SR+ owners that charge on 120V/regular outlet, real charging speeds/stats?

[The_Observer]

Hey all,

At my new job, there seems to be some regular 120V outlets around the parking structure. I was wondering maybe I could take advantage of it (ask for permission of course), despite it being slower at 120V charging. 8-9 hours of charging a day could be potentially useful to me, as my total commute is about 35 miles give or take.

Tesla does say at only 3 mph charging for 5-15 outlets, but I have also heard of people stating 4-6 mph charging. What has your experience been charging with 120V on a SR+? Is it really 3mph, or more? Thanks all.

 

[jjrandorin]

This thread has pretty much the same question, perhaps it might help:

Real World 5-15 Charging Speeds

I'm currently charging my 2022 Model 3 RWD with a regular 110v 12a NEMA 5-15 outlet. I get 8km/hr (5miles/hr), which is much more than what Tesla advertises on their website (they say 4.8km/hr). I live in a townhouse and I had an electrician take a look at my panel - he said it looks pretty...

teslamotorsclub.com

The one thing that would be important (even though I realize you mentioned it already) is to not only ask for permission at your job, but ensure you are asking someone who would know if the circuit you are plugging into can take 8-9 hours of continuous load with whatever else is on it.

 

[boneil1]

I have a 2022 model 3 rwd and routinely get 5 mph of charge on a 110v outlet. However, sometimes during mid day, early afternoon when the AC is running, and we have other appliances running, it will drop to 4 or even 3 mph.

 

[Rocky_H]

Tesla does say at only 3 mph charging for 5-15 outlets, but I have also heard of people stating 4-6 mph charging. What has your experience been charging with 120V on a SR+? Is it really 3mph, or more?

Definitely more. Here's the thing that has frustrated a lot of us for the past several years. When Tesla made the documentation tables for those charging speeds back in 2012/2013, it said 3 mph from a 5-15 outlet. But that was for the old huge heavy inefficient pig of a Model S. 3 mph was accurate. That's what I get on my 2014 Model S. When the Model 3 came along, it was smaller, lighter, and MUCH more efficient. When Tesla made the new charging tables for that, they put new numbers in it for the other kinds of charging outlets, like with 240V 30A, 40A, etc. and those numbers were different and correct, but for some unknown reason, they copied over that 3 mph number! It's blatantly wrong! It will be around 4.5 to 5, maybe even a bit above.

 

[Resist]

When first got my Model 3 I only charged it via a 120volt outlet at home for months before installing a 240volt outlet. 120 worked fine because it was charging all night while I slept and because I had 6 months of free Supercharging when I needed to go someplace and didn't have full charge from home, I'd stop and fill up.

 

[804son]

At a total commute of 35 miles, why bother. Can you charge at home? I find that much more convenient than attempting to get some free juice at work or when I'm just running errands, etc.

 

[GtiMart]

Miles per hour (kilometers per hour) as a charging unit is pretty bad, to put it mildly. As @Rocky_H indicates it actually depends on your car model / efficiency. kW is the proper unit. 5-15 provides 12A max, which at 120V is 1.44kW. Remove at least 200-250w for the car's computer and pumps and you are left with around 1.1kW to charge the battery. If you really want to know miles per hour, divide that 1.1kW (1100w) by your consumption constant per mile. On my 2020 LR AWD it's around 145wh/km so I would charge at 7.5km/h...

EDIT: But then Tesla don't tell us our battery's kWh capacity They really make it complicated for no reason.

 

[Kevy Baby]

When I charge at home, I actually get closer to 7 MPH.

At a total commute of 35 miles, why bother. Can you charge at home? I find that much more convenient than attempting to get some free juice at work or when I'm just running errands, etc.

Why charge at home where you have to pay for it when you can charge at work for free (assuming a proper circuit and permissions)? The only advantage of charging at home is not having to lug out your cable and wrap it up every day.

 

[804son]

Charging at home is .11/kwh super cheap. I can precondition my battery and cabin before I leave for work each morning and I don't have to lug around the cables to hook up or unhook at work. I LOVE the convience of it.

 

[The_Observer]

Charging at home is .11/kwh super cheap. I can precondition my battery and cabin before I leave for work each morning and I don't have to lug around the cables to hook up or unhook at work. I LOVE the convience of it.

That's a fair point for charging at home for the convenience, don't get me wrong, I am currently charging at home as well with a 240v outlet.

11 cents would sound like a dream of where I am... Here in California, even at non peak times would cost me 20cents per kwh...

 

[804son]

That's a fair point for charging at home for the convenience, don't get me wrong, I am currently charging at home as well with a 240v outlet.

