120v at 20amp charming Model 3

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#1
Hi Everyone,

I live in a condo and my HOA will not allow me to increase the power to my person outlet in my parking spot. Currently I have a single dedicated receptacle that is running 120v at 20 amps to a dedicated 20 amp breaker.

I’m wondering how many miles per hour of charge I would get for a model 3? My calculations give me somewhere between 6-7 mph even at only 80% efficiency (16amps) this is based on 1.9 kw and a watt/rate consumption of 250 per mile as the model 3 is more efficient.


Can someone please verify my math is correct. Tesla charges show that using a Nema 5-20 at 120v and 20amp only gives the model 3 a charging rate of 4 miles per hour.
 

MelindaV

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garsh

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#3
...even at only 80% efficiency (16amps)...
Just to clarify - this isn't efficiency. It's a percentage of peak capacity. Circuit breaker (and wiring) ratings are for usage spikes, such as starting a compressor. When you're continuously pulling that much current, you're limited to 80% of that peak capacity. That's why you're limited to drawing 16 amps from a 20amp circuit when charging a car.

Tesla has a chart on this page (scroll down a bit) that gives charging rates for various home hookups. For a 240v, 20 amp breaker (16 amps max current), they estimate 15 miles for every hour of charging. So for 120v, it should be about half, so 7.5 miles for every hour. So your estimate sounds pretty good.
 

jsmay311

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#5
Tesla has a chart on this page (scroll down a bit) that gives charging rates for various home hookups. For a 240v, 20 amp breaker (16 amps max current), they estimate 15 miles for every hour of charging. So for 120v, it should be about half, so 7.5 miles for every hour. So your estimate sounds pretty good.
Scroll down a bit further to find the 120V charging rates:

upload_2018-5-30_16-27-14.png
upload_2018-5-30_16-27-35.png

120V charging is less efficient than 240V charging -- and apparently especially so with Teslas. So you're not going to charge as fast as 50% of the 240V charge rate for an equivalent amperage.

Granted, these numbers shown above (3mph for 120V;12A and 4mph for 120V;16A) are likely conservative when charging in moderate temperatures.

Here's a guy who measured his 120V 12A charging on his Model 3 and got ~4.25mph.
https://teslamotorsclub.com/tmc/posts/2774531/
 

iluvmacs

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#6
There's a good, elegant solution here that hopefully won't upset your HOA. Since the outlet is on a dedicated breaker, have it changed to 240V (2-pole breaker, still 20A) with a NEMA 6-20 outlet instead. No wiring changes needed. That will double the charging rate, and only cost like $40 in materials, plus $35 for the Tesla UMC plug adapter.
 

garsh

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#7
There's a good, elegant solution here that hopefully won't upset your HOA. Since the outlet is on a dedicated breaker, have it changed to 240V (2-pole breaker, still 20A) with a NEMA 6-20 outlet instead. No wiring changes needed. That will double the charging rate, and only cost like $40 in materials, plus $35 for the Tesla UMC plug adapter.
That's a great idea to try. I'm guessing the HOA will reject the proposal. It wouldn't hurt to ask.
 

DXF

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#8
That's a great idea to try. I'm guessing the HOA will reject the proposal. It wouldn't hurt to ask.
If I had access to the panel and had modest mechanical ability with any sort of experience with home wiring, I'd be inclined to not bother them with the request. Changing the plug to 240V is very, very easy project.

EDIT: The toughest part is doing it flying under the radar as you really should throw the switch to turn off supply to the whole panel before opening to replace the breaker. The "pros" will work on a live panel if there was some need but I wouldn't recommend doing it, way to easy to slip and touch the live backplanes or the terminal on another breaker, or something. This means that the power will be out to any outlets/circuits serviced by the panel. This might cause someone concern if someone else is getting something powered by it?

I say this as someone with modest mechanical ability and decades old experience with home wiring that installed my charging station, including wiring, breaker, and the hardwired station myself. (The toughest part was the trenching. My kids aren't very good with that yet, so I was carrying the weight there even though used it as an Learning Experience for them too help me.)
 
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garsh

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If I had access to the panel and had modest mechanical ability with any sort of experience with home wiring, I'd be inclined to not bother them with the request. Changing the plug to 240V is very, very easy project.
Oh no, never do that. Always get HOA permission. Never try to circumvent their power. They'll make you pay for it later.
 

DXF

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#10
Oh no, never do that. Always get HOA permission. Never try to circumvent their power. They'll make you pay for it later.
For the first three sentences I was chuckling at the sarcasm voice I heard inside my head mouthing the words. Got to the 4th and now I'm not so sure?

Thing is I've found the opposite. Getting the HOA involved has always been more headache for me, even though it's the contractor that's handling dealing with them, rather than when I'm DIYing and just do it. I put in about 100' of fencing, no problem. I picked something that wasn't egregious, it was safety fence for the pool, it's a State legal requirement to have one, and now it's years ago so past any window where they can legally complain.

Contrast with the contractor that I'm getting to replace 2 windows insisted on getting a HOA permit, even though I said I was fine without (it's side windows, same size). Nothing but headaches, it's been delayed a few months now. At first the HOA management company was insisting on a $2000 road deposit. For a pick-up truck to drive in and out with a couple of 4'x6' windows. Then there was the quibbling about colour (because there's no real factory colour to exactly match the old windows), never mind that the side windows already are a mix-and-match of colour schemes. And they are the side windows.

Inviting busy-bodies in is a PITA, too. I've found more-so.
 

MelindaV

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#11
For the first three sentences I was chuckling at the sarcasm voice I heard inside my head mouthing the words. Got to the 4th and now I'm not so sure?

