What is best for the battery?

[super20g]

I charge to 90% everynight because I love mashing the pedal whenever I get the chance lol


Does anyone know if below a certain %, the car becomes slower?

Is 75-90% the same power? I noticed just a little.

There are graphs I saw on a thread on reddit that I don't have handy, but yes, as SoC goes down, so does power output.

 

[reheat]

I charge to 90% everynight because I love mashing the pedal whenever I get the chance lol


Does anyone know if below a certain %, the car becomes slower?

Is 75-90% the same power? I noticed just a little.

From a Reddit thread on AWD power:

Between 80-90% SOC the Model 3 AWD makes a peak power of 314 kW (421 hp). The values above 90% SOC might be slightly higher, but as it's not yet warm enough outside I wasn't able to test in that range with an ideal battery temperature.

At 70% SOC the peak power drops to 299 kW (401 hp), a 5% drop from the power of a full charge.

At 50% SOC the peak power is 288 kW (386 hp), 8% less than at full charge.

At 30% SOC the peak power is 271 kW (363 hp), 14% less than at full charge.

At 10% SOC the peak power is 242 kW (325 hp), 23% less than at full charge.

 

[David99]

At 10% SOC the peak power is 242 kW (325 hp), 23% less than at full charge.

Interesting! Matches my measurements in my Model S exactly.

 

[dsvick]

While I agree there is little difference in battery degradation in the long run, people still like to do it. It is their car and it brings them joy to take care of it. It's the same as washing the car, waxing it, taking care of the interior, doing all kinds of things to keep the car nice and working well. I have not heard a single person saying, 'stop worrying about your paint, just drive it' when the question about how to wash the car has been brought up.

I'm not sure I'd equate battery life to paint. Regardless though, I made my comments because there are a lot of new owners out there that are under the impression that they have to go to the extremes and calculate exactly the perfect amount of charge and amperage based on miles to be driven, current temperature, altitude above sea level, and what they had for lunch the previous day. Sure if they enjoy that sort of thing then they can certainly go right ahead and do it, but if not, then they don't need to.

 

[Glamisduner]

I generally drive cars for 8-10 years before getting something new but keep the old vehicles and still maintain and drive them intermittently.

My wife just sold her 18 year highlander, and I sold my 14 year old truck (but only to buy another 14 year old truck better suited for heavy towing).

From what I understand:

• Maintaining a 70-90% battery charge state is best for the battery health long term
• Battery heat is bad (eg, >100 degrees outside)
• Supercharging is bad for the battery (lots of stress on the battery + heat)

My questions are:

• Assuming I can charge every day
  • Is charging at a lower amperage better for the battery health (thinking: less heat, lower stress)
    • eg, should I recharge at 8 or 10 amps instead of 30+ because I am at the office for >8 hours -- so don't need to 'rush' the charge at full L2 speed.
• I use 80 miles of range per day
  • Should I charge every day to get it back into the 70-90% charge range or wait until I am in the 30-50% range and then charge (eg, every ~3-4 days vs daily)

Generally, the lower the charge rate the easier it is on a lithium battery. Not sure how much it matters with these giant tesla batteries.

People overthink this way too much. Just leave it plugged in whenever you can. Set your upper charger limit to what you need, somewhere between 50-90%. Charge to 100% if immediately going on a trip. When supercharging, plan to arrive at between 10-20% battery at the next supercharger, charge to 70% or so and move into the next charger if you can, when you get to your destination plug into something.

What is considered immediate? My charge hours are 12:00-6:00am. So would charging to 100%, then taking it on a road trip at say, I dunno, 4:00 that night be immediate enough?

I have been charging to 75-78% every day, which gets be home with about 35%-40% battery left. I feel this is ideal for my commute as far as charge cycles and battery wear. Charging to only 80% gets you most of the way there, but decreasing to 70% REALLY puts less cycles (might not be practical though). Dropping below 30% is likely not great on the battery either, but degradation isn't usually bad until lower levels.

Check out the study on the nissan leaf batteries below:
Appears 75-25% is the best for battery life of the charge ranges tested
https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

Is the model 3 battery actually charged to 100% when we set it there?
Is the model 3 battery actually at 0% when discharged all the way? (I doubt it, because that would be hazardous) So when we take our battery's down to say 15%, what are they really at?

And a new question.
Is it harder on the battery to drop below 15% charge, or stopping to supercharging it, rather than destination charge? What if you drop under 15% but charge up immediately?

 

[David99]

What is considered immediate? My charge hours are 12:00-6:00am. So would charging to 100%, then taking it on a road trip at say, I dunno, 4:00 that night be immediate enough?

Dashboard for Tesla is an app that allows you to set a time when charging should be finished. It is very useful because it starts charging automatically to be done just when you set it and want to leave. This way the battery will stay at a lower state of charge for longer on average which is better for battery life. I use it to charge my car on a daily basis. It is especially useful for road trips when you want to charge to 100% and not have the car sit like that for long.

I have been charging to 75-78% every day, which gets be home with about 35%-40% battery left.

That's perfect. The difference between 100% and 90% is significant. The difference between 90% and 80% far less. And even less between 80 and 70%. So there is little point to charge below 80%. And yes of course, don't discharge too low.

