Master Thread: Definitive 14-50 NEMA Outlet Guide

[zroger73]

Just a little thought to keep in mind: Slow charging (particularly 120 volt, 12/16 amp) is less efficient than charging at faster rates because the fixed portions of charging overhead remain active longer.

When I charge using the Mobile Connector at 120V/15A, I get 85% charging efficiency. When I charge using the Wall Connector at 240V/48A, I get 97% efficiency. I drive my Model Y about 45 miles per day and spend about $50 per month for 240V/48A charging at 12¢/kWh. Even though 120V/15A charging is fast enough for me, I would be wasting about $6 per month due to the losses associated with slower charging. Granted, that's not much, but I'll sure accept $6 per month from anyone who is willing to give it to me!

The moral of this story is: For the greatest efficiency, charge as fast as you can at home.

I think I’ve read Gen 2 have an advantage for power sharing?
A new TWC at $475 saves needing a 14-50R and GFI breaker, and seems price competive, I only have 1 but it said it could share “in the future”

In my case, the net cost for a Wall Connector was far less than the cost of a Mobile Connector because my electric company gave me a $250 rebate for installing a WC.

$425 Wall Connector
($250) less rebate
$175 net cost

$230 Mobile Connector
$50 Bryant 9450FR receptacle
$180 Square D QO 50A GFCI breaker
$460 total cost

Note that I did not include the cost of wire, conduit, or labor since I did the installation myself and they were near my panel, so the cost was minimal. Even if I already had a receptacle for the Mobile Connector, the cost would be similar after the rebate.

Also note that I have both setups for a few reasons:

• There are no fast chargers in my area, so home charging is critical.
• If my Wall Connector fails, I need a backup charging method until I can replace it.
• A Mobile Connector gives me a backup charging method for home and allows me to charge at work if my power is out at home, for example.

 

[jeremymc7]

Different chargers have different advantages and disadvantages which may or may not make a difference depending on which vehicle(s) you have and your specific use case.

Each subsequent version is not better in every way over the previous version.

 

[jeremymc7]

Just a little thought to keep in mind: Slow charging (particularly 120 volt, 12/16 amp) is less efficient than charging at faster rates because the fixed portions of charging overhead remain active longer.

When I charge using the Mobile Connector at 120V/15A, I get 85% charging efficiency. When I charge using the Wall Connector at 240V/48A, I get 97% efficiency. I drive my Model Y about 45 miles per day and spend about $50 per month for 240V/48A charging at 12¢/kWh. Even though 120V/15A charging is fast enough for me, I would be wasting about $6 per month due to the losses associated with slower charging. Granted, that's not much, but I'll sure accept $6 per month from anyone who is willing to give it to me!

The moral of this story is: For the greatest efficiency, charge as fast as you can at home.

Don’t disagree with any of this. However isn’t different amounts of more or less wear on the battery as well that should be factored in. Just not the efficiency of the connection at various levels.

 

[KJD]

Don’t disagree with any of this. However isn’t different amounts of more or less wear on the battery as well that should be factored in. Just not the efficiency of the connection at various levels.

Home charging at 48 amps will not add any wear to your battery in any way shape or form.

Best way to charge to prevent battery degradation?

 

[zroger73]

Don’t disagree with any of this. However isn’t different amounts of more or less wear on the battery as well that should be factored in. Just not the efficiency of the connection at various levels.

Pushing even 11,500 watts (the maximum capability of the Wall Connector) into the battery at home is very gentle compared to pushing 250,000 watts into it at a Supercharger.

 

[Feathermerchan]

Typical testing for Lithium cells is charging at 1C and discharging at 1C. That would be about 75 kW on our Model 3 and Y cars. My Y and 3 use about 20kW at 70 mph. So charging at ~11kW is really nothing.

 

[jeremymc7]

Not an expert and internet is full of miss information but my understanding is that faster charging is more efficient and waste less energy but conversely faster charging will increase the rate at which an EV's battery capacity will decline and most experts agree that slow charging is still the best way to charge an EV, since it uses low voltage and allows ample time for ion stabilization.
So seems like a mixed bag and that there is maybe a better ground between trickle charging and max charging.

Replacement battery is going to cost a lot more than the extra cost or lower efficiency charging but even Tesla has stated that high speed charging over 200k was a max of 20% degradation which in itself isn’t a huge difference over typical degradation.

 

[jeremymc7]

Home charging at 48 amps will not add any wear to your battery in any way shape or form.

Home charging at 48 amps will not add any wear to your battery in any way shape or form.

Best way to charge to prevent battery degradation?

