Home charging speed, does it make a difference?

[Jager]

If you'll monitor your individual cell temps while charging you'll find that L2 charging generates negligible heat. Heat, while generally one of the most significant user-controllable factors in Lithium battery degradation, is not a meaningful factor in home charging.

The bigger potential concern with C-Rate - how fast or how slow your vehicle charges - is Lithium plating. And to look at that, you have to tie C-Rate to pack temperature. Lithium plating can occur at even quite modest temps if the C-Rate is high enough. And as pack temps decline towards freezing, the C-Rate that your pack can accept without danger of Lithium plating plummets. Below freezing, any charging becomes a problem.

A lot of folks will quickly say that Tesla's BMS prevents all such ill effects. What I'll say is that it mostly does.

What I'd suggest, unless you live in a tropical climate where you never really see cold temps, or your vehicle lives in a garage which limits the lower ambient temps your vehicle ever sees.... is to do your L2 charging immediately after returning from a drive, rather than, say, waiting for middle-of-the-night rates.

Other than that, L2 charging at home - any rate you can possibly achieve - is pretty much a nothing burger.

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[Outdoors]

I was at the very least it would be much more efficient to charge at the lower amperage as there is not efficiency loss due to any heat generated. By Tesla admissions they say charging at higher rates does degrade the battery.

The heat of concern is storage. Having a car in a toasty AZ garage at 100F for years creates degradation. Cars in garages in northern MN tend not to have as much calendar aging as the high heat storage. Suggestion is look up calendar aging for EV's.

The cool handle for charging could maybe make the wall charger last longer, or some internal charging components, but I would say again not quantifiable on 1000 cars for your thoughts. My wall charger has charged 3 cars for many years.

Again many people do this. They know a little about batteries (RC ) than want to translate it to the car. Please take some knowledge from some of us that bought our last ICE in 2012. The myths are plentiful, and many are wrong. Based on common sense, but common sense and EV's don't always connect with some people that want to create the utopia of charging.

https://www.recurrentauto.com/research/impacts-of-fast-charging

https://www.notateslaapp.com/tesla-reference/1586/tesla-supercharging-does-not-significantly-affect-battery-life-study-reveals#:~:text=Key Findings: No Significant Impact on Battery Degradation&text=The short answer is that occasional fast charging is fine.

Home charging is not fast charging by any means.

 

[JackCypher]

The battery ais arranged in banks of a cluster of battery cells, each bank has a circuit that manages that bank of cells.

The management controls the discharge and charge rate based on the lowest performing / Worse battery in that cell. If a battery in that cell fails completely....that entire cell can take itself off line, resulting in loosing all the good remaining batteries in that cell.

This is a cost / efficency scheme, as the management circuit takes some power to operate- so you don't want a management circuit on each individual battery.

When you plug in your EV it is simply suppling power for the charger circuitry and management system to charge its cells based on that cell cluster state.

So you are really not directly charging or controlling the charge rate. The BMS: Battery Mangement System in your EV controls that.

The main BMS does determine from the input charge current how much each BMS cluster can pull to charge.

The CT is reported to have a very high current intake charge system...so.your 20amp charge is a trickle; when spread across the cells clusters.

I've put mine on the 48 tesla home.charger with a 60amp circuit breaker. With the last software update 9-2024 the rate is about 35 mile per hour....which is very slow and conservative...when you consider a tesla supercharger can now put nearly 100 miles in an hour....3x speed.

I do not think your home charger would tax the battery, it is arguably a trickle charger. Also when scheduled at night..it is cooler so the battery temperature degradation is minimal.

Recall your tesla battery preheats when you're going to supercharge.

Regards
Jack

 

[rtfitch]

Back in 2019 and 2020 when I got my 1st model 3 and Y, the recommendation from the dealership was 90%. They just switched it to 80% either a year or 2 ago.

I only burn up about 10-15% a day, so I started falling off from the 80% mark, thinking that bringing my top end down to 65% might be a safer bet...smart move or not warranted?

