The case for 120V 15A (12A) charging

[Doug_G]

I took delivery on Thursday and still don't have my 30A (22A) plug installed so I've just been charging with a standard household 15A(12A) and getting better than expected 8km per hour according to the iPhone app.

That's great. Just wait until winter, it'll be a lot less. If cold enough, you will get 0 km per hour.

 

[Mobsidian]

That's great. Just wait until winter, it'll be a lot less. If cold enough, you will get 0 km per hour.

I highly doubt you'd go from 8kph to 0kph in the winters in a closed garage.

 

[Doug_G]

I highly doubt you'd go from 8kph to 0kph in the winters in a closed garage.

Depends on the temperature. If your garage gets to -20 then you’ll probably get nothing. Below freezing you will get less. You can’t get away from the fact that power is required to heat the battery pack, and 120V can only give you about 1 kW. Expect no better than half speed in a closed garage.

 

[Mobsidian]

Depends on the temperature. If your garage gets to -20 then you’ll probably get nothing. Below freezing you will get less. You can’t get away from the fact that power is required to heat the battery pack, and 120V can only give you about 1 kW. Expect no better than half speed in a closed garage.

I think mine gets to 10-15C in the winters. Can it really go from 8kph to 4? That would be problematic

 

[scaesare]

i tried using my parents 120V 15A socket in their garage but I was only getting 3km/hour. I was a bit disappointed to not get 6 or 7km.

Was it quite cold?

 

[noicepls]

Depends on the temperature. If your garage gets to -20 then you’ll probably get nothing. Below freezing you will get less. You can’t get away from the fact that power is required to heat the battery pack, and 120V can only give you about 1 kW. Expect no better than half speed in a closed garage.

The battery of the Model 3 uses power from the garage plug to warm up the cold battery first. Then, once it has warmed up the battery (which even in typically unheated Ontario garages in the winter takes minutes not hours) the car then proceeds to actually charge the battery. In the actual charge phase, the battery IS fully charged up to its set limit, although the rate at which electrons move in the cold ambient temperature is slowed down in the winter, which is also the case when charging using Tesla's HPWC. There should be very little additional overnight time between winter and summer charging using the wall plug. I can say this from my personal experience charging my other EV (similarly designed cold battery charge protocol) in my unheated garage using just the wall plug for the past 4 winters and summers. BTW, when I plugged in my Model 3 into the garage wall, the screen showed input of 16A and 3kWh charge rate.

 

[Rlhm3]

Speaking of which, it is probably worth noting that the CEC requires a 20A and not a 15A outlet for EV charging since at least 2012.

Yikes! If this is true then Tesla should be mentioning this to customers since they are including that adapter.

I thought the 80% rule was good enough whereby the car draws 12A maximum on a 15A circuit.

 

[Doug_G]

The battery of the Model 3 uses power from the garage plug to warm up the cold battery first. Then, once it has warmed up the battery (which even in typically unheated Ontario garages in the winter takes minutes not hours) the car then proceeds to actually charge the battery. In the actual charge phase, the battery IS fully charged up to its set limit, although the rate at which electrons move in the cold ambient temperature is slowed down in the winter, which is also the case when charging using Tesla's HPWC. There should be very little additional overnight time between winter and summer charging using the wall plug. I can say this from my personal experience charging my other EV (similarly designed cold battery charge protocol) in my unheated garage using just the wall plug for the past 4 winters and summers. BTW, when I plugged in my Model 3 into the garage wall, the screen showed input of 16A and 3kWh charge rate.

Sorry have to disagree, based on actual experience charging my S. It can take substantial time and energy to heat the massive battery pack. There IS a big difference in summer and winter charging rates. I strongly recommend 240V charging.

 

[Hugh Mannity]

i tried using my parents 120V 15A socket in their garage but I was only getting 3km/hour. I was a bit disappointed to not get 6 or 7km.

Are you using an extension cord? That causes the current rate to drop off quite a bit

 

[DMC-Orangeville]

@Doug_G Where is your blog on winter driving? I couldn't find it on TMC.

This should be required reading for all new Tesla owners who live in areas with cold winters.
@Rlhm3 : Doug wrote the definitive blog on everything you can expect in the winter. We should all listen to him....

 

[Doug_G]

@Doug_G Where is your blog on winter driving? I couldn't find it on TMC.

It's here:

Cold Weather Driving

And there is some discussion on the topic in:

The Rules of Model S Road Tripping

 

[mknox]

Depends on the temperature. If your garage gets to -20 then you’ll probably get nothing. Below freezing you will get less. You can’t get away from the fact that power is required to heat the battery pack, and 120V can only give you about 1 kW. Expect no better than half speed in a closed garage.