Thing is I've found the opposite. Getting the HOA involved has always been more headache for me, even though it's the contractor that's handling dealing with them, rather than when I'm DIYing and just do it. I put in about 100' of fencing, no problem. I picked something that wasn't egregious, it was safety fence for the pool, it's a State legal requirement to have one, and now it's years ago so past any window where they can legally complain.

Contrast with the contractor that I'm getting to replace 2 windows insisted on getting a HOA permit, even though I said I was fine without (it's side windows, same size). Nothing but headaches, it's been delayed a few months now. At first the HOA management company was insisting on a $2000 road deposit. For a pick-up truck to drive in and out with a couple of 4'x6' windows. Then there was the quibbling about colour (because there's no real factory colour to exactly match the old windows), never mind that the side windows already are a mix-and-match of colour schemes. And they are the side windows.

Inviting busy-bodies in is a PITA, too. I've found more-so.
might I point you to this thread, and this involved some level, if not official, of approval from the board. as an owner in the HOA, you agree to the rules. circumventing them is not really an option.
 

DXF

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#12
might I point you to this thread, and this involved some level, if not official, of approval from the board. as an owner in the HOA, you agree to the rules. circumventing them is not really an option.
1) Critical mistake was there in the 2nd sentence: "In past HOA meetings I have brought up the fact that I'm planning on installing a Tesla charger in my dedicated parking spot in our condo garage."

Did no-one get the Fight Club memo? Keep your piehole shut....or you'll have to go all the way, get official approval. (If nobody objected why didn't they ask for votes to seal it off? Oh right, because as soon as you make the choice to let busy-bodies know about something it becomes a big ordeal. *sigh* )

2) Looks more like it was backstab politics looking for a premise. Oust them from Presidency? LOL

3) Material costs here are going to be about $30, maybe, and very easily reversible (don't throw out the old receptacle & breaker). Not $1800.

EDIT: Local county/city regulations on modifications can make it more dicy. Most though have DIY options for stuff like this, that don't involve running wire.
 
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MelindaV

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1) Critical mistake was there in the 2nd sentence: "In past HOA meetings I have brought up the fact that I'm planning on installing a Tesla charger in my dedicated parking spot in our condo garage."

Did no-one get the Fight Club memo? Keep your piehole shut.

2) Looks more like it was backstab politics looking for a premise. Oust him from Presidency? LOL

3) Material costs here are going to be about $30, maybe, and very easily reversible (don't throw out the old receptacle & breaker). Not $1800.
the wiring needs to be upgraded as well... you are doubling the voltage and depending on the distance from the panel, likely need 10ga, while the existing is likely closer to 14ga- maybe 12ga. how are you running new wire and changing the breaker and receptacle for $30? or are you planning to undersize the wiring that sounds like is part of the HOA property?
 

DXF

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the wiring needs to be upgraded as well...
That is VERY unlikely if it was built in living memory. Standard NM-B wiring is rated for 600v. It's the amps that matters for the wire gauge. You just switch from tying the white neutral to the common bar to tying it into the other side of a the new double-pole breaker (it's the 2-pole type where the switches are mechanically joined some way together).

P.S. If this isn't applicable to the wiring in the house, if the wiring was somehow not rated as capable of handling 240V, I'd consider moving. Seriously.

EDIT: The voltage rating will be stamped on the sheath of the wiring if it's the bundled NM-B. If they ran the wiring singles it's probably stamped on that as well, although you will have to watch for shared commons with another circuit, which would require a separate conductor run. Fortunately that also means you'll have a raceway of some sort to run that skinny little wire down.

Now if this plug isn't alone on it's own circuit (which I'm not sure how the case would be if it was truly capable of the advertised output) then yes, wiring would be needed. Of course that also makes it far more pressing that you need to upgrade the plug.
 
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garsh

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For the first three sentences I was chuckling at the sarcasm voice I heard inside my head mouthing the words. Got to the 4th and now I'm not so sure?

Thing is I've found the opposite.
It sounds like you're in a fairly unique situation. Is your HOA board not made up of your neighbors? It seems like the majority are, and they tend to attract "busybodies" who then decide to wield their power to make sure nobody else can have nicer things than they have. If they discover that you've somehow improved your home or life without their consent, they will then make it their mission to make you pay for it.
 

DXF

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It sounds like you're in a fairly unique situation. Is your HOA board not made up of your neighbors? It seems like the majority are, and they tend to attract "busybodies" who then decide to wield their power to make sure nobody else can have nicer things than they have.
The board is made up neighbours. There's also management company they hire to handle paperwork, accounting services, etc.

There's also a separate board that reviewed applications for changes and approve them or not, and they interface with the management company. I actually sat on that board for a while.

Note that one of the current members of that 2nd board suggested to me not to bother with the widow application. Unfortunately the contractor didn't want to go that route, had already submitted, so here I am still with worn out windows and the summer heat leaking in. :rolleyes:

If they discover that you've somehow improved your home or life without their consent, they will then make it their mission to make you pay for it.
People looking to be authoritarian tools will find some other way anyway. Like an application that's somehow "different" crossing their desk. "Electric vehicles? Charging? Nobody does that, EVs are weird and owned by flaky tree huggers**. That's got to be a fire hazard! Change is scary!!!! MUST FIGHT CHANGE! HE'S BEING DIFFERENT, GET HIM!!!!!!"

** Okay, maybe the later part is not that far off. :p
 
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Brentt

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#20
I tested mine recently on 120v 20A and got 4 miles per hour. I didn't leave it plugged in for long, it might have eventually increased.