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Many questions on home wall charger. Help appreciated.

elptxjc

Member
Dec 15, 2019
752
142
El Paso, TX
Hey gang, was 'considering' a 2021 M3 LR for my wife, but just learned that a new Tesla dealer is opening in El Paso, TX next week, so now it's official I'll buy her one (ha ha). And according to a Tesla guy in Austin, I should get it before the end of the year with 90% probability. We'll see. Waiting for a trade-in offer, but will probably just sell our car in immaculate condition privately.

Anyway, I thought the car came with a house cable/charger, but it does not. Apparently you need a $500 Tesla home charger. Now, the guy said it's better not to leave connected at home all the time, to charge it to 90%, and discharge it to about 30 to 20%, then charge it again. Before my questions, the only supercharger in town is 2 miles from my house (next to a Rudy's BBQ), and we drive about 50-80 miles a week when not traveling. With that in mind, here are my questions:
1. Is it worth/necessary to pay $500 (plus probably a hefty installation charge) for a home charger, with a supercharger 2 miles away?
2. If not, no issues always using a supercharger? Not sure if they are 75kW or 150kW, but can find out.
3. If yes, does it have to be permanently installed if you're going to use 120V? If not, meaning you can take it with you when you travel, how many hours would it take to charge an LR M3 from 30 to 90%?
4. If wall charger needs to be permanently installed, then it'd make sense to hook it up for 220V... but can you do that without having to mess up your house (drilling, etc)? I only have 1 dual outlet in the garage, which I'd still need operational.
5. If I need to drill, I'd probably install it right behind the electrical panel, which is at the end of my garage, so not a huge deal, but it'd probably cost a pretty penny. Any tips or advice would be greatly appreciated. First EV ever. Thank you.
 

Kimmi

Member
Nov 30, 2020
161
56
West Covina California
I was going to go with a NEMA 14-50 outlet, but It cost no more to install the wall connector than to install the NEMA; $1150 total charge. This was with a 70 foot run with 6 gauge copper wire. Local licensed electrician was about 40% less than (3) of the Tesla recommended ones. This way I will never forget the mobile charge cable when traveling.
 
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haggis444

Member
Oct 23, 2020
45
43
Cincinnati, OH
My thoughts:

1) For me, yes. I did not want to put a generic 240V outlet in my garage and use the mobile connector that comes with the car. Those type of outlets are not really built to be plugged/unplugged daily. But would it still last for years doing that? Probably. For convenience you could order a 2nd mobile connector but then you might as well order the HPWC. (the "charger" you mention for $500). The one note is a geneirc 240V outlet is universal and any EV could make use of it. A Tesla HPWC is Tesla only.
2) Tesla states that constantly using high powered DC will shorten the life the battery. They recommend Superchargers only when you are on trips, etc. They do recommend getting a 240V AC solution for your home.
3) Well you would probably want it that way. It is not really meant to travel, that is what the mobile connector included with the car is for. You could wire it to plug into a 240V outlet instead of hard wring it but I would not recommend that.
4) Without seeing your garage yes you probably would have to drill holes either in drywall, studs, or use external conduit. But it's a garage. And a professional electrician can make it look as nice as possible.
5) If you have a panel in your garage, and it's your main panel you are better off than a lot of us Northerners who most of us have our panels in the basement. Your wire cost would be less and the run easier. If you have a sub-panel you would really need to make sure it has enough amperage being fed by the main to see if you can actually use it.

Look if you are asking me for my opinion, get an electrician to install the HWPC hard wired. You are spending that much $$$ on a car, $500 + maybe $300 (guess) to install is a rounding error and you will not regret you did once you see how convenient it is. And final note, you don't have to use the electricians Tesla recommends. I did mine myself (not recommending that unless unless you know what you are doing). Just get a local electrician to do it. Good luck!
 