I charge between 12-6AM as it is free, from Tesla Elec., during that time and at 32A it is plenty of time to keep me topped off.

My question is where should I keep my top end percentage when I am out of the country for several weeks and the Beast is sitting idle, 50% when not being driven?

 

[3cyberbeast]

I have been charging my truck at 25 amps. It keeps the Charging cable cooler to the Touch. I have a six hour window where my electricity rate is lowered for car charging and it always charges up to the 80% within that timeframe on my typical daily commute. My thinking is a slow trickle charge is better than a faster charge. Below, I asked ChatGPT and this is what it came up with. What do you all think about it?

Charging a Tesla or any electric vehicle (EV) at a lower amperage can indeed have some positive effects on the longevity of the battery, though the benefits are not as significant as one might think. Here’s a breakdown:

### 1. **Heat and Battery Degradation**:
Charging at a lower amperage reduces the heat generated during the charging process. High temperatures can accelerate battery degradation over time. By charging at 25A instead of the maximum 48A, the lower heat buildup can contribute to slightly less wear on the battery, especially over the long term.

### 2. **Battery Cycles**:
Lithium-ion batteries in EVs are most affected by the number of charge cycles and the depth of discharge. Charging at a lower rate doesn’t directly affect these cycles, but a slower charge may help with more even battery conditioning, which could potentially extend overall battery health slightly.

### 3. **Diminishing Returns**:
The benefits of charging slower are incremental. Tesla batteries are designed with sophisticated thermal management systems that regulate temperature during charging and driving. Thus, even when charging at the higher 48A, the system prevents overheating, which limits degradation. This means the impact of charging slower is relatively minor compared to other factors, such as maintaining proper state-of-charge habits (e.g., not fully charging or fully draining the battery often).

### 4. **Increased Charging Efficiency**:
In terms of efficiency, there might be a slight increase in energy efficiency when charging at lower amperage because the system doesn't need to work as hard to manage higher currents and temperatures. However, this difference is often quite small.

### Conclusion:
While charging at 25A instead of 48A might offer some marginal benefits for long-term battery health due to reduced heat, Tesla's battery management system is designed to handle higher charging rates without significantly impacting the battery's longevity. Therefore, the overall impact of lower amperage charging on battery life is likely modest. For most users, the convenience of faster charging outweighs the small benefits of charging more slowly.

For optimal battery health, it’s more critical to avoid frequent fast charging (using Superchargers) and to maintain moderate charging levels (between 20-80%) in daily use.

The difference between charging at 32 amps and 48 amps primarily comes down to how much heat and stress each charging rate imposes on the battery, which affects the rate of capacity degradation over time. While both rates are safe and within Tesla's recommended parameters, higher charging rates tend to generate more heat and stress, leading to faster battery degradation over the long term.

### How Charging Affects Battery Capacity Loss

1. **Heat Generation**:
- **32 amps**: Generates less heat, which helps maintain a lower overall battery temperature during charging. Lower temperatures reduce stress on the battery cells and slow down chemical reactions that degrade the battery over time.
- **48 amps**: Generates more heat, as more energy is being pushed into the battery in a shorter amount of time. Excessive heat accelerates the chemical degradation processes, which can lead to faster capacity loss over time.

2. **Stress on Battery Cells**:
- **32 amps**: Slower charging means less stress on individual battery cells. The battery management system (BMS) has to work less to balance the cells, which results in a more even wear on the battery over time.
- **48 amps**: Charging at 48 amps puts more stress on the cells due to the faster energy transfer. The BMS works harder to maintain balance between cells, and this additional stress can contribute to a slightly faster degradation of capacity.

3. **Battery Capacity Loss Over Time**:
- **32 amps**: Charging at this rate could result in a slower rate of battery degradation. Over 10 to 20 years, the total capacity loss might be slightly less compared to faster charging rates. For example, after 10 years, the battery might lose around 15-20% of its capacity if mostly charged at 32 amps (under optimal conditions).
- **48 amps**: Charging at 48 amps could lead to a slightly faster rate of capacity loss due to the higher heat and stress. After 10 years, the battery might lose 20-25% of its capacity, depending on usage patterns and other factors like temperature and depth of discharge.

