120V Charging ?

120V Charging ?

So I work from home and only drive once every 2-3 days and when I do, I only drive 30-60 miles. Could I get away with charging a Model 3 in a garage with 120V and I live in so cal so there's tons of superchargers down here. How many hours would it take to charge to 80% on 120V?

eeb9 | 2017年6月29日

Iirc, level1 charging (115v household current) charges at about five miles of range per hour.

So an 8-hour charge should give you 40 miles. Sounds doable, with an occasional top-up at a local EV charger, whether Tesla-owned or other

MKM3 | 2017年6月29日

That doesn't sound like a pretty good idea...
You'll very likely fry your electrical installation in your home, it's not supposed to handle that much load over a long time.

I'm in a comparable situation, but living in Europe, we have 220/240V, but that's the same problem. The installation will very likely melt.
You should consider installing some sort of high voltage wall box. Here it's usually 400V at 32 Ampere which delivers about 11kW. This installation would charge 60% of a supposed 75kW Model 3 battery within 4 hours.

Mozart | 2017年6月29日

Charging a Tesla on household current only draws about 12 amps. Most 120 volt receptacles are on a 20 amp breaker. Most household appliances draw more power than that. No need to worry about frying your electrical.

MKM3 | 2017年6月29日

Yeah, but you don't leave those appliances plugged and running on max for hours on end? The problem is flimsy cabeling that's not built for that charge over an extended period of time. It will heat up, and if it heats up long enough, it'll melt.

It works, but it's certainly not save. I've already fried an extension cord plug with my electrical BBQ grill after a couple of hours on max (2kW grill on 220V @ 16amp).

The 220V charger is being advertised as "emergency charger" here.

JPPTM | 2017年6月29日

MKM3--not true. You will not melt proper wiring and proper circuit breakers. Extension cords are not the same thing as a good 120V 15A US standard NEMA 5-15 receptacle. The car will derate to 12A (80% continuous draw). The UMC provided will have a nice beefy cable (made for 240V 50A use). All of us with Teslas have this and have no issues.

Lonestar10_1999 | 2017年6月29日

According to the NEC, you can continuously draw 80% current based on the breaker rating. So for a 15a breaker you can charge with 12 amps, and for a 20a breaker you can charge with 16 amps. If you exceed the NEC rate, you will likely trip the breaker before anything burns down.

MKM3 | 2017年6月29日

Okay, it may be a 120V speciality then. 240V cabeling is anything but beefy IMHO. Thermal demands may be lower at half the voltage (120V) I guess.
Permanently charging on a 220V household socket is explicitly not recomended here.

The more reason to support more DC charger standards for foreign markets.

DTsea | 2017年6月29日

Mkm3, you are correct. European household wiring is 220v to reduce current draw and wire cost.

DTsea | 2017年6月29日

Mkm3, you are correct. European household wiring is 220v to reduce current draw and wire cost. US Tesla owners can safely charge at 115V for as long as they like.

ddrmadness | 2017年6月29日

I'm going to be in a similar situation except that the car will likely be going to and from work each day about 20-25 miles each way (40-50 miles total). There is an EV charger in the parking lot at work, would I be find with using that and then topping off at home as necessary with a standard 110V outlet?

MKM3 | 2017年6月29日

Here's the situation for 220V:

I've checked some standards about 220V sockets.
A standard socket CEE 7/7 isn't - at all - designed for permanent charging, no matter how many amps (that's why my plug was melting).

There's another plug, a CEE "Camping Plug" which is specified for 16A for only up to 6 hours.

Sure, the breaker should trip, but the heat is usually generated at corroded contacts within sockets or cables. So unless you have extremely new electrical wireing or regularily swap cables and sockets you should invest in safer cabeling. EV forums here are pretty much filled with reports about molten CEE 7/7 and even Type 2 charger plugs.

I really can't imagine that it's that much different at 120V, but if that's the case, you're lucky!

MKM3 | 2017年6月29日

I'd loooove to have 120V then! :D Installing 400V@32A is quite a hefty investment.