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haggis444

Member
Oct 23, 2020
45
43
Cincinnati, OH
Anyway, I thought the car came with a house cable/charger,

And sorry forgot to address this. To split hairs the "charger" is onboard the car. It converts AC to DC to store in the battery. You do get a mobile connecter as @terrywhite mentions in his great video. So whomever told you you don't get a "charger" was wrong. However the mobile connecter only comes with a connector for a standard 15A household outlet, you will get like 3-4 miles per hour charge. Painfully slow. You can buy adapters to use 240V service as I alluded to above. But you said you only drive 50-80 miles a week so you might be OK using your current setup in your garage.

And finally, you can search but Tesla does recommend you leave it plugged in whenever you are at home. So you are getting some bad info from someone.
 
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jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
8,258
9,122
Riverside Co. CA
Hey gang, was 'considering' a 2021 M3 LR for my wife, but just learned that a new Tesla dealer is opening in El Paso, TX next week, so now it's official I'll buy her one (ha ha). And according to a Tesla guy in Austin, I should get it before the end of the year with 90% probability. We'll see. Waiting for a trade-in offer, but will probably just sell our car in immaculate condition privately.

Anyway, I thought the car came with a house cable/charger, but it does not. Apparently you need a $500 Tesla home charger. Now, the guy said it's better not to leave connected at home all the time, to charge it to 90%, and discharge it to about 30 to 20%, then charge it again. Before my questions, the only supercharger in town is 2 miles from my house (next to a Rudy's BBQ), and we drive about 50-80 miles a week when not traveling. With that in mind, here are my questions:
1. Is it worth/necessary to pay $500 (plus probably a hefty installation charge) for a home charger, with a supercharger 2 miles away?
2. If not, no issues always using a supercharger? Not sure if they are 75kW or 150kW, but can find out.
3. If yes, does it have to be permanently installed if you're going to use 120V? If not, meaning you can take it with you when you travel, how many hours would it take to charge an LR M3 from 30 to 90%?
4. If wall charger needs to be permanently installed, then it'd make sense to hook it up for 220V... but can you do that without having to mess up your house (drilling, etc)? I only have 1 dual outlet in the garage, which I'd still need operational.
5. If I need to drill, I'd probably install it right behind the electrical panel, which is at the end of my garage, so not a huge deal, but it'd probably cost a pretty penny. Any tips or advice would be greatly appreciated. First EV ever. Thank you.


I didnt read the rest of the responses in the thread, but, the list of things "the guy" told you is pretty absurd, and contradicts things that tesla tells you directly in the manual.

1. The car DOES come with a mobile connector to charge the car. Its splitting hairs but the :"charger" is actually in the car (the receptacle you plug into), while the cable is basically a fancy extension cord... but the car DOES come with a mobile cord that you can plug in to charge it. Its absurd to think that someone at tesla would tell you otherwise.

2. No, you do NOT need to "run it down to 20-30% to charge it back up again". Its not a smartphone, and this contradicts what is printed in the manual that comes with the car. There is a lot of debate on what percentage to charge it to, etc, but there is NO DEBATE on whether someone "needs" to run the car down and then charge it back up. Tesla themselves tells you to leave it plugged in. Whether that is necessary or not is another story, but whatever "the guy" said there is completely wrong.

The rest of the stuff on how to connect a wall connector in your garage (you are not using the "dual outlet" thats already in your garage for that for example, others will tell you... but those things are so incorrect by "the guy" that I would not believe anything else that person said.
 
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Sophias_dad

Supporting Member
Jul 29, 2018
1,054
953
Massachusetts
1) The universal mobile connector comes with the car. It includes a 5-15 outlet (usual 120V AC plug). Other plugs, up to and including a 14-50 240V plug are available, for $35 each.
2) The supercharger isn't a big deal. 50-80 miles a week can EASILY be covered with the standard 120V connection on the UMC(somewhere around 5mi/hr), no need for a new outlet or wall connector. Heck, charge for 6 hours twice a week and you got it covered.
3) The UMC is usually brought on roadtrips. If you have a particular place you know you'll want to charge(see www.plugshare.com) you'll want to buy the correct adapter. Also notable is there's a J1772 adapter included with the car, which covers many public charge stations(chargepoint et al) The charge speed at public stations is all over the place, but usually around 7kw or 25mi/hr.
4) I don't know what you mean by dual outlet. If you want more than 120V and you don't have it now, you gotta get it added. If you happen to have 20 amp service coming to the 120V outlets you have, you could get the 5-20 adapter from Tesla and get a wee bit more speed.