### Quantifying Capacity Loss:
- **32 amps**: Over 10 years, you could expect around **15-20% loss** in battery capacity if charged mostly at this rate, assuming moderate usage and minimal fast charging.
- **48 amps**: Over the same period, charging at 48 amps might increase the capacity loss to **20-25%**. The difference is likely to be around **5-10% more degradation** at 48 amps compared to 32 amps over a decade.

### Conclusion:
Charging at 32 amps versus 48 amps will result in less heat and stress on the battery, which slows down capacity degradation. Over 10 years, you might see around **5-10%** less battery degradation by charging at 32 amps instead of 48 amps. While both rates are safe and within Tesla’s recommendations, 32 amps will give you better longevity at the expense of slightly slower charging.

 

[Outdoors]

The difference between charging at 32 amps and 48 amps primarily comes down to how much heat and stress each charging rate imposes on the battery, which affects the rate of capacity degradation over time. While both rates are safe and within Tesla's recommended parameters, higher charging rates tend to generate more heat and stress, leading to faster battery degradation over the long term.

### How Charging Affects Battery Capacity Loss

1. **Heat Generation**:
- **32 amps**: Generates less heat, which helps maintain a lower overall battery temperature during charging. Lower temperatures reduce stress on the battery cells and slow down chemical reactions that degrade the battery over time.
- **48 amps**: Generates more heat, as more energy is being pushed into the battery in a shorter amount of time. Excessive heat accelerates the chemical degradation processes, which can lead to faster capacity loss over time.

2. **Stress on Battery Cells**:
- **32 amps**: Slower charging means less stress on individual battery cells. The battery management system (BMS) has to work less to balance the cells, which results in a more even wear on the battery over time.
- **48 amps**: Charging at 48 amps puts more stress on the cells due to the faster energy transfer. The BMS works harder to maintain balance between cells, and this additional stress can contribute to a slightly faster degradation of capacity.

3. **Battery Capacity Loss Over Time**:
- **32 amps**: Charging at this rate could result in a slower rate of battery degradation. Over 10 to 20 years, the total capacity loss might be slightly less compared to faster charging rates. For example, after 10 years, the battery might lose around 15-20% of its capacity if mostly charged at 32 amps (under optimal conditions).
- **48 amps**: Charging at 48 amps could lead to a slightly faster rate of capacity loss due to the higher heat and stress. After 10 years, the battery might lose 20-25% of its capacity, depending on usage patterns and other factors like temperature and depth of discharge.

### Quantifying Capacity Loss:
- **32 amps**: Over 10 years, you could expect around **15-20% loss** in battery capacity if charged mostly at this rate, assuming moderate usage and minimal fast charging.
- **48 amps**: Over the same period, charging at 48 amps might increase the capacity loss to **20-25%**. The difference is likely to be around **5-10% more degradation** at 48 amps compared to 32 amps over a decade.

### Conclusion:
Charging at 32 amps versus 48 amps will result in less heat and stress on the battery, which slows down capacity degradation. Over 10 years, you might see around **5-10%** less battery degradation by charging at 32 amps instead of 48 amps. While both rates are safe and within Tesla’s recommendations, 32 amps will give you better longevity at the expense of slightly slower charging.

We don't need AI here. We can do that ourselves.

 

[Alto]

I have been charging my truck at 25 amps. It keeps the Charging cable cooler to the Touch. I have a six hour window where my electricity rate is lowered for car charging and it always charges up to the 80% within that timeframe on my typical daily commute. My thinking is a slow trickle charge is better than a faster charge. Below, I asked ChatGPT and this is what it came up with. What do you all think about it?