Frank99 | 2017年6月29日

MKM3 -
You need to talk with a real electrician. If your outlet is rated for 16A, you should be able to pull 16A from it all day, every day with no concern about anything "burning up". In the US, the electric code limits constant current to 80% of the circuit breakers rating to avoid heat buildup - so the code allows you to charge your EV continuously at 12A from a standard 120V/15A outlet, or about 1.4KW. Assuming a similar current limit in Europe at 230V, you could charge at almost 3KW with no worries about anything 'burning up", as long as your wiring was installed in the last half century.

goddard11 -
Assuming a 60kwh battery, it'd theoretically take about 60kwh/1.4 kw=42 hours to fully charge (0-100%) a Model 3 using a standard 120V/15A outlet. Charging is only about 90% efficient so 48 hours is probably a good round number. Driving 60 miles, at 3 miles/kwh = 20 kwh of battery charge; that'd take 16-18 hours to recharge. If you find yourself driving more just for the sheer joy of it, you'd probably have to have an electrician install a 14-50 outlet in your garage - that'll be 240V, 50A, giving about 10KW charging. That'd do a full charge in 7 hours or so. Cost would be anywhere from $200 to $1000 depending on how far your garage is from your main circuit breaker box.

electropolishing | 2017年6月29日

Great! Thanks for the information guys.

MKM3 | 2017年6月29日

Funny thing is: that's a standard! Ask any electritian here and they'll tell you the same thing. CEE 7/7 - the plug that comes with the Tesla mobile charger here - is not designed for permanent load.

Look for IEC_60309 Blue_P.2BN.2BE.2C_6h on Wikipedia.
...according to the VDI standards consortium, this bigger, way more reliable plug is also only able to handle 220V@16A for 6 hours. Lower amps are not rated, so you may use it for a bit longer, but it will fail after a while.
You'll have to upgrade to 400V if you want something that won't break all the time.

Frank99 | 2017年6月29日

I think you'll have a hard time finding a Tesla that would be happy with 400V coming down the cable, and I don't recommend trying it.

I'm not an electrician, and I'm especially not a European electrician, but "6 hour" specs where I come from are intended to be "steady state" specs - if you can run it for 6 hours, you make the assumption that everything has reached a steady-state temperature and you could run the test for the next two weeks, months, years. These specs are not intended to be "if you do it for 8 hours, everything is going to melt". If this is actually true for European outlets, I'm sorry to hear it.

Rocky_H | 2017年6月29日

Huh. Apparently the strict electric code in the U.S. is good for something. If it's installed properly and at spec, you can count on it to do what it's supposed to do.

That's why they have the rule/distinction of the current level for short term loads versus long term (continuous) loads--to account for how much heat buildup there will be. For short term loads, like if you are running a hair dryer or a microwave or blender, or whatever, then it can use up to the full 100% of the circuit rating. For continuous loads (over 4 hours, I think) then it has to have an oversized circuit, at 125% of the constant current draw.

Coastal Cruiser. | 2017年6月29日

goddard11: That's the way I'll be charging my Model 3 here in the states. Like you, I don't drive every day. I'm not worried about overheating my circuit. I will be using a dedicated circuit on its own breaker however.

It also doesn't hurt to do a 'hand test' on any electrical cord or plug while in use. If the cord or plug or outlet is hot to the touch it's usually a sign of trouble. I haven't used the Universal Mobile Connector (UMC) cord that comes with current Tesla cars, but would be surprised if any owner reported their cable even gets warm to the touch.

MKM3 | 2017年6月29日

400V is a standard for high performance devices (like hot plates) here, because everything else is pretty much... unusable. European Teslas are fitted with different plugs that only utilize 3 phased 230V @ 16A, (~11kW), the outlet and cabeling for home user wall boxes is specified up to 22kW.
Utilizing the full potential of this standard, we get 3 phased 400V@32A public chargers at ~40kW with Type 2 plugs.

Having tons of wildly different wiring standards across all countries over the last 8 decades you can't expect every installation to be state of the art. So those standardisation guys tend to play it really, reallly safe in regards to standards and recommondations.

For example: charging an EV (BMW i3) on 230V for only 15 minutes was heating up the socket to 81°C / 178°F. Source: an e.on test

MKM3 | 2017年6月29日

@Rocky_H: exactly!! :)

Coastal Cruiser. | 2017年6月29日

One other thought goddard1. The one single thing I have seen fail in the 120V world I've lived in over the years is the venerable standard issue 120V socket. You know, the two gang outlet you plug all your stuff into. They can age, and I've replaced a few that had weak or broken metal contacts.

Since MKM3 happen to bring it up about corroded connectors, I will probably be double sure that whatever socket I plug the Model 3's cord into holds the plug nice and tight. A loose plug that falls out of the socket easily means a potential hot spot, and that it's time to pay a trip to the hardware store for a DIY $2 receptacle.