Sorry have to disagree, based on actual experience charging my S. It can take substantial time and energy to heat the massive battery pack. There IS a big difference in summer and winter charging rates. I strongly recommend 240V charging.

While I largely agree, especially if you are starting with a cold soaked pack, my luck at 120 volts has been better if I started with an already warm battery. If you try to schedule your charge, and it starts in a cold garage/driveway with a cold battery, you're likely to get nothing.

 

[noicepls]

Sorry have to disagree, based on actual experience charging my S. It can take substantial time and energy to heat the massive battery pack. There IS a big difference in summer and winter charging rates. I strongly recommend 240V charging.

I think the battery tech is substantially different in the 3 compared to the S. There is a total cell-surround in the Model 3 battery ("sil gel") to transmit heat and manage cold (both in terms of dissipation and conductivity) as opposed to the S, specifically to help faster warmups and coolings. Although I plan to use the Tesla 240v HPWC for my home charging, it will be interesting to compare just the wall-plug feed too - I plan to do that this winter. While waiting for my HPWC unit to arrive and be installed, I have so far compiled a charge event metric for the car - it mostly agrees with Tesla's published rate for a 120v plug-in. What I found interesting was that AC charge rate stayed constant throughout, from the low SOC of 30% to max of 98%, which was not the case with my last DC charge at the supercharger.

 

[Doug_G]

I think the battery tech is substantially different in the 3 compared to the S. There is a total cell-surround in the Model 3 battery ("sil gel") to transmit heat and manage cold (both in terms of dissipation and conductivity) as opposed to the S, specifically to help faster warmups and coolings. Although I plan to use the Tesla 240v HPWC for my home charging, it will be interesting to compare just the wall-plug feed too - I plan to do that this winter. While waiting for my HPWC unit to arrive and be installed, I have so far compiled a charge event metric for the car - it mostly agrees with Tesla's published rate for a 120v plug-in. What I found interesting was that AC charge rate stayed constant throughout, from the low SOC of 30% to max of 98%, which was not the case with my last DC charge at the supercharger.

Can't change the laws of physics. If the battery pack has a certain thermal mass, it will take a certain amount of heat to raise its temperature a certain number of degrees. Doesn't matter how you do it, and you're limited to ~1.4 kW with a 120V outlet. All a "more efficient" system can do is make the temperature of the pack more uniform.

The one thing that will help is that the pack is smaller.

 

[Whisky]

Here's an example of a MX75D charging via a regular outlet. 22kWh added in just over 24 hours



Edit: Under ideal conditions, indoors, warm garage.

 

[noicepls]

Can't change the laws of physics..

That is effectively a cliché, not a steadfast fact. As Einstein said, we CAN change the laws of physics - first you have to know what they are and how they work - the bottleneck lies in their perceived rigidity. The laws of physics are actually quite pliant, and Quantum Computing is already helping unravel some of that mystery.

 

[Doug_G]

That is effectively a cliché, not a steadfast fact. As Einstein said, we CAN change the laws of physics - first you have to know what they are and how they work - the bottleneck lies in their perceived rigidity. The laws of physics are actually quite pliant, and Quantum Computing is already helping unravel some of that mystery.

Uh, no. You're talking about the fine details of the standard model of particle physics, and subtleties in quantum mechanics.

I'm talking about basic thermodynamics. You won't find a credible scientist on the planet who thinks you can bend the laws of thermodynamics. If our understanding of thermodynamics was that fundamentally wrong then NONE of our technology would work.

 

[noicepls]

I'm talking about basic thermodynamics

I respect your opinion, but have no interest in getting into a scientific discussion here; merely to provide personal-experience based input to the OP in regards to garage wall charging at home, so that's done. Actually, just got my HPWC installed last night, and from here onwards most of my Model 3 charging will be done on the Tesla wall connector in the garage, unless of course it stops working. In which case, there's always the 120v wall plug!

 

[Doug_G]

I respect your opinion, but have no interest in getting into a scientific discussion here; merely to provide personal-experience based input to the OP in regards to garage wall charging at home, so that's done. Actually, just got my HPWC installed last night, and from here onwards most of my Model 3 charging will be done on the Tesla wall connector in the garage, unless of course it stops working. In which case, there's always the 120v wall plug!

You cannot be describing personal experience with Model 3 winter charging, since no one in Canada has done that yet.

 

[mknox]

You cannot be describing personal experience with Model 3 winter charging, since no one in Canada has done that yet.

I was just about to jump in and say that.

In fact, in some ways it's unfortunate that so many new EV owners (Model 3) have obtained their cars at a time that can only be described as "ideal EV weather". I can just imagine what these forums are going to look like at the first sign of cold weather in the Fall.