I wouldn't consider buying a wall connector of any sort, were I you.
 
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elptxjc

Member
Dec 15, 2019
752
142
El Paso, TX
Hey guys, thanks a million for your super helpful info. I just talked today to this guy in Austin, and he's the one training the new El Paso showroom manager, so supposedly very knowledgeable. Oh well. At any rate, I didn't want to spend all that money in a charger I feel we didn't need, so very happy to hear we can just leave the car connected to the regular 'mobile' charger when we get home. Or maybe every other day (or 3rd day), and it'd be full the next morning. And since we don't travel often, I'd just pack the cable and put it in the trunk, if we're going on a trip; no need for a second one. And the good news is I can be aggressive with the throttle when I use the car, to 'exercise' the battery a little bit. He he. Thanks again for the good news.
 
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jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
8,258
9,122
Riverside Co. CA
Hey guys, thanks a million for your super helpful info. I just talked today to this guy in Austin, and he's the one training the new El Paso showroom manager, so supposedly very knowledgeable. Oh well. At any rate, I didn't want to spend all that money in a charger I feel we didn't need, so very happy to hear we can just leave the car connected to the regular 'mobile' charger when we get home. Or maybe every other day (or 3rd day), and it'd be full the next morning. And since we don't travel often, I'd just pack the cable and put it in the trunk, if we're going on a trip; no need for a second one. And the good news is I can be aggressive with the throttle when I use the car, to 'exercise' the battery a little bit. He he. Thanks again for the good news.

There isnt any reason to "plan to plug it in every other day or every third day", especially if you are using 120.

EV charging should be on a dedicated circuit, which your current garage outlet (the one you are calling a dual outlet) almost assuredly is not. You dont need to purchase the wall connector, but you should look into adding a dedicated circuit of some sort in your garage, if possible (to plug the mobile connector into).

At a VERY minimum, you need to determine what else is on that "dual outlet" circuit in your garage. Could be a dedicated outlet for the garage (unlikely but possible) or, more likely, a shared circuit with something else. You need to know what that is, if anything, because EV charging is a continuous load. In many homes, that garage outlet is shared with other outlets on the outside of the home (like the ones people plug christmas lights into).
 

theothertom

Member
May 9, 2020
283
168
South Carolina
I used the level one (120V) charger that came with the car for about 6 months. You can gain 4-5 miles per hour with that charger, which should be sufficient for your 50-80 miles per week. (A 10 hour overnight charge will gain ~50 miles). You can always decide later if you want a level 2 (240V) charger, which is what I did.
 
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jrweiss98020

Tessa's Tesla
Jan 9, 2020
423
297
Edmonds, WA
Maybe the question is how much of the time is "when not traveling"?

In your case, using the 120V charging cord will work pretty much all the time "when not traveling". Just plug it iin ALWAYS when the car is in the garage. Set it to 80 or 85% max charge level. Let the charger keep it topped off when full, per p. 179 of the manual:

The most important way to preserve the Battery is to LEAVE YOUR VEHICLE PLUGGED IN when you are not using it.

If you plan to take a longer trip, reset the charge level to 100% to get max range. This is when it may take a lot longer than you would like. If the Supercharger is convenient, you could use that instead, but the last 10% of charge takes a relatively long time even on the Supercharger.

Over the long run, you will probably decide a 240V charging outlet will make you happier. Maybe your next birthday present?
 
