (at that point in time) returns 250 miles or 220 miles (due to battery degradation) is not going to have a massive affect on your resale value. The bigger issue will be cheaper cars available with better range in the used car market.

Enjoy the car... depreciation is part of Porsche ownership !

The biggest hit on depreciation (UK) is the general collapse in EV prices due to heavy discounting, confusion in the market due to government policy changes and the lack of incentives to go electric.

Hybrids are on the rise, new ICE only vehicles will continue to be sold for years to come and lack of infrastructure still a problem.

New / updated models will always have an impact too but the EV price collapse started quite some time ago and in Porsche's case long before the face lifted Taycan was announced.

Worse still are the current leasing figures which reflect low residuals on new gen 2 Taycans ahead of the first customer deliveries.

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