11 cents would sound like a dream of where I am... Here in California, even at non peak times would cost me 20cents per kwh...

I get it, at twice the price. I would have to rethink my strategy .

 

[jjrandorin]

I get it, at twice the price. I would have to rethink my strategy .

Its actually more than twice the price out here, in general. SCE has Ev rates at about 20-21 cents a kWh, but a "time of use" rate where the rate jumps up between the "peak" time of 4pm to 9pm of either 40 cents or 54 cents a kWh.

So, trade a lower rate (but twice as much as yours) for charging your car, for a higher rate when you basically do everything else, or if you are still able to get non time of use rates, pay 28 / 36 / 45 cents a kWh based on how much you use. Thats still cheaper than $6.00 a gallon gas though. Its one of the reasons Solar is popular out here, and an EV to go with it.

Its also why people in CA tend to adopt a "if its free, its for me" philosophy, when it comes to charging an EV.

 

[804son]

Its actually more than twice the price out here, in general. SCE has Ev rates at about 20-21 cents a kWh, but a "time of use" rate where the rate jumps up between the "peak" time of 4pm to 9pm of either 40 cents or 54 cents a kWh.

So, trade a lower rate (but twice as much as yours) for charging your car, for a higher rate when you basically do everything else, or if you are still able to get non time of use rates, pay 28 / 36 / 45 cents a kWh based on how much you use. Thats still cheaper than $6.00 a gallon gas though. Its one of the reasons Solar is popular out here, and an EV to go with it.

Its also why people in CA tend to adopt a "if its free, its for me" philosophy, when it comes to charging an EV.

Yikes! I think Colorado is for me....
I would use the same strategy if our costs were that high. I'm sure we'll catch up someday. I'm not looking forward to that.

 

[Rocky_H]

My utility here in Idaho is trying to kneecap net metering. They just published a big analysis report, like 90+ pages, showing the factors and statistics and costs and such of their proposed change. What we have now is pretty good, where it nets kWh for the whole month at a time. We can generate excess into the grid during the afternoon, and charge a car overnight, and it all nets out to a + or - for the month.

What they are proposing to switch to is the ripoff hourly or instantaneous net metering, where they would pay us less than 5 cents for our generated electricity in the afternoon, but we can't net that against where we would be paying twice that rate overnight to charge an EV.

What I am going to bring up when this goes for the public meeting before the Public Utilities Commission is that in their 90+ pages of analysis, they NEVER even considered that doing that is going to be a negative pricing motivation, which is going to CAUSE people to intentionally move a lot of their heavy usage (e.g. EV charging) directly into the top peak daytime afternoons, so they can use up their own generated solar instead of getting ripped off by selling it for 4 point something cents! We don't have any cheap off peak rates at night. So where they are statistically assuming a lot of our generated electricity going into the grid that can underpay us for, that is going to go away.

 

[AlanSubie4Life]

EDIT: But then Tesla don't tell us our battery's kWh capacity

You don’t need to know that for this calculation (the charge rate).

You just need to know your charging constant* 0.955 and use that for your calculation.

You can get your charging constant (roughly) if you do a charge of over 200km/mi and swap between % and miles while still plugged in. Divide kWh added by miles added. Do a range of miles added and you’ll be able to see when it “switches” the kWh (rounded to nearest kWh) and eliminate the rounding error.

Or you can look at the position of your rated line on the energy screen and subtract 5Wh/mi (3Wh/km).

Or just divide the degradation threshold by the EPA rated miles. (Would have to have someone tell you the degradation threshold).

Or (easiest and most accurate !) go to the energy screen at high SOC, multiply projected range by recent efficiency, and divide by the rated miles remaining.

Again, have to multiply that value by 0.955 to get the actual consumption constant for displayed miles.

All four methods work and provide identical results.

For you it is ~150Wh/km (or ~143Wh/km after reduction).

 

[DrChaos]

My utility here in Idaho is trying to kneecap net metering. They just published a big analysis report, like 90+ pages, showing the factors and statistics and costs and such of their proposed change. What we have now is pretty good, where it nets kWh for the whole month at a time. We can generate excess into the grid during the afternoon, and charge a car overnight, and it all nets out to a + or - for the month.

What they are proposing to switch to is the ripoff hourly or instantaneous net metering, where they would pay us less than 5 cents for our generated electricity in the afternoon, but we can't net that against where we would be paying twice that rate overnight to charge an EV.