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elptxjc

Member
Dec 15, 2019
752
142
El Paso, TX
EV charging should be on a dedicated circuit, which your current garage outlet (the one you are calling a dual outlet) almost assuredly is not.
I'm calling it a 'dual' outlet because you can plug 2 things there (one on top of the other). You made a great point. I need to check what else is there. I also use it to plug my charger, which I'd still need for my car, which uses up to 5A. The breakers are 20A. If the EV uses 15A, it'd probably trip with 20A, no? But if there's anything else in there, then I'd be screwed, and need a dedicated one. If I have to pay for that, then might as well make it a 220V, no?

Hey guys, so the Tesla charger is either using 15A or zero? There's no tapering of charging current, like when the battery is topped off (like 85%)? When it kicks in again, due to current draw due to cold and sitting there, does it kicks in at 15A, then 0? I'd imagine in that case the current would be less, but curious about that.

And thank you for posting that it's better to leave car connected all the time when at home. Completely opposite of that the Tesla guy told me. Geez.
 

Sophias_dad

Supporting Member
Jul 29, 2018
1,054
953
Massachusetts
I'm calling it a 'dual' outlet because you can plug 2 things there (one on top of the other). You made a great point. I need to check what else is there. I also use it to plug my charger, which I'd still need for my car, which uses up to 5A. The breakers are 20A. If the EV uses 15A, it'd probably trip with 20A, no? But if there's anything else in there, then I'd be screwed, and need a dedicated one. If I have to pay for that, then might as well make it a 220V, no?

Hey guys, so the Tesla charger is either using 15A or zero? There's no tapering of charging current, like when the battery is topped off (like 85%)? When it kicks in again, due to current draw due to cold and sitting there, does it kicks in at 15A, then 0? I'd imagine in that case the current would be less, but curious about that.

And thank you for posting that it's better to leave car connected all the time when at home. Completely opposite of that the Tesla guy told me. Geez.

Actually, EV loads are considered 'continuous', and therefore are only allowed to use 80% of the rated capacity of the circuit as a result. Plugging a Tesla into a 5-15 outlet(or a 5-20 outlet using the supplied 5-15 adapter) will have a max draw of 12 amps.

You can set in the car what the max current should be(its actually stored for future use at that particular geographic location, even!) , so if you really wanted, you could set the max to 5 amps. It will indeed(for any charging current set) ramp up and down as needed. It is constantly monitoring the voltage, and if it(the car) sees that the voltage is dropping more than is justified, it'll either slow or stop charging, and may warn you about it as well. There's a temperature sensor built into the plug/adapter that will also alert the UMC and car if it starts getting hot, and charging will be stopped.
 

elptxjc

Member
Dec 15, 2019
752
142
El Paso, TX
EV loads are considered 'continuous', and therefore are only allowed to use 80% of the rated capacity of the circuit as a result. Plugging a Tesla into a 5-15 outlet(or a 5-20 outlet using the supplied 5-15 adapter) will have a max draw of 12 amps.
Thank you very much. I just checked my circuit, and it's for the 3 garage outlets only... but it only has a 15A breaker. The problem is that one of those outlets is for the garage opener, another for the irrigation box, and the last is open, but I always leave a charger hooked up to the Bullitt there, which can draw up to 5A, so would have to disconnect that one for sure while charging the car. The question is if the opener would trip the breaker when car is charging. If yes, then it's a no-go.

By the way, I asked the guy who was in charge of construction of my house, and he said the wiring is good for 20A, but I don't like the idea of changing the breaker from 15 to 20. The immediate next breaker for bathroom outlets has a 20A breaker, so maybe he's right. Would you guys change it to 20A? But if the opener would still trip the breaker even with 20A, then it'd be a no-go for sure.

I'm going to ask an electrician how much he'd charge me to install a NEMA 14-50 outlet (Bryant, right?). The electrical box is outside, but at the rear corner of the garage. Will ask the electrician if he can drill from inside the house to the back of the electrical box, so there's no need to drill the outside of the house (I don't want to do that). And since it'd cost just a bit more to install a 220V than a 115V, might as well do a 220V 40A outlet, so the mobile charger can charge at 32A. We'd never need more than that. Just hope to find a nice cover, like the 115V ones, but not a huge deal.
 
