Just use a mobile charger with 5-15 (at least initially)?

[Brian_2024]

I'm planning to order a MYLR in a month and was planning to put a wall charger in before I get the car but now wondering if it's even needed. My garage has just 5-15 outlets and one 5-20 outlet, so I think I'll be able to get 3-4 mph of charging as is. I don't drive a lot - maybe average 20-30 miles a day and the car will be in the garage most of the day.

Some minor downsides to the wall charger is the cost (maybe $1k more after rebate), the electrician would run PVC pipe in the garage along the wall and ceiling (not a big deal but could be an eye sore) and I may move in a year or two.

Other than charging speed, is there anything else to consider?

Should I be fine just getting a mobile charger for a 5-15 circuit and waiting to do a 50amp wall charger install?

 

[jcanoe]

You would be OK using either the 5-15 receptacle (120V, 12A when charging) or the 5-20 receptacle (120V, 16A when charging.) If you drive 20 to 30 miles per day for your commute that is all you would need. Don't let anyone sell you on needing a 240V, 50A or 60A charging circuit. (It is true that charging at 120V is ~15% less efficient overall than charging at 240V, but it could take years to recoup the cost of installing a 240V circuit.)

As noted by @Tronguy, in cold weather the Tesla Model Y will use some energy from the high voltage battery to warm the battery as needed (probably not an issue in NC as it would be in MN or Canada in winter.) The result is that the time needed to charge would be slightly longer in winter. (All power used to warm or cool the battery pack is taken from the battery pack, then replenished while charging.)

The 5-15 receptacle, 120V and 12A is good for adding ~4 to 5 miles of driving range to the battery per hour. The 5-20 receptacle, 120V and 16A is good for adding ~7 miles of driving range to the battery per hour. (You can purchase the Tesla 5-20 power plug adapter for the Tesla Mobile Connector online at the Tesla store; Tesla.com.

 

[Tronguy]

Only issue has to do with cold. If you’re in a climate where the temps get below 40F or do, the car will attempt to warm the battery by one means or another before the charge rate picks up. I, personally, have seen the car charge at 1 mph or less when the ambient was around 25F or so. 1.44kW only gets one so far.

At 240 VAC, any current, there’s enough power to heat the battery and charge. As a relatively cheap way out, it’s possible to convert that NEMA5-20 to two hots and a ground, and thus get 3.84kW, enough to charge when it’s cold.

 

[E90alex]

As a relatively cheap way out, it’s possible to convert that NEMA5-20 to two hots and a ground, and thus get 3.84kW, enough to charge when it’s cold.

This would be a great option if the 5-20 is a dedicated circuit. If so, it should be able to easily and inexpensively convert to a 240V 6-20.

 

[davewill]

Another issue is the poor wiring methods that are sometimes used for residential 5-15 outlets. It's common to see the circuit using backstabbed wires daisy-chained through multiple receptacles. If I were relying on one day in and day out, I'd want to make sure the wiring was sound.

 

[Cosmacelf]

It does cost more to charge at 120v. The car’s internal voltage converter is much more efficient at 240V, and the car uses typically 250W constantly while charging, so 120V charging has a constant fairly high overhead as a percentage of juice going in.

That said, 120V charging works for some people.

Check out the calculator at the bottom of this page to see how much extra 120V charging is in cost. CarCharging.us

 

[EdJack]

Is the 5-20 a dedicated circuit? Or is it daisy chained to other outlets in the Kitchen/Laundry Room, etc.?

If dedicated, then you could get the NEMA 5-20 pigtail from Tesla for the Mobile Connector. I have both 5-15 and 5-20 and the 5-20 gives a couple more miles an hour, which is a noticeable difference. But the Mobile Connector I carry in the trunk for emergencies, and have never used it other than to test it when I bought it.