Pretty sure theres a difference between “NOT add ANY wear to your battery in ANY way shape or form.” Vs. negligible or minimal wear of which the exact amount is questionable or debatable where “will not in any way” kind of means absolutely ZERO impact. Just clarifying.

 

[CyberGus]

Pretty sure theres a difference between “NOT add ANY wear to your battery in ANY way shape or form.” Vs. negligible or minimal wear of which the exact amount is questionable or debatable where “will not in any way” kind of means absolutely ZERO impact. Just clarifying.

The battery pack degrades over time, regardless of usage. Charging habits can affect the extent of degradation. Level 2 charging has a negligible effect on pack health, since it is degrading just sitting there whether you charge it or not.

Sure, it can be "more efficient" to charge at higher rates, since there's overhead (car computer, thermal management. etc.) but again this doesn't really modify degradation.

 

[zroger73]

Not an expert and internet is full of miss information but my understanding is that faster charging is more efficient and waste less energy but conversely faster charging will increase the rate at which an EV's battery capacity will decline and most experts agree that slow charging is still the best way to charge an EV, since it uses low voltage and allows ample time for ion stabilization.
So seems like a mixed bag and that there is maybe a better ground between trickle charging and max charging.

Replacement battery is going to cost a lot more than the extra cost or lower efficiency charging but even Tesla has stated that high speed charging over 200k was a max of 20% degradation which in itself isn’t a huge difference over typical degradation.

Compared to the 250,000 watts Superchargers shove into batteries, the 11,500 watts a Wall Connector shoves into the battery is "trickle charging".

If you're trying to reach some type of Guinness record for the lowest degradation and longest battery life, charge to 51%, drain to 49%, drive the vehicle only during the Spring and Fall when neither cooling nor heating is required, and store the car in a climate-controlled garage in the Summer and Winter, drive at 35 MPH everywhere, and charge at 120 volts and 8 amps.

For everyone else, just follow Tesla's best practices:

• Don't let the battery get "too low".
• Limit daily charging to <90%, but it's okay to charge to 100% occasionally if necessary for long trips.
• Minimize (or avoid, if possible) use of DC fast charging (Superchargers) unless absolutely necessary.

Tesla must be confident these best practices will allow the battery to retain at least 70% of its original capacity over 8 years or 1xx,xxx miles (which is longer than most of us will own the same vehicle) since they guarantee the battery that long.

The reality is that obsessing over battery care will almost certainly yield less degradation and longer life, but not by a margin that is significant to the vast majority. Someone who exclusively supercharges from 10% to 90% every time might have 15% degradation after 8 years while someone trying for a record might have 10% degradation. All batteries will degrade. Just follow Tesla's instructions and enjoy the vehicle.

 

[jeremymc7]

I could care less either way really for my purposes. Just participating the the thread. I have free supercharging so it’s 95% of my charging, typically 85-90% capacity. 4% charging at free work charger, since I’m 99% work from home these days, and 1% at home after midnight on 20A as needed when I don’t have time to use the SC the next day and car is low. Only keeping car 4-8 years and only put on 12k miles in last 2.5 years as well. Any potentially slightly above battery degradation on my car is going to largely offset by the unusually low miles. Not really concerned about resale anyway. Didn’t buy it for resale.

 

[n2mb_racing]

Just a little thought to keep in mind: Slow charging (particularly 120 volt, 12/16 amp) is less efficient than charging at faster rates because the fixed portions of charging overhead remain active longer.

When I charge using the Mobile Connector at 120V/15A, I get 85% charging efficiency. When I charge using the Wall Connector at 240V/48A, I get 97% efficiency. I drive my Model Y about 45 miles per day and spend about $50 per month for 240V/48A charging at 12¢/kWh. Even though 120V/15A charging is fast enough for me, I would be wasting about $6 per month due to the losses associated with slower charging. Granted, that's not much, but I'll sure accept $6 per month from anyone who is willing to give it to me!

The moral of this story is: For the greatest efficiency, charge as fast as you can at home.


In my case, the net cost for a Wall Connector was far less than the cost of a Mobile Connector because my electric company gave me a $250 rebate for installing a WC.

$425 Wall Connector
($250) less rebate
$175 net cost

$230 Mobile Connector
$50 Bryant 9450FR receptacle
$180 Square D QO 50A GFCI breaker
$460 total cost

Note that I did not include the cost of wire, conduit, or labor since I did the installation myself and they were near my panel, so the cost was minimal. Even if I already had a receptacle for the Mobile Connector, the cost would be similar after the rebate.

Also note that I have both setups for a few reasons:

• There are no fast chargers in my area, so home charging is critical.
• If my Wall Connector fails, I need a backup charging method until I can replace it.
• A Mobile Connector gives me a backup charging method for home and allows me to charge at work if my power is out at home, for example.