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Sophias_dad

Supporting Member
Jul 29, 2018
1,054
953
Massachusetts
Thank you very much. I just checked my circuit, and it's for the 3 garage outlets only... but it only has a 15A breaker. The problem is that one of those outlets is for the garage opener, another for the irrigation box, and the last is open, but I always leave a charger hooked up to the Bullitt there, which can draw up to 5A, so would have to disconnect that one for sure while charging the car. The question is if the opener would trip the breaker when car is charging. If yes, then it's a no-go.

By the way, I asked the guy who was in charge of construction of my house, and he said the wiring is good for 20A, but I don't like the idea of changing the breaker from 15 to 20. The immediate next breaker for bathroom outlets has a 20A breaker, so maybe he's right. Would you guys change it to 20A? But if the opener would still trip the breaker even with 20A, then it'd be a no-go for sure.

I'm going to ask an electrician how much he'd charge me to install a NEMA 14-50 outlet (Bryant, right?). The electrical box is outside, but at the rear corner of the garage. Will ask the electrician if he can drill from inside the house to the back of the electrical box, so there's no need to drill the outside of the house (I don't want to do that). And since it'd cost just a bit more to install a 220V than a 115V, might as well do a 220V 40A outlet, so the mobile charger can charge at 32A. We'd never need more than that. Just hope to find a nice cover, like the 115V ones, but not a huge deal.

As I put in the other thread, swapping the breaker(to 20 amp) is fine if you have 12 gauge wire. You don't actually need to, most likely. I just looked at the QO square-D datasheet, and it looks like at 1.5 times the rated current, you'll get 25 seconds before it trips. (Note that this might be somewhat incorrect because they are assuming the breaker hasn't already been running near its limits for multiple hours heating up).

I'd just go with the 15 and see if you get nuisance trips. I once measured our garage door openers, and determined that the light bulbs(incandescent at the time) were taking more power in the ~5 minutes they stayed on than the opener did while opening or closing the door. Even if you get nuisance trips, you could just tell the car to charge in the middle of the night when you won't be opening or closing the door.
 

DaveRZ

Member
Nov 19, 2019
164
219
Murrieta, CA
Fully agree on investigating the cost of the 14-50 outlet. You're going to want faster charging sooner or later. Might as well get it now and not have to think about it. Obviously try to have the outlet in the most logical place (close to where the driver's side rear of the car will be) where you aren't going to be tripping over the cord all the time. These little things will matter once the new-ness of the whole thing is over and you're left wishing you'd done XYZ instead.

Even if your normal driving doesn't require you to charge all that much daily, its super-nice to be able to go on a longer trip and not worrying about charging before or after. Plus if your electric company has "off peak" rate plans, you can take advantage of that and have your higher-speed charging run during the off-peak time window.

As far as the wall charger option goes. You certainly don't need it. The UMC that comes with your car will be plenty if you feed it at least 32 amps @ 240v (which your 14-50 outlet will do). In fact, it should be able to charge your car from empty to full (which you won't be doing anyhow) in about 10 hours. HOWEVER, there are still some things to consider in favor of getting a wall connector:

  1. Some people are able to get tax breaks or credits from the IRS or state for installing EV charging equipment. I've heard on these and other forums of people having ~75% or more of their total cost offset. Consider looking into what you might be eligible for. These credits are for INSTALLED charging equipment, so an outlet doesn't count.
  2. Unplugging the UMC from the wall repeatedly causes wear on the 14-50 outlet and the UMC which will eventually need to be replaced for safety. A quality 14-50 outlet is around $80. So if you find yourself wanting to take the UMC with you frequently, you might end up buying a 2nd UMC (~$300) to keep in the car, or maybe go for the wall connector option and keep your original in the car.
  3. The wiring to the 14-50 outlet will be the same as the wiring to a wall connector (in fact, the wall connector doesn't need one of the wires - so its technically easier), so it shouldn't cost much more to install a wall connector vs installing the 14-50. So that SHOULD only leave the $500 cost of the wall connector. In fact, a 14-50 outlet will probably need a GFCI circuit breaker, which is quite pricey, whereas the wall connector doesn't require one.

