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Getting NEMA 14-50 Installed tomorrow

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Leafdriver333

Somewhat Active Member
Mar 21, 2019
1,109
947
usa
An electrician is coming out tomorrow to install an outlet for me.
NEMA 14-50 with 40A all I need?

My commute is only 24 miles each day so I decided to get 240v outlet installed. That way I will be charging only once a week and my batteries will go through only about 52 cycles of charging instead of 356 cycles a year on slow 110v charger. And the batteries will last 7 times longer. That's my reason for getting fast charging even though I only travel 24 miles a day anyway.
 
Agree with others, 50A breaker. The electrician should tend to know that, if not, get another electrician.

Your math is off on the number of cycles and battery life. That's not the way it works. Although I know that's what some self-proclaimed experts have said.

Think of it this way, if what you said was right, then you could kill a battery by just plugging it into 120V for 1 second, unplugging for 1 second and repeating for an entire day or two. That won't kill a battery.
 
An electrician is coming out tomorrow to install an outlet for me.
NEMA 14-50 with 40A all I need?

My commute is only 24 miles each day so I decided to get 240v outlet installed. That way I will be charging only once a week and my batteries will go through only about 52 cycles of charging instead of 356 cycles a year on slow 110v charger. And the batteries will last 7 times longer. That's my reason for getting fast charging even though I only travel 24 miles a day anyway.
That’s not how it works. RTFM.
 
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Get 50A breaker and use 50A wiring.

60A wiring would be even better to be a bit more future proof.

Also, the outlet needs to be upside-down from convention. Look at the plug on the end of your mobile connector for the proper orientation. Ground on TOP.

Show this to the electrician if he's not already aware:
https://www.tesla.com/sites/default.../NEMA_14-50_installation_guide_NA_US_2017.pdf

I wished I had that diagram when I was building my house in 2013.
Builder installed our 240V after the walls had gone up & did everything opposite from optimal location for the outlet to orientation of the ground pin.
 
I wished I had that diagram when I was building my house in 2013.
Builder installed our 240V after the walls had gone up & did everything opposite from optimal location for the outlet to orientation of the ground pin.
At the least, you should be able to rotate the outlet pretty easily provided there's enough slack in the wires.

You would obviously want to shut off the power first. Get someone who's familiar with electricity if you don't feel comfortable doing it yourself.
 
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14-50 should be installed with 50 amps. Going with a larger gauge wire isn't a bad idea but the standard is more than enough for most of us.

I had a NEMA 14-50 outlet installed with 50A, but for just a little more money, I had the electrician install wiring good for 60A so I could more easily upgrade to a Tesla wall charger and 60A service in the future if I wanted.
 
So using the car for 20% and charging up to 90% everyday is just as good as using it for 60% and charging every 3 days?
It is hard to believe.
Cycle is a cycle.
It's not nearly as simple as you just put it. I honestly don't know all the nitty gritty details myself, but the battery management system does not treat the battery pack as one HUGE battery. It will selectively charge and discharge any number of the thousands of battery cells as it sees fit. Plugging it in everyday does not mean charging every cell every day. Likewise, driving the car does not mean every cell gets discharged all the time.
 
So using the car for 20% and charging up to 90% everyday is just as good as using it for 60% and charging every 3 days?
It is hard to believe.
Cycle is a cycle.

The cells are neutral at 50%. This is the least damaging to them, and where you want the cells to sit at when doing long term storage on them.

You should charge it based on expected usage, while staying away from the extremes when possible (0% and 100%).

50% for long term storage.
40% to 60% if you only need to use 20% capacity daily.
30% to 70% if you only need to use 40% capacity daily.
20% to 80% if you only need to use 60% capacity daily.
10% to 90% if you only need to use 80% capacity daily.

Tesla will say to use 90% as your target, because its simpler to explain to consumers the nuances of battery charging. Needless to say, 80% is better on the battery's longevity than 90%, and 70% better yet still. But there is diminishing returns lower than that, so you have to weigh a theoretical capacity loss (which could be 400k miles away) to real world range requirements.
 
The cells are neutral at 50%. This is the least damaging to them, and where you want the cells to sit at when doing long term storage on them.

You should charge it based on expected usage, while staying away from the extremes when possible (0% and 100%).