What I am going to bring up when this goes for the public meeting before the Public Utilities Commission is that in their 90+ pages of analysis, they NEVER even considered that doing that is going to be a negative pricing motivation, which is going to CAUSE people to intentionally move a lot of their heavy usage (e.g. EV charging) directly into the top peak daytime afternoons, so they can use up their own generated solar instead of getting ripped off by selling it for 4 point something cents! We don't have any cheap off peak rates at night. So where they are statistically assuming a lot of our generated electricity going into the grid that can underpay us for, that is going to go away.

That's not going to change the PUC or the Utility's mind.

The utility is in it for the $$$. They can probably source power at their own price cheaply, or more importantly, buy it from an unregulated corporate affiliate of the utility instead of some random homeowners.

PUC is OK as self-consumption doesn't hurt the grid.

 

[Rocky_H]

That's not going to change the PUC or the Utility's mind.

Really? If they are made aware that they may suddenly have a big unexpected shortfall of supply during the middle of peak summertime, when they would have to make that up by buying more and more energy at the most expensive prices on the open market, that will hurt them and may make them consider what to do. The thing I am hoping may actually be accomplished is that they realize they need to create a cheap night time rate that would have to go with this change in solar pricing.

The utility is in it for the $$$. They can probably source power at their own price cheaply,

No, they can't. That was in their report, that they have to spend 18 cents per kWh getting it on the energy markets. It's bad for this area, and certainly compared to the 4.9 cents they want to spend to buy it from us.

PUC is OK as self-consumption doesn't hurt the grid.

You're not seeing it, because you're looking at it as one isolated situation. You have to view it as the change from before and after. They are building their anticipated statistical models based on how people have been feeding that extra supply into the grid year after year constantly, so they have been able to meet demand and are assuming that will stay unchanged. If they make this change, and all of a sudden that extra supply they were expecting gets yanked away and disappears, that creates the same situation of having more demand than supply.

 

[davewill]

If they make this change, and all of a sudden that extra supply they were expecting gets yanked away and disappears, that creates the same situation of having more demand than supply.

Unfortunately, very few people will be able to shift a significant portion of their usage. They don't have an EV to charge in the peak sunshine hours, or even if they did, they're at work. Now, it will incentive installation of battery systems, but that will be a relatively slow process. I'm with @DrChaos on this, they would rather home solar went away entirely, and don't mind the negative incentive. After all if they have increased costs, it just justifies a rate increase to cover them.

 

[DrChaos]

Really? If they are made aware that they may suddenly have a big unexpected shortfall of supply during the middle of peak summertime, when they would have to make that up by buying more and more energy at the most expensive prices on the open market, that will hurt them and may make them consider what to do. The thing I am hoping may actually be accomplished is that they realize they need to create a cheap night time rate that would have to go with this change in solar pricing.


No, they can't. That was in their report, that they have to spend 18 cents per kWh getting it on the energy markets. It's bad for this area, and certainly compared to the 4.9 cents they want to spend to buy it from us.

You're not seeing it, because you're looking at it as one isolated situation. You have to view it as the change from before and after. They are building their anticipated statistical models based on how people have been feeding that extra supply into the grid year after year constantly, so they have been able to meet demand and are assuming that will stay unchanged. If they make this change, and all of a sudden that extra supply they were expecting gets yanked away and disappears, that creates the same situation of having more demand than supply.

I think you're making the assumption that utilities honestly want to maintain adequate supply at the lowest price. Many corporate owned ones do not. Universally they hate customer self-generation as it loses them revenue. Their goal is maximum profits for the corporate owner in light of the regulated environment.

They typically want slight shortfalls and high prices, as it justifies rate increases. They want to charge high prices selling electricity to their customers (to justify rate increases), and buying power at higher prices justifies this in the next round of rate increases, and it can often be bought from their own affiliates which benefits the ultimate shareholders.

> That was in their report, that they have to spend 18 cents per kWh getting it on the energy markets. It's bad for this area, and certainly compared to the 4.9 cents they want to spend to buy it from us.

If this were really true---and the motives of the utility aligned with the customer---then the utilities would be as eager as possible to buy electricity from homeowners at significantly more than 4.9c/kWh but less than 18. (For example in northern california recently PGE bought electricity from Tesla virtual power plant at much more than this but only temporarily). The fact that they're trying to reduce payments to customers in your area for their power instead of trying to entice them is evidence there is some other incentive happening and that they're not telling the whole truth.

They want to kill net metering because they want to kill the economics of home solar because they want the maximum possible utility bills, as they know they will have a certain profit margin no matter what.

The incentives for electricity coops and municipal utilities are different and unsurprisingly they usually have lower prices.

 

[Nogasnohands]

Your commute to work is it worth charging at work. OK most people work, home, and unless u getting off work and let's say u planning on driving 170 miles then charging at work I'd no reason