I would recommend a Wall Connector, if at all possible. Also, if you are running conduit inside the garage, I would also recommend using 3/4" EMT (not PVC). As EMT is more durable, offers better physical protection, won't crush/crack like PVC, better protection against fire/pests/temperate, won't sag like PVC, and the entire length of EMT can be used as a ground.

 

[exxxviii]

I'm planning to order a MYLR in a month and was planning to put a wall charger in before I get the car but now wondering if it's even needed. My garage has just 5-15 outlets and one 5-20 outlet, so I think I'll be able to get 3-4 mph of charging as is. I don't drive a lot - maybe average 20-30 miles a day and the car will be in the garage most of the day.

Some minor downsides to the wall charger is the cost (maybe $1k more after rebate), the electrician would run PVC pipe in the garage along the wall and ceiling (not a big deal but could be an eye sore) and I may move in a year or two.

Other than charging speed, is there anything else to consider?

Should I be fine just getting a mobile charger for a 5-15 circuit and waiting to do a 50amp wall charger install?

I did this for a month or so, and it was very tedious. Charging it 110V/12A is 1.3 kW and super slow. So, you have to charge every day, since you will only be able to add around 50 miles/day or less most days. You can keep up, but it just needs to always be plugged in.

 

[Brian_2024]

Thanks all. Good to know and a lot to learn. I'm having an electrician come out and give an estimate this afternoon so will ask about different options. It seems like going with 240v will be worth it, just not sure yet which wiring I'll do.

Is the 5-20 a dedicated circuit? Or is it daisy chained to other outlets in the Kitchen/Laundry Room, etc.?

I just checked my breaker box and there's a single 15amp breaker to all the outlets (about 4 "double" 5-15 and a single 5-20) in the garage and 2 receptacles outside.

 

[Brian_2024]

I did this for a month or so, and it was very tedious. Charging it 110V/12A is 1.3 kW and super slow. So, you have to charge every day, since you will only be able to add around 50 miles/day or less most days. You can keep up, but it just needs to always be plugged in.

Isn't charging everyday recommended? I agree, it would be nice not to

 

[exxxviii]

Isn't charging everyday recommended? I agree, it would be nice not to

Yes, but I prefer to charge as-needed. I am not driving a lot now, so I prefer to charge about once/week when the battery gets below 50%. I don't like having the cord draped in the garage all the time.

 

[jcanoe]

Plugging in daily, at least once per day, is recommended. However, depending on how many miles you drive you may find that you can skip a day, charge 3 to 4 times per week. Your charging needs will be greater in winter, with perhaps 20% to 30% more energy used in winter. This is due to the general lower efficiency in colder temperatures and warming the passenger cabin for comfort. Battery warming will also take place automatically as needed.

 

[davewill]

Isn't charging everyday recommended? I agree, it would be nice not to

Really any charging regimen that keeps the battery level in a useful range will do. Charging every day helps keep things like cabin overheat protection or sentry mode from being much of a concern, and gives you maximum range every morning.

 

[Tronguy]

Thanks all. Good to know and a lot to learn. I'm having an electrician come out and give an estimate this afternoon so will ask about different options. It seems like going with 240v will be worth it, just not sure yet which wiring I'll do.


I just checked my breaker box and there's a single 15amp breaker to all the outlets (about 4 "double" 5-15 and a single 5-20) in the garage and 2 receptacles outside.

So, starting from the top:

