Tesla Wall charger v. Plain old NEMA 14-50

[Antfugue]

I have a NEMA 14-50 40 Amp socket in my garage. Using the long cord that came with the car, it charges my Tesla just fine. So a friend uses my code to buy a Tesla and I’m eligible to get the “Signature Wall Charger”.

Is there any charging time, economic or other benefit to using it? Or does it just look cool in my garage?

 

[anicolao]

The HWPC may or may not charge faster for you depending on whether your car is outfitted with dual chargers. Technically the charger is in the car and the HWPC is just a high power circuit to deliver juice to the charger. You will charge approximately twice as fast if your car is equipped with dual chargers, or notice no difference if not. You'll need to get an electrician to put in a 100 amp circuit, the most expensive part of which is the wiring if this is far from your electrical box.

This is worth it to me, because I often need to charge on short notice. However most seem to feel it's not worth it as they charge their vehicles overnight and there's no difference really if you have 8h to charge.

 

[Lasttoy]

You must have a 200 amp house feed or you can't install a 100 amp breaker to supply 80 amps. You must have dual chargers to accept 80 amps.
The 14.50 is on a 50 amp breaker. Single charger in car.
I have dual chargers, only found ONE 80 amp free charger in 20 states. It's here at Hilton hotel.

 

[markb1]

Dual chargers is only a thing pre-facelift on the Model S. Post-facelift, the options are 48A standard and 72A for the high amperage charger. So for newer cars, even with the low amperage 48A charger, there's a slight benefit to the wall connector vs. the old 40A mobile connector. The new mobile connector is limited to only 32A, so there's a bigger benefit compared to that.

 

[ccdisce]

You must have a 200 amp house feed or you can't install a 100 amp breaker to supply 80 amps. You must have dual chargers to accept 80 amps.
The 14.50 is on a 50 amp breaker. Single charger in car.
I have dual chargers, only found ONE 80 amp free charger in 20 states. It's here at Hilton hotel.

Is it open to the public? I may be in the area to the south to visit Dixie Crossroads and watch the Falcon Heavy fly.

There is a possibility that you may have to raise the HPWC count to 2-3 as the 2 public HPWCs in Seaside FL will charge my 100D at 72A, they may be able to get to 80A to charge your car as their installation was assited by a local business owner who owns a Tesla.

 

[mongo]

I have a NEMA 14-50 40 Amp socket in my garage. Using the long cord that came with the car, it charges my Tesla just fine. So a friend uses my code to buy a Tesla and I’m eligible to get the “Signature Wall Charger”.

Is there any charging time, economic or other benefit to using it? Or does it just look cool in my garage?

If you only replace the socket with the HPWC and keep existing wires and breakers, there will be no charge rate change. If you add new circuit, it could be faster, if vehicle and breaker panel support a higher amperage circuit (is it actually fused at 40A currently?)

The socket is not build for daily connect/ disconnect cycles, so if you take your charge cord with you often, changing to a permanently connected HPWC would be better long term. If you leave the long cord plugged in the wall all the time, this is a non issue.

The HPWC is more flush mount than a NEMA socket plus cord, so less chance of snagging it when walking by.

 

[TexasEV]

You must have a 200 amp house feed or you can't install a 100 amp breaker to supply 80 amps. You must have dual chargers to accept 80 amps.
The 14.50 is on a 50 amp breaker. Single charger in car.
I have dual chargers, only found ONE 80 amp free charger in 20 states. It's here at Hilton hotel.

Would you please stop answering every question with “dual chargers”? This is no longer 2013 or 2014. Dual chargers haven’t been a thing since the Model S facelift, and were never available on the X. It just will confuse recent and prospective owners. Chargers are either 48A or 72A single chargers.

 

[Robotpedlr]

So in summary. You are currently charging at 32amps based on your 40 amp breaker. If you move to the new Wall Connector (think HPWC is the old name). You can charge fast or much faster depending on a few factors.

Worst case if your car has a 48 amp charger you can upgrade your panel to a 60 amp breaker (important to upgrade wired to match), and directly wired to the WC, no plug. With a 60 amp set up you can get the full 48 amp charge at your car. Which is 50% faster.

Best case if you have the 72amp charger in your car you can go up to that amount assuming your panel can handle it (again wire and breaker would need to be rated for 125% of what ever your final charge goal is).

I just did the above and went with an 80 amp breaker with 4 gauge wire which results in charge rate set at 64amp which is plenty fast and the WC looks great and allows me to leave my mobile charger in the car.

 

[gregd]

Besides the possible faster charging (if your wiring is thick enough, and if you upgrade the breaker), consider that the wall charger is probably a bit more robust, both electrically and mechanically, than the mobile unit you are using now. That is probably the biggest reason to accept the upgrade. Save the wear on your mobile charger for when you really need it to be mobile.

 

[Scott_K]

You will definitely see faster charging speed with the wall connector, but as the others have pointed out, it depends what on-board charger you have installed in your Tesla. According to the Tesla website, you can expect ~29 miles/hour in ideal conditions with the NEMA 14-50 wall charger. If you have the standard 48 amp on-board charger built into your Tesla then you will get 34 miles/hour with the wall charger, which is a pretty small improvement. On the other hand, if you have the upgraded 72 amp on-board charger, then you can expect 52 miles/hour, which is almost double what you get with the mobile connector into a NEMA 14-50.

Home Charging Calculator

That said, as the other guys have pointed out it can be pretty expensive to install the wall charger, especially if you don’t currently have 200 amp service.