50% for long term storage.
40% to 60% if you only need to use 20% capacity daily.
30% to 70% if you only need to use 40% capacity daily.
20% to 80% if you only need to use 60% capacity daily.
10% to 90% if you only need to use 80% capacity daily.

Tesla will say to use 90% as your target, because its simpler to explain to consumers the nuances of battery charging. Needless to say, 80% is better on the battery's longevity than 90%, and 70% better yet still. But there is diminishing returns lower than that, so you have to weigh a theoretical capacity loss (which could be 400k miles away) to real world range requirements.
“Better” may be statistically significant but it’s not clinically meaningful. After five or six years of charging to 90% every night, and 100% for trips, the Model S batteries have done just fine. For example my Model S 60 lost 5% of rated range that way in five years of ownership. You’re not going to do better than that no matter how you baby the battery.

This is not a Leaf. Don’t worry about the battery. Just enjoy the car.
 
“Better” may be statistically significant but it’s not clinically meaningful. After five or six years of charging to 90% every night, and 100% for trips, the Model S batteries have done just fine. For example my Model S 60 lost 5% of rated range that way in five years of ownership. You’re not going to do better than that no matter how you baby the battery.

This is not a Leaf. Don’t worry about the battery. Just enjoy the car.

Tesla has done an amazing job with the batteries. The fact that there are cars with over 500k miles on them and still >80% capacity is a testament to that.

However, when discussing best practices, avoiding extremes of charge/discharge cycles as well as avoiding deep discharge cycles when possible is still the rule of thumb. Chemistry doesn't care what brand name is on the package.

Is what I said true? Yes.

Do you have to follow it? No, you're likely fine charging to 90%. Tesla says 90% is fine. You can also find Musk posting on twitter that 80% is better, and battery experts saying 70% better still. It's all about diminishing returns and how far you want to go with it while still allowing normal operation of the vehicle.
 
Now faster charging at my disposal, I can afford to keep it between 30% and 70% everyday. And when I know if I will need more the next day, I can charge more the night before.

With 110V, I don't have that luxury. If I am at 50% today, the best I can do is 75% by the next morning.


however, the youtuber, "like tesla", had to charge it to 100% several times to re-balance the cells because she charged to 20-70% everyday...

I will charge to 80% and use it down to 25% and charge back to 80% to minimized the number of charging cycle.
 
What is the advantage of the Tesla wall charger $500?

Since your context seems to be a comparison to the portable EVSE that comes with the Tesla, plugged into a NEMA 14-50 outlet:
  • Having a second EVSE means that you can keep one permanently with the car, without the hassle of putting it in the car every time you drive off. For most people, this is just a little precaution, like having a spare tire or fix-a-flat kit, but it's not likely you'll need it on any given trip. Some people might use it frequently, though -- say, if there's an outlet you can use to charge at work.
  • The Tesla wall connector charges the LR Model 3 at a faster rate than the included portable one -- 48 amps vs. 32 amps (assuming optimal wiring/amperage to both devices). This isn't likely to be a big deal unless you drive a lot, although it could be important once every decade or two.
  • If you hard-wire an EVSE, it won't be accidentally unplugged or have problems if the plug works itself loose. This type of problem is unlikely, though.
  • If you want to charge outside, Tesla's wall connector, as well as some (but not all) third-party EVSEs, are weather-proof. I have yet to see definitive information on how weather-proofed the portable unit is; most people seem to assume it's kind-of sort-of weather-proof, but it's best to protect it from the worst of the elements.
  • Tesla's wall charger comes with a built-in holster to hold the connector that plugs into the car. This can help a little with cable management. (Yes, this is a very minor advantage.)
Compared to third-party EVSEs, the Tesla unit has the right plug for a Tesla car; other EVSEs all, to the best of my knowledge, have J1772 plugs, which require adapters. (Teslas come with such an adapter; or you can buy another for $95.) Most third-party EVSEs are a little more expensive and/or deliver less power to the car than Tesla's, too. OTOH, third-party EVSEs can be used with non-Tesla vehicles, so if you plan to buy a second non-Tesla EV, or think you'll replace a Tesla with some other brand in the near future, buying a J1772 EVSE might make sense. Then too, under such circumstances, it might make more sense to use your portable Tesla EVSE for now and then buy a J1772 EVSE when you actually buy an EV that needs it.