Anyhow, just info to consider. In my case I ended up buying a used first generation UMC (40 amp vs 32 amp max) as my daily use connector, and keep my original in the trunk for emergencies or opportunistic charging while on the road
 
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Uncle Paul

Well-Known Member
Nov 1, 2013
6,256
6,781
Canyon Lake,CA
Your Tesla can pull large amounts of current for long periods of time when charging.

Have your electician install a 14-50 amp socket near where you want to charge and be done with it.

Charging either off a 120V circuit or exclusively using a Supercharger is inconvenient.

No need for the $500 wall connector, unless you think it looks great and can take advantage of the slightly quicker charging.

You can plug in every night, and have a 90% filled battery every morning.
 
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Rocky_H

Well-Known Member
Feb 19, 2015
6,140
7,149
Boise, ID
Wow. You got so much pathetically wrong information from that person at Tesla. And to learn that this person is training others there is really disturbing. I would report that person to their management for re-training so he stops telling potential customers false information.

No, you don't need to buy the wall connector. The mobile charging cable that the cars come with is phenomenal and can run from many types of 120V or 240V outlet types, depending on which of the swappable adapter plugs you use. These adapter plugs are $35 from Tesla's website, so you can pick an outlet to get installed and get the matching plug, and you're good to go.

I'm still using the mobile charging cord that came with my car in March 2014 as my permanent at home charging solution. It stays hanging on a hook in the wall of my garage.
 

elptxjc

Member
Dec 15, 2019
752
142
El Paso, TX
Hey gang, an update. Talked to the electrician that wired my house and a 20A breaker is a no-go; the wiring is 14 gauge, not 12. BUT, he charges me $80 to install a 220V 40A outlet back-to-back to the breaker box outside the garage, which is the way I want it (not drilling the outside of the house). The outlet would be lower than typical, but not an issue, since the cable would only get unplugged for trips on the car, which are not that often. I asked the guy for a Bryant outlet, but he said his shouldn't be an issue, since it uses bolts to secure wires. So that's exactly how I'd do it :). Oh, and he'd use 6 gauge, to install a Tesla charger in the future, if desired... but he said for safety reasons he'd use 40A breakers. Makes sense, no? If installing a Tesla charger, it'd be a matter of just replacing the breakers for 60A. Anyway, have a few more questions, based on that development:
1. No long-term additional degradation of the battery pack from charging at 32A at 220V rather than 12A at 115? Or is the ideal rate somewhere in-between, and which would it be? If we ever need 32A, we could raise it easily on the screen, right? And no issues leaving car connected all the time if it's 32A, correct? Since we don't need 32A most of the time, might as well try to maximize the life of the battery if it causes no issues for us.
2. To charge the car on its intended spot, I'd need at least 20' cable, and the new ones are only 18'. No big deal, as we can swap places, but my wife could inadvertently hit my car when carrying crap from the trunk of her car to the door, since she'd have to pass next to my car. If I can find an older cable, which I think were 24', any issues with that? I could charge up to 40A, but wouldn't use that. And does the car know at which amps to charge, or you have to tell the screen that? Thanks guys; you've been super helpful. Greatly appreciated :).
 

skgolf91

Member
Nov 21, 2019
161
81
NJ
I also live 5 mins from superchargers and another superchargers 3 mins from work. I did go twice because my free SC miles were expiring but I would never waste 20-30 mins of my life just sitting unless I was traveling.

You will be fine with 32A at home. You don't have to get the wall unit either. You can use the mobile connector with the right adapter. I'm not sure the exact length but it feels like the mobile one is longer than the wall unit. I could be wrong(probably).
 

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