Why 60A and 100A Wall Connector charges at the same speed

[CaliM3]

I am about to received my vin #s and am planning on purchasing a WC, but reading their charging speed puzzled me Wall Connector

The charging speed increases with the size of breaker steadily from 15 amps to 60 amps. Why does the charging speed remain the same across the board from 60 amps to 100 amps? Did Tesla software block the charging speed from 60A to 100A? Why?

 

[cwerdna]

Please see Onboard Charger and Three Things Determine EV Charge Time.

The bottleneck is the car's on-board charger and the vehicle acceptance rate.

240 volts * 48 amps = 11,520 watts = 11.52 kW

With a 100 amp circuit, the max safe sustained load is 80 amps. 240 volts * 80 amps = 19,200 watts = 19.2 kW. Unfortunately, Tesla no longer sells vehicles in the US w/80 amps of OBC.

 

[ammulder]

I think the reason you'd get a line > 60 Amps is if you plan to install two chargers. You could put two wall units on a 100A line and get great simultaneous charging speeds on both, but if only one was in use it would be no better than a 60A line.

 

[dmurphy]

One very common misconception is that the “thing on the wall” or “thing you plug in” is the charger. It isn’t. The charger is actually part of the car.

What you’re installing is just a power cord, really.

So, the onboard charger in the Model 3 LR tops out at drawing 48 amps. Even if you give it a 200 amp power cord, it’s still only capable of using 48 amps. (By code, you can only draw a continuous load that’s 80% or breaker capacity. That’s why you use a 60amp breaker for a 48amp load.)

Same as your washing machine - just because it’s plugged into a 20 amp capable outlet, doesn’t mean it’s going to use 20 amps ....

All that said, I have the Wall Connector installed on the outside wall of my garage and love waking up every single day with a “full tank” .... never having to worry about refueling before work or anything like that.

 

[ammulder]

All that said, I have the Wall Connector installed on the outside wall of my garage and love waking up every single day with a “full tank” .... never having to worry about refueling before work or anything like that.

I had convinced myself to get a NEMA 14-50 because I could put an extension cord on it and charge even when parked in the street (otherwise, I'd park at the bottom of the driveway; the garage and main driveway area have sort of been taken over by kids.) Then we had a rainy night, and I was thinking that the wall adapter is weatherproof but an extension cord isn't. So my current thinking is get a wall adapter mounted on the outside of the garage; it will reach far enough down the driveway. If I'm stuck at the street for some reason I can still get 5 miles/hour with an extension cord to the 120V outlet on the outside of the house, weather permitting.

Of course, the electrician estimate was due Wednesday and I'm still waiting... so I've gotten familiar with that 120V outlet for now.

 

[Casmium]

If you get the NEMA 14-50 wall connector you can get a NEMA 14-50 extension cord if you install a NEMA 14-50 outlet

 

[ammulder]

If you get the NEMA 14-50 wall connector you can get a NEMA 14-50 extension cord if you install a NEMA 14-50 outlet

Right; my concern was leaving the mobile adapter plugged into a 14-50 extension cord outside/overnight when there's bad weather around. The join between the mobile adapter and extension cord would be exposed to the elements, and that seemed a bit more sketchy when the wall adapter is supposed to be essentially weatherproof. I could get both the 14-50 and wall unit, but that just seems like overkill. It shouldn't be THAT often I need to charge out at the street.

 

[dmurphy]

I had convinced myself to get a NEMA 14-50 because I could put an extension cord on it and charge even when parked in the street (otherwise, I'd park at the bottom of the driveway; the garage and main driveway area have sort of been taken over by kids.) Then we had a rainy night, and I was thinking that the wall adapter is weatherproof but an extension cord isn't. So my current thinking is get a wall adapter mounted on the outside of the garage; it will reach far enough down the driveway. If I'm stuck at the street for some reason I can still get 5 miles/hour with an extension cord to the 120V outlet on the outside of the house, weather permitting.

Of course, the electrician estimate was due Wednesday and I'm still waiting... so I've gotten familiar with that 120V outlet for now.

My thinking exactly. My garage can’t fit a vehicle (previous homeowners carved the back of the garage out into a sun porch and now it’s not deep enough to fit a vehicle!) so I need to park in the driveway.

The next issue was the Spousal Directive that the Connector not be seen on the front of the home ....

So I went with the Wall Connector mounted to the side of our home, behind the gate. I chose the 24’ cable length so I can park either nose in or nose out to the garage.