Charging a Tesla or any electric vehicle (EV) at a lower amperage can indeed have some positive effects on the longevity of the battery, though the benefits are not as significant as one might think. Here’s a breakdown:

### 1. **Heat and Battery Degradation**:
Charging at a lower amperage reduces the heat generated during the charging process. High temperatures can accelerate battery degradation over time. By charging at 25A instead of the maximum 48A, the lower heat buildup can contribute to slightly less wear on the battery, especially over the long term.

### 2. **Battery Cycles**:
Lithium-ion batteries in EVs are most affected by the number of charge cycles and the depth of discharge. Charging at a lower rate doesn’t directly affect these cycles, but a slower charge may help with more even battery conditioning, which could potentially extend overall battery health slightly.

### 3. **Diminishing Returns**:
The benefits of charging slower are incremental. Tesla batteries are designed with sophisticated thermal management systems that regulate temperature during charging and driving. Thus, even when charging at the higher 48A, the system prevents overheating, which limits degradation. This means the impact of charging slower is relatively minor compared to other factors, such as maintaining proper state-of-charge habits (e.g., not fully charging or fully draining the battery often).

### 4. **Increased Charging Efficiency**:
In terms of efficiency, there might be a slight increase in energy efficiency when charging at lower amperage because the system doesn't need to work as hard to manage higher currents and temperatures. However, this difference is often quite small.

### Conclusion:
While charging at 25A instead of 48A might offer some marginal benefits for long-term battery health due to reduced heat, Tesla's battery management system is designed to handle higher charging rates without significantly impacting the battery's longevity. Therefore, the overall impact of lower amperage charging on battery life is likely modest. For most users, the convenience of faster charging outweighs the small benefits of charging more slowly.

For optimal battery health, it’s more critical to avoid frequent fast charging (using Superchargers) and to maintain moderate charging levels (between 20-80%) in daily use.

I’m a low amp charge guy. I like the more consistent draw from my home’s electrical system. I’ve been using Enphase/Hyundai Solar with the whole house backed up with 4 Tesla Powerwalls, monitored with an Empora Energy set up. I don’t want to worry about the AC, Pool Pump, Kitchen and a couple of car chargers all pulling max loads when the grid goes down. I’ve never been inconvenienced by the longer charge times on the vehicles.

 

[Jhodgesatmb]

There was a study done last year that attempted to find out the effect of supercharging on longevity and found basically none if it isn't used a lot. Supercharging is charging at much higher rates and temperatures than L2 at home, so I don't think that it really matters between 32A and 48A for L2 charging, and the heat would much less. There have also been studies showing that what is best for longevity is to charge to lower SOC. I have changed my charging habit to every other day (or so) to between 65% and 80% depending on expected use. My wall connector is set at 48A.

 

[Jhodgesatmb]

Back in 2019 and 2020 when I got my 1st model 3 and Y, the recommendation from the dealership was 90%. They just switched it to 80% either a year or 2 ago.

Interesting you got yours in 2019 and say that the recommendation was 90% then. We got our first M3 in 2019 and from then until now the Tesla recommendation was to 80%. Research of course tells us that the lower SOC you go dramatically increases longevity.

 

[igs]

I only burn up about 10-15% a day, so I started falling off from the 80% mark, thinking that bringing my top end down to 65% might be a safer bet...smart move or not warranted?

I charge between 12-6AM as it is free, from Tesla Elec., during that time and at 32A it is plenty of time to keep me topped off.

My question is where should I keep my top end percentage when I am out of the country for several weeks and the Beast is sitting idle, 50% when not being driven?

Tesla recommends 15% - 50%

Tesla: "To maintain service life, the battery pack should be stored at a state of charge (SOC) of 15 to 50%."

 

[3cyberbeast]

I have been charging my truck at 25 amps. It keeps the Charging cable cooler to the Touch. I have a six hour window where my electricity rate is lowered for car charging and it always charges up to the 80% within that timeframe on my typical daily commute. My thinking is a slow trickle charge is better than a faster charge. Below, I asked ChatGPT and this is what it came up with. What do you all think about it?