The way I see it: if you can afford to install it, do it. Charging performance aside, the signature wall charger looks sweet. I would love to have one of those.

 

[Antfugue]

Thanks everyone-I get it now. I have the 48 amp charger in my car, 6 gauge wire out to the garage on a 40amp breaker. Looks like I would need a 100 amp setup to get full advantage from the new wall charger. Given that I stick with the 6 gauge wire, will swapping out the 40 amp breaker for a 60 be beneficial? Could it be that easy?

Since it’s coming no matter what, I’ll use it and be cooler.

 

[mongo]

Thanks everyone-I get it now. I have the 48 amp charger in my car, 6 gauge wire out to the garage on a 40amp breaker. Looks like I would need a 100 amp setup to get full advantage from the new wall charger. Given that I stick with the 6 gauge wire, will swapping out the 40 amp breaker for a 60 be beneficial? Could it be that easy?

Since it’s coming no matter what, I’ll use it and be cooler.

A 48A charger maxes out on a 60A breaker (80% rule) which can exist on a 6 AWG copper circuit.

Confirm you have copper wires
HPWC installation instructions
Table of currents per wire size
Capacity of your panel/ service
NEC breaker sizing and wire calcs

Be safe.
Get it inspected (CYA)

 

[BerTX]

A 48A charger maxes out on a 60A breaker (80% rule) which can exist on a 6 AWG copper circuit.

Confirm you have copper wires
HPWC installation instructions
Table of currents per wire size
Capacity of your panel/ service
NEC breaker sizing and wire calcs

Be safe.
Get it inspected (CYA)

You really need to check with an electrician here.

Yes, under some circumstances a 6 AWG wire can use a 60 amp breaker, but it depends on the wire type and distance. A blanket statement that this is to code is misleading.

 

[mongo]

You really need to check with an electrician here.

Yes, under some circumstances a 6 AWG wire can use a 60 amp breaker, but it depends on the wire type and distance. A blanket statement that this is to code is misleading.

Understood. Did not say this installation was code. Did say a 60 Amp breaker supports a 48A continuous load and that a 6 AWG copper cable also supports 48A (links 2 and 4). Made no conclusions for OP. Did give links to the information needed to help determine if it is allowable. Also said to get permit/ inspected which would (hopefully) catch any violations.

Voltage drop (addressing in link 4) is a separate, use case specific issue, which comes into play if the charger throttles due to excessive drop. NEC has no requirements regarding it (as of 2004), It does recommend no more than 3% drop on branch and 5% for branch and feeder, good to not waste power.

 

[BerTX]

Understood. Did not say this installation was code. Did say a 60 Amp breaker supports a 48A continuous load and that a 6 AWG copper cable also supports 48A (links 2 and 4). Made no conclusions for OP. Did give links to the information needed to help determine if it is allowable. Also said to get permit/ inspected which would (hopefully) catch any violations.

Voltage drop (addressing in link 4) is a separate, use case specific issue, which comes into play if the charger throttles due to excessive drop. NEC has no requirements regarding it (as of 2004), It does recommend no more than 3% drop on branch and 5% for branch and feeder, good to not waste power.

Yes, you are correct. I over-reacted. The wording in your original post was accurate.

 

[mongo]

Yes, you are correct. I over-reacted. The wording in your original post was accurate.

I probably over reacted in my response also. I had tried to word the original post in an informative, but not condoning manner, so I was a little twitchy. It's a difficult line to walk when electricity can do bad things if mishandled, but is safe when done right.

 

[scaesare]

Faster charging capability aside, I prefer a Wall Charger for my home because:

- It has a longer cable
- It allows me to keep my UMC[1] in the car at all times without having to plug/unplug the UMC
- Prefer permanently wired connections for high-power applications where possible
- It has built-in cable management features
- It looks cooler

Especially for the price you are getting it at.


[1] The "M" in UMC stands for "Mobile" after all...

 

[dcmetro]

From my research and talk with Tesla folks and Electricians, 14-50 is more than ample for 75D. 100D is where you'll see the best bang for that Wall Charger, besides the look. I'm in the same boat, leaning towards 14-50, largely due to cost honestly. Wiring was quoted extra $100-$125 + $500 for the charger, so makes a difference of ~ $600 for me. What did you decide @Antfugue ?

 

[Rocky_H]

From my research and talk with Tesla folks and Electricians, 14-50 is more than ample for 75D. 100D is where you'll see the best bang for that Wall Charger, besides the look.

This kind of explanation doesn't really make sense. The speed of charging you need is based on how many miles you typically drive in a day, not on how big the battery in the car is. If your normal use is only about 20-30 miles in a day, you don't really need fast charging, no matter whether the battery in the car is a 75kWh, 100kWh, or 300kWh. If you normally drive 180 miles a day, though, yes, you really could benefit from faster charging, no matter the size of the battery in the car.

 

[dcmetro]

This kind of explanation doesn't really make sense. The speed of charging you need is based on how many miles you typically drive in a day, not on how big the battery in the car is. If your normal use is only about 20-30 miles in a day, you don't really need fast charging, no matter whether the battery in the car is a 75kWh, 100kWh, or 300kWh. If you normally drive 180 miles a day, though, yes, you really could benefit from faster charging, no matter the size of the battery in the car.

You've got a point there though most folks DON'T have a 100+ miles commute. That would be very few. For under 50-100, where majority will be, is where I stand as well.