Yes, but 240v 16a or 32a is just as efficient and cheaper.

 

[Carsmak]

Compared to the 250,000 watts Superchargers shove into batteries, the 11,500 watts a Wall Connector shoves into the battery is "trickle charging".

If you're trying to reach some type of Guinness record for the lowest degradation and longest battery life, charge to 51%, drain to 49%, drive the vehicle only during the Spring and Fall when neither cooling nor heating is required, and store the car in a climate-controlled garage in the Summer and Winter, drive at 35 MPH everywhere, and charge at 120 volts and 8 amps.

For everyone else, just follow Tesla's best practices:

• Don't let the battery get "too low".
• Limit daily charging to <90%, but it's okay to charge to 100% occasionally if necessary for long trips.
• Minimize (or avoid, if possible) use of DC fast charging (Superchargers) unless absolutely necessary.

Tesla must be confident these best practices will allow the battery to retain at least 70% of its original capacity over 8 years or 1xx,xxx miles (which is longer than most of us will own the same vehicle) since they guarantee the battery that long.

The reality is that obsessing over battery care will almost certainly yield less degradation and longer life, but not by a margin that is significant to the vast majority. Someone who exclusively supercharges from 10% to 90% every time might have 15% degradation after 8 years while someone trying for a record might have 10% degradation. All batteries will degrade. Just follow Tesla's instructions and enjoy the vehicle.

Ok, but what about all of us who just acquired a M3SR, and received 3 months of Supercharging for free, who are still attempting to learn what to do. Do we just say “screw this” that’s what the 8y100k is for? Would they deny that warranty based on early ownership issue?

Without knowing an actual owner who lives near myself, (High Desert So. Calif) and without any home charging capacity, other than some questionable 110v outlets which have easily popped circuit breakers with simple power equipment. We’ve SC’d 3x so far and miscommunications between the SO & I, each time has been to 99% (2x) and 100% (1).

Also, the first and third time we got to 99% in an acceptable amount of time, but basically, the vehicle stated “calibrating” then “charging“ and on our very first charge did this repeatedly for 25-30 minutes? So unfamiliar and trying to figure out what to d, we sat there together watching the display and waiting. Finally the SO was “PO’d” and decided to just leave, as we’d been there nearly an hour and a half. As soon as she disconnected, it displayed 100%

And please all feel free to leave rude comments and tell me how I posTed in the wrong plac, et all. Trust me, I have looked, searched and I’m over it.

Carry on

 

[zroger73]

Yes, but 240v 16a or 32a is just as efficient and cheaper.

Take two identical Teslas.

Charge one at 240V/48A. Let's say it takes about one hour to charge. During that one hour, the vehicle is awake. Most of the power goes into the battery, but some is used for other purposes.

Charge the other at 240V/16A. That one takes about three hours to charge. The same amount of power goes into the battery, but over a longer period of time requiring the vehicle to be awake for three hours instead of one hour, so the power required for other purposes just increased by 3x.

Charging at 240V/16A is less efficient than charging at 240V/48A. Depending on how much you drive and what you pay for electricity, this may amount to less than $1 per month or it may cost several dollars per month, but the fact remains that slower charging is less efficient.

 

[zroger73]

Ok, but what about all of us who just acquired a M3SR, and received 3 months of Supercharging for free, who are still attempting to learn what to do. Do we just say “screw this” that’s what the 8y100k is for? Would they deny that warranty based on early ownership issue?

Without knowing an actual owner who lives near myself, (High Desert So. Calif) and without any home charging capacity, other than some questionable 110v outlets which have easily popped circuit breakers with simple power equipment. We’ve SC’d 3x so far and miscommunications between the SO & I, each time has been to 99% (2x) and 100% (1).

Also, the first and third time we got to 99% in an acceptable amount of time, but basically, the vehicle stated “calibrating” then “charging“ and on our very first charge did this repeatedly for 25-30 minutes? So unfamiliar and trying to figure out what to d, we sat there together watching the display and waiting. Finally the SO was “PO’d” and decided to just leave, as we’d been there nearly an hour and a half. As soon as she disconnected, it displayed 100%

And please all feel free to leave rude comments and tell me how I posTed in the wrong plac, et all. Trust me, I have looked, searched and I’m over it.