Charging a Tesla or any electric vehicle (EV) at a lower amperage can indeed have some positive effects on the longevity of the battery, though the benefits are not as significant as one might think. Here’s a breakdown:

### 1. **Heat and Battery Degradation**:
Charging at a lower amperage reduces the heat generated during the charging process. High temperatures can accelerate battery degradation over time. By charging at 25A instead of the maximum 48A, the lower heat buildup can contribute to slightly less wear on the battery, especially over the long term.

### 2. **Battery Cycles**:
Lithium-ion batteries in EVs are most affected by the number of charge cycles and the depth of discharge. Charging at a lower rate doesn’t directly affect these cycles, but a slower charge may help with more even battery conditioning, which could potentially extend overall battery health slightly.

### 3. **Diminishing Returns**:
The benefits of charging slower are incremental. Tesla batteries are designed with sophisticated thermal management systems that regulate temperature during charging and driving. Thus, even when charging at the higher 48A, the system prevents overheating, which limits degradation. This means the impact of charging slower is relatively minor compared to other factors, such as maintaining proper state-of-charge habits (e.g., not fully charging or fully draining the battery often).

### 4. **Increased Charging Efficiency**:
In terms of efficiency, there might be a slight increase in energy efficiency when charging at lower amperage because the system doesn't need to work as hard to manage higher currents and temperatures. However, this difference is often quite small.

### Conclusion:
While charging at 25A instead of 48A might offer some marginal benefits for long-term battery health due to reduced heat, Tesla's battery management system is designed to handle higher charging rates without significantly impacting the battery's longevity. Therefore, the overall impact of lower amperage charging on battery life is likely modest. For most users, the convenience of faster charging outweighs the small benefits of charging more slowly.

For optimal battery health, it’s more critical to avoid frequent fast charging (using Superchargers) and to maintain moderate charging levels (between 20-80%) in daily use.

I have been charging my truck at 25 amps. It keeps the Charging cable cooler to the Touch. I have a six hour window where my electricity rate is lowered for car charging and it always charges up to the 80% within that timeframe on my typical daily commute. My thinking is a slow trickle charge is better than a faster charge. Below, I asked ChatGPT and this is what it came up with. What do you all think about it?

Charging a Tesla or any electric vehicle (EV) at a lower amperage can indeed have some positive effects on the longevity of the battery, though the benefits are not as significant as one might think. Here’s a breakdown:

### 1. **Heat and Battery Degradation**:
Charging at a lower amperage reduces the heat generated during the charging process. High temperatures can accelerate battery degradation over time. By charging at 25A instead of the maximum 48A, the lower heat buildup can contribute to slightly less wear on the battery, especially over the long term.

### 2. **Battery Cycles**:
Lithium-ion batteries in EVs are most affected by the number of charge cycles and the depth of discharge. Charging at a lower rate doesn’t directly affect these cycles, but a slower charge may help with more even battery conditioning, which could potentially extend overall battery health slightly.

### 3. **Diminishing Returns**:
The benefits of charging slower are incremental. Tesla batteries are designed with sophisticated thermal management systems that regulate temperature during charging and driving. Thus, even when charging at the higher 48A, the system prevents overheating, which limits degradation. This means the impact of charging slower is relatively minor compared to other factors, such as maintaining proper state-of-charge habits (e.g., not fully charging or fully draining the battery often).

### 4. **Increased Charging Efficiency**:
In terms of efficiency, there might be a slight increase in energy efficiency when charging at lower amperage because the system doesn't need to work as hard to manage higher currents and temperatures. However, this difference is often quite small.

### Conclusion:
While charging at 25A instead of 48A might offer some marginal benefits for long-term battery health due to reduced heat, Tesla's battery management system is designed to handle higher charging rates without significantly impacting the battery's longevity. Therefore, the overall impact of lower amperage charging on battery life is likely modest. For most users, the convenience of faster charging outweighs the small benefits of charging more slowly.

For optimal battery health, it’s more critical to avoid frequent fast charging (using Superchargers) and to maintain moderate charging levels (between 20-80%) in daily use.

Has anyone changed their charging habits due to this post?

 

[igs]

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