Is the model 3 battery actually charged to 100% when we set it there?

Yes it is. All research by smart people who have taken Tesla batteries apart confirm that's how Tesla has been doing it for all cars. Exception are software limited cars. They make the top part unavailable.

Is the model 3 battery actually at 0% when discharged all the way? (I doubt it, because that would be hazardous) So when we take our battery's down to say 15%, what are they really at?

Definitely not. Again, all Teslas have a buffer that prevents a total discharge. Elon tweeted about it. Data from all cars show that as well. It's aprox 4-5%.

And a new question.
Is it harder on the battery to drop below 15% charge, or stopping to supercharging it, rather than destination charge? What if you drop under 15% but charge up immediately?

According to every battery manufacturer it would be best to give the battery a resting period after it's been discharged and after it's been charged. In reality that's often not how we use cars. As for charge speed at low levels. That's what the BMS takes care of. It will only allow a save charge speed depending on battery SoC, temperature and recent usage.

 

[Glamisduner]

Dashboard for Tesla is an app that allows you to set a time when charging should be finished. It is very useful because it starts charging automatically to be done just when you set it and want to leave. This way the battery will stay at a lower state of charge for longer on average which is better for battery life. I use it to charge my car on a daily basis. It is especially useful for road trips when you want to charge to 100% and not have the car sit like that for long.



That's perfect. The difference between 100% and 90% is significant. The difference between 90% and 80% far less. And even less between 80 and 70%. So there is little point to charge below 80%. And yes of course, don't discharge too low.


Yes it is. All research by smart people who have taken Tesla batteries apart confirm that's how Tesla has been doing it for all cars. Exception are software limited cars. They make the top part unavailable.



Definitely not. Again, all Teslas have a buffer that prevents a total discharge. Elon tweeted about it. Data from all cars show that as well. It's aprox 4-5%.



According to every battery manufacturer it would be best to give the battery a resting period after it's been discharged and after it's been charged. In reality that's often not how we use cars. As for charge speed at low levels. That's what the BMS takes care of. It will only allow a save charge speed depending on battery SoC, temperature and recent usage.

Unfortunately charging closer to trip time costs me 5x as much.

 

[Evoforce]

Some people drive more. I have aprox 1200 cycles on my Model S battery in 5 years and it has 12% degradation. The commonly accepted point where the life of a battery is considered at the end is at 80% of it's original capacity (20% degradation). I would hope the Model 3 battery will be better than that after 1500 cycles.

Are you sure you have that many cycles? Every time you plug in isn't considered a cycle.

 

[woodisgood]

Are you sure you have that many cycles? Every time you plug in isn't considered a cycle.

What would be considered a cycle? Just the total kwh of the battery, i.e. ~75?

 

[Dre78]

While I agree there is little difference in battery degradation in the long run, people still like to do it. It is their car and it brings them joy to take care of it. It's the same as washing the car, waxing it, taking care of the interior, doing all kinds of things to keep the car nice and working well. I have not heard a single person saying, 'stop worrying about your paint, just drive it' when the question about how to wash the car has been brought up.

LOL! True true.

I'm middle of the road on both charging and washing, but love reading the OCD threads and watching videos on both regardless.

My 2 cents on the matter: Model 3's battery management system is quite aggressive to conserving battery life. After purchase, every time I'd use an Urban Supercharger with battery above 40%, it would never get above 30kWh. Then one day I let state of charge dip to 20%, and now I see 60+kWh rates when below 60%. I'm wondering if I keep SoC above 50% how long (if ever) until it will revert to keeping at or below 30kWh.

 

[ReddyLeaf]

Did you buy any other cars to enjoy? 3 cars in a lifetime only?

Not everyone swaps vehicles constantly. I have only bought three, and I only got rid of the first one because I’m done with gas. I bought my first and only gas vehicle 25 years ago. My second vehicle, A 2011 Leaf, is still holding up on the original (lousy) battery (well at least for in-town use). Oh, and on topic, as an OCD scientist, I keep both EV batteries around 40-60% SOC, charging daily as much as needed to keep them near 50% most of the time. My cars sit idle >20 hr/day and my daily driving needs are much less than average, so why not treat them the best? However, the Tesla is for road trips, so I supercharge a lot, and often to 90% or even 100% when going off the SC grid.

 

[David99]

Are you sure you have that many cycles? Every time you plug in isn't considered a cycle.

Tesla keeps track of the total amount of energy. Kind of a battery energy odometer. It's from a Model S. I don't think there are Model 3s out there with more than 200k miles.

 

[David99]

Unfortunately charging closer to trip time costs me 5x as much.

Ouch! In those cases, charge to 95% when it's cheap and then charge the rest just before you leave. Or just charge to 95% during off peak and forget about the last 5%. Plenty of Superchargers within range from Escondido.

 

[ElectricLee]

Charge ANY way you like.

1. The motor is rated for 1 million miles.
2. The battery is rated for 300,000 to 500,000 miles.
3. The body is built for 1 million miles.

all of those are way longer than any car you may have ever owned in general.