The install was done so nicely that if, for some oddball reason, I wanted to replace the HPWC with an outdoor enclosure an a 14-50 receptacle (or something like a Clippercreek EVSE) - I’d be fine doing so.

But here’s how it looks from the front - the HPWC is behind that fence gate. I passed the cable between the fence post and the siding, and mounted a little 3D printed block on the side of the fence post for hanging the Connector. So far that hasn’t put me in violation of the Spousal Directive.

All said, this has been a GREAT setup so far. Ask me again in February when we have ice and snow on the ground, but for now, it was well, well worth the couple extra bucks for the HPWC. Given that the HPWC is what they use for all the destination chargers, it’s built for bad weather. I appreciate that.

 

[Wennfred]

Also many people call the Wall Connector a Charger, it’s not.... is a EVSE which is a Electric Vehicle Service Equipment, pretty much as someone called it, and electric cord... the onboard “charger” is located in the car.

Fred

 

[ngogas]

Model 3 taps out at 48 amp. Use 100 amp if you plan to have two charging units. A 50 amp breaker would work for single as well.

 

[Jffurlan]

Also good to note UMC only charges up to 32A, so if you want the 48A charge rate The Wall Connector is a must.

Was using the 110V until yesterday when my electrical upgrade got approved by the city. Pulling 8kW vs 1kW is soooo nice.

 

[M3BlueGeorgia]

I am about to received my vin #s and am planning on purchasing a WC, but reading their charging speed puzzled me Wall Connector

The charging speed increases with the size of breaker steadily from 15 amps to 60 amps. Why does the charging speed remain the same across the board from 60 amps to 100 amps? Did Tesla software block the charging speed from 60A to 100A? Why?

It depends on your variant of Model 3.

The LR variants can charge on a 240v supply at a maximum of 48A continuous == 60A
The MR and SR+ variants are limited to 32A continuous == 40A
No Model 3 can support over 60A.

The Mobile Connector is limited to 32A regardless, but the Wall Charger on a LR variant can charge at up to 48A.

BTW: If installing a Wall Charger, there's no harm in supplying above 60A, but, for Model 3, no benefit either.

Edit: Fix difference between rated and continuous amperage.

 

[SammichLover]

The LR variants can charge on a 240v supply at a maximum of 48A.
The MR and SR+ variants are limited to 32A.
No Model 3 can support 60A.

You install a 60A breaker to reliably provide 48A of current. So the 60A here talked about here is the breaker size, not the actual current provided.

Yes, this is an endless source of confusion. Especially since a 40A breaker supports up to 32A to your car, while a 50A breaker is good for supplying 40A to your vehicle. These two different 40's get confused all the time.

 

[ammulder]

BTW: If installing a Wall Charger, there's no harm in supplying above 48A, but, for Model 3, no benefit either.

I'm going to object to your wording, if not your idea. Since you're not supposed to draw more than 80% of the rated power on an ongoing basis, you need a 60A line & breaker ("supply") to achieve the maximum 48A charge speed. If you figured you wanted 48A so you installed a 50A breaker and 50A capable wire, you'd need to set the HPWC for a less-than-maximum 40A charge speed.

(This is all assuming a LR/AWD/P3D)

 

[CaliM3]

Thank you all for your reply! I get a better picture now. I wonder if the On Board Charger is something easily up-gradable...in the future. What I would really like to see is someday I could use the DC generated by my solar panel to directly charge my car.

 

[SammichLover]

I wonder if the On Board Charger is something easily up-gradable...in the future.

Very unlikely, with the Model 3 it is bundled into you battery pack. I understand that's a pretty tight design, so it'd be a lot of work to create an aftermarket upgrade solution.

What I would really like to see is someday I could use the DC generated by my solar panel to directly charge my car.

This would practically speaking require Tesla publishing their SC specs. Rumours are that at least one hacker has reverse engineered the SC handshaking enough to recharge at a SC with a non-official vehicle, so it might be something really out there for a very high skill DIY. However that's difficult to base a publicly sold product around and also a slightly different thing.

Once you have the handshaking down; Solar panels already natively produce DC current, so you just need a DC-to-DC convertor to step it up and control it at the required 350V - 400V volts. There is already gear sold that does that, as there are quasi-turnkey solutions that use similar 3rd party Li battery packs for direct storage of DC output from solar panels.