• Given a choice, sticking in a wall connector (brand doesn't matter, but Tesla's, weirdly enough, are cheaper than the competition's) at 48A and 240 will be (a) convenient, (b) future proofing, and (c) solve your charging issues, period. If all the poles on the ski slope are aligned (doesn't always happen) this'll set you back $750-$1000; but consider it part of the cost of having a BEV.
• A common penny wise, pound-foolish game, which I'm telling you about so you won't get snagged, is to put in something like a NEMA14-50 and use the Mobile Connector. You'll get 32A out of that, but the problems are (a) a good NEMA14-50 socket that won't die relatively quickly is expensive, and (b) almost all installs that go into a garage these days require a GFI socket or breaker, and those, too, are expensive. Wall Connectors don't need those, so it turns out that going for a hard-wired wall connector is either a wash or cheaper, and, in any case, less trouble going forward.
• If you're going for a new circuit (that's what electricians can do for you) there'll be two limitations right off the bat:
  1. A 240 breaker is a dual breaker, taking up two slots in your breaker panel. There would need to be room. Many older houses don't have the room (60A or 100A service with a limited number of slots). Many newer ones do. This can be fixed with a sub-panel, but an electrician would know more.
  2. The house has to have the capacity. An electrician will do the equivalent of counting on toes (Load analysis), working out how much of an additional load the house panel can handle. A licensed (not fly by night) electrician won't put in a circuit if it's a-gonna pop the mains. At my place, relatively new construction and a 200A panel meant that all that wasn't a problem, and there was plenty of room for another breaker. This could mean simply not doing 48A; 32A might be all that your house can handle on the BEV.
• If you're lucky, the breaker panel's near or adjacent to the garage and life is good. If not, well, there's been stories about having to go through stone walls, or around the outside of the house. Again, more expense, if needed.
• Many states of which I'm aware are Really Big on pushing people to get BEVs. In NJ, for example, there are subsidies for increasing the amperage of the drop from the power pole, subsidies for installing hardware for BEV charging, and cheaper rates for BEV charging, especially at off-hours. In responding to other posts over the years, I'm aware that VA, DE, MA, and, I think, NY all have these; in fact, I don't think there's a state that I've checked that doesn't, but there probably are some. So, haul out your Google skills and look to see if your state does that, preferably before the electrician shows.
• Tesla, on their web site, keeps a list of Tesla-approved electricians. Some have said these people are more expensive; I dunno, I used one of them back in 2018 and they did a decent job. What I haveheard about are electricians that, when faced with a BEV installation, make mistakes. There's two main ones of which I'm aware:
  1. Using the wrong gauge and type of wire. If you go for 48A, please note that this calls for a 60A circuit (Max continuous heavy load on a circuit can only be 80% of that circuit's rating; that's why your 15A circuit can only charge at 12A, or your 20A circuit at 16A. 80% of 60A is 48A.) The occasional electrician will put in a gauge wire for 48A or 50A and tell you you're good to go.. but you aren't. Further, everything about wire gauges and wire types is about the Heat. Power dissipation goes as Amps*Amps*Resistance (note the square in there), and that heat has to go somewhere. If the wire is over-insulated in the heat sense, it can get hot enough to singe and melt the insulation, and That Would Be Bad. So, this isn't your typical run out to Home Depot and getting some garden-variety ROMEX. Real electricians often wire up lots of electric stoves and kinda think that this is one of them.. but it ain't. When nudged, the light dawns (they're not, generally, idiots), but it's much better to have a lit light early in the planning rather than later: Copper is expensive.
  2. Along those lines: Get the job permitted. The more fly-by-night types will try and skip that step, but this is one you don't want to skip. Because mistakes can burn the house down, and electrical building inspectors are All About Preventing That. Even if you've got a good electrician, it's a fact of life: People Make Mistakes. Another pair of eyes looking at stuff would be a Good Thing.
• If you get an electrician involved: This is a contracting job. The usual rules apply. Unless the one you're using is some kind of personal friend (not implausible, my across-the-street neighbor did the electrical for a kitchen reno many years ago), do the usual: Get more than one quote and talk to them. Check to make sure that the State you live in has them listed as being licensed and insured. And, as usual, they'll typically bid different amounts and all that. FWIW, the guys who did my place didn't even show up: I just took lots of pictures, including the interior of the breaker box, the garage, and where I wanted the TWC to go, and that was sufficient for the purpose. Load analysis and all.

Hope all this helps.