Carry on

In your case, I'd use the 3 free months, but limit charging to 80%. During that three months, I'd have the Wall Connector installed. Test it to make sure it works. Once the three months are up, charge daily at home. Charge only as much as necessary for the day's driving. I, for example, charge to 60%. After my daily commute and errands, I have 40-45% charge left. I plug in then charge back to 60%. This keeps the battery within a relatively narrow range around 50%, which is ideal for minimizing degradation. If I decide to drive a bit farther than usual on the weekend, for example, then I'll charge to 80-90%.

EDIT: I didn't consider that you might have an LFP battery. If so, ignore my advice and charge to 100%.

 

[Genie]

Ok, but what about all of us who just acquired a M3SR, and received 3 months of Supercharging for free, who are still attempting to learn what to do. Do we just say “screw this” that’s what the 8y100k is for? Would they deny that warranty based on early ownership issue?

Without knowing an actual owner who lives near myself, (High Desert So. Calif) and without any home charging capacity, other than some questionable 110v outlets which have easily popped circuit breakers with simple power equipment. We’ve SC’d 3x so far and miscommunications between the SO & I, each time has been to 99% (2x) and 100% (1).

Also, the first and third time we got to 99% in an acceptable amount of time, but basically, the vehicle stated “calibrating” then “charging“ and on our very first charge did this repeatedly for 25-30 minutes? So unfamiliar and trying to figure out what to d, we sat there together watching the display and waiting. Finally the SO was “PO’d” and decided to just leave, as we’d been there nearly an hour and a half. As soon as she disconnected, it displayed 100%

And please all feel free to leave rude comments and tell me how I posTed in the wrong plac, et all. Trust me, I have looked, searched and I’m over it.

Carry on

Does your M3SR have LFP cells? I thought the current ones do, if so 100% is the recommended charge.

 

[n2mb_racing]

Take two identical Teslas.

Charge one at 240V/48A. Let's say it takes about one hour to charge. During that one hour, the vehicle is awake. Most of the power goes into the battery, but some is used for other purposes.

Charge the other at 240V/16A. That one takes about three hours to charge. The same amount of power goes into the battery, but over a longer period of time requiring the vehicle to be awake for three hours instead of one hour, so the power required for other purposes just increased by 3x.

Charging at 240V/16A is less efficient than charging at 240V/48A. Depending on how much you drive and what you pay for electricity, this may amount to less than $1 per month or it may cost several dollars per month, but the fact remains that slower charging is less efficient.

Yes. Someone did this test a while ago, and it was pretty diminishing returns above 30A. I agree, 240V 16A is lower. I just looked at Tessie and got:

81% efficiency at 108V 12A
92% efficiency at 240V 16A
97% efficiency at 240V 32A

I couldn't find any at 48A to compare, but I doubt that much better. I also think the 16A number was artificially low because I'm charging with Sentry mode on for that one, and sentry mode off for the 32A one.

Anyway, I've thought about getting the wall connector as well, but I stuck with the NEMA 14-50 because I'm pretty sure my next car won't be a Tesla. I've brought my Plaid in for service 10 times so far and it is still broken.

 

[n2mb_racing]

I think we should take the Cooper / Eaton 5754n off this list. I just replaced mine after 5 years. It kept overheating, despite re-stripping the wires, re-torquing, etc. I replaced it with the Bryant 9450FR and the overheating stopped.

 

[zroger73]

Anyway, I've thought about getting the wall connector as well, but I stuck with the NEMA 14-50 because I'm pretty sure my next car won't be a Tesla. I've brought my Plaid in for service 10 times so far and it is still broken.

Ford, GM, Volvo, Polestar, and Rivian will be using Tesla's connector in less than two years. Hyundai, Stellantis, and Volkswagen are considering it. ChargePoint and Electrify America will be adding Tesla's connector. Most charger manufacturers will be using it as well. The SAE will be codifying it as a standard. It would be foolish at this point for an automaker not to adopt Tesla's NACS connector.

It is a safe bet that a Tesla Wall Connector purchased today will charge a non-Tesla EV in the future. Porsche may be one of the last holdouts.

 

[zroger73]

Does your M3SR have LFP cells? I thought the current ones do, if so 100% is the recommended charge.

Good point, I forgot about that.

@Carsmak...

To determine if your vehicle is equipped with an LFP battery, navigate to Controls > Software > Additional Vehicle Information. If your vehicle is equipped with an LFP battery, "High Voltage Battery type: Lithium Iron Phosphate" is listed. If your vehicle does not have an LFP battery, the high voltage Battery type is not specified.

If your vehicle is equipped with an LFP Battery, Tesla recommends that you keep your charge limit set to 100%, even for daily use, and that you also fully charge to 100% at least once per week.

More info here:

Model 3 Owner's Manual | Tesla

Learn about your vehicle’s battery and battery best practices.

www.tesla.com