 

[3sr+buyer]

• Given a choice, sticking in a wall connector (brand doesn't matter, but Tesla's, weirdly enough, are cheaper than the competition's) at 48A and 240 will be (a) convenient, (b) future proofing, and (c) solve your charging issues, period. If all the poles on the ski slope are aligned (doesn't always happen) this'll set you back $750-$1000; but consider it part of the cost of having a BEV.
• A common penny wise, pound-foolish game, which I'm telling you about so you won't get snagged, is to put in something like a NEMA14-50 and use the Mobile Connector. You'll get 32A out of that, but the problems are (a) a good NEMA14-50 socket that won't die relatively quickly is expensive, and (b) almost all installs that go into a garage these days require a GFI socket or breaker, and those, too, are expensive. Wall Connectors don't need those, so it turns out that going for a hard-wired wall connector is either a wash or cheaper, and, in any case, less trouble going forward.

You probably mean to make the distinction between hard wired versus plug in EVSEs.

While Tesla offers hard wired wall mount (Wall Connector) and portable plug in (Mobile Connector) EVSEs, other brands do offer plug in wall mount EVSEs. However, these are probably less desirable than either hard wired wall mount or portable plug in EVSEs for most cases.

 

[Brian_2024]

Quick update: A couple of the licensed electricians said they could add the circuit to the 100 amp panel in my garage and quoted around $1,500. The last electrician said that would trip the breaker (I was wondering the same), said they'd have to update the panel to the outside of the house and quoted $6,800

Hmmm, I know I'm not paying $6,800 to have a charger put in, but am wondering if that electrician was correct....say charging the Tesla, running the stove and running the dryer would be too much for 100 amp panel?

 

[jcanoe]

Quick update: A couple of the licensed electricians said they could add the circuit to the 100 amp panel in my garage and quoted around $1,500. The last electrician said that would trip the breaker (I was wondering the same), said they'd have to update the panel to the outside of the house and quoted $6,800

Hmmm, I know I'm not paying $6,800 to have a charger put in, but am wondering if that electrician was correct....say charging the Tesla, running the stove and running the dryer would be too much for 100 amp panel?

What is the amperage of the new 240V circuit you asked for in the quote?

 

[Mike728]

Quick update: A couple of the licensed electricians said they could add the circuit to the 100 amp panel in my garage and quoted around $1,500. The last electrician said that would trip the breaker (I was wondering the same), said they'd have to update the panel to the outside of the house and quoted $6,800

Hmmm, I know I'm not paying $6,800 to have a charger put in, but am wondering if that electrician was correct....say charging the Tesla, running the stove and running the dryer would be too much for 100 amp panel?

I was quoted over $10k by one company for that. I found out from another, that there's a current sensing intermediate panel that will shut off the charger if current goes above 80A, so the upgrade wasn't needed. That same company quoted me $3k for the panel upgrade, so I'm going with that instead. Quotes can be all over the place.

 

[exxxviii]

Quick update: A couple of the licensed electricians said they could add the circuit to the 100 amp panel in my garage and quoted around $1,500. The last electrician said that would trip the breaker (I was wondering the same), said they'd have to update the panel to the outside of the house and quoted $6,800

Hmmm, I know I'm not paying $6,800 to have a charger put in, but am wondering if that electrician was correct....say charging the Tesla, running the stove and running the dryer would be too much for 100 amp panel?

Is the 100A panel in the garage the sole panel for the home? If it is a sub-panel, what is the capacity of your home's main panel?

If you have a 50 A oven circuit and a 30 A dryer circuit, then yeah, adding another 50 A charging circuit is probably too much.

 

[3sr+buyer]

Hmmm, I know I'm not paying $6,800 to have a charger put in, but am wondering if that electrician was correct....say charging the Tesla, running the stove and running the dryer would be too much for 100 amp panel?

Electric stoves are commonly on 50A circuits. Electric dryers are commonly on 30A circuits. That means that a transient 80A load or continuous 64A load could occur if both are being used at the same time. This leaves rather little headroom for EV charging (32-48A on a 40-60A circuit) if the main panel is 100A.