Frank99 | 2017年6月29日

Get the $10 commercial-quality receptacle. It'll last a lot longer, with a lot more margin, than the $2 receptacle.

jefjes | 2017年6月29日

National Electrical Code or NEC is written and updated regularly by fire department professionals in the US for a reason. To save lives and property by adhering to established standards when it comes to electrical installations. If you are doing any type of electrical installations, let the NEC be your bible and if you are unsure of what it is telling you, hire a professional. Don't risk your or your families lives to save a few extra bucks on something so vital. When it comes to extension cords, the length, gauge of wire in the cord, and the load it is being used for is often a source of fires since the code isn't able to control what the end user is plugging into the properly designed and protected circuit.

dsvick | 2017年6月30日


Instead of just saying it wont work why not find examples of it or back up your claims with some data not just conjecture. With all of the Tesla owners in all of the places with all of the different situations throughout Europe I'm sure there is a group of them that have had to do what you are saying they shouldn't do, I don't recall any articles about it, no one's garage has burned down for that reason that I'm aware.

Instead of running on stage like chicken little with prognostications of doom, bring us some evidence and people will listen.

MKM3 | 2017年6月30日

Well, it's in German, but the photos as well as google translate should help...
goingelectric .de/forum/bmw-i3-laden/i3-schuko-lader-hat-mir-meine-schukodose-geschmolzen-t24392.html
...if you want to charge an electric car in Europe, get CEE certified plugs.
This example is from a guy who charged his Leaf on this burnt up Schuko socket for 3 years. Due to corrosion, heat built up and fried the plug on the charger as well as the socket.

It's not prognostication of doom, it's effen physics.

MKM3 | 2017年6月30日

BTW, being cheap on the home charging infrastructure for a USD +40k car is kinda rediculous.

PhillyGal | 2017年6月30日

Yes of course it's doable and no, it won't fry anything.

But please note that the efficiency of doing so it a bit less than if you were to charge at 220 so over time, it will cost you more money.

I've gotten along great - as have many other owners - with a cheap NEMA 14-50 plug ($9 vs. $500 HPWC from Tesla) and having an electrician install it. My install was done by a friend and was just a few feet from my panel box so required minimal copper.

Iwantmy3 | 2017年6月30日

50 to 60 miles of driving each day would only need ~10-12 hours of charging (possibly less on the "3"). If the car gets plugged in each day/night, it will be able to keep up on average and the batteries size and range would simply act as a buffer. Just beware, if you take the car on a longer drive and arrive home on empty late at night, the car might not be able to charge sufficiently for you to meet your needs the next day.

High Plains Drifter | 2017年6月30日

Charging on a 120V will get old real quick. In the end, you will either install a 14-50 outlet or visit the local superchargers on a weekly basis. Hopefully, you don't choose the latter option.

milesbb | 2017年6月30日

The 120 volt circuit you use will need to be dedicated to this charging load. Multiple outlets typlicaly are on the same breaker, I believe the code allows up to 9 on the same circuit breaker. If you have a freezer or something else drawing current from this circuit you will have problems.

If The outlet you plan to use is the only connection to the breaker I recommend you convert the circuit from 120 volts to 240 volts. Very simple to do. You only need to change the outlet from 5-20 to a 6-20, new cover plate and change the circuit breaker to a two pole. Cost about $30 in parts and and hour to do. You will need a $55.00 NEMA 14-50R to 6-20P Adapter. Double your charging speed to 8-10 mph. If you live in a rental it is easy to change back to the 5-15 before you move out.

mikeysb1011 | 2017年6月30日

My electrician wants to know what size 220/240 line
Is needed. He is going to run into garage but electrical box is full and may have to upgrade system
He maybe able to piggy back on another circuit. But
Can't tell yet

mikeysb1011 | 2017年6月30日

My electrician wants to know what size 220/240 line
Is needed. He is going to run into garage but electrical box is full and may have to upgrade system
He maybe able to piggy back on another circuit. But
Can't tell yet

mikeysb1011 | 2017年6月30日

Hopefully I may receive car late 4th qtr 2017

Sandy’s 3 | 2017年6月30日

Mike. Your electrician doesn't know what size wire to run? I would find a new one. He first needs to do a load calculation on your existing service. If there is enough capacity for an additional 40, 50 or 60 amp breaker great. If not you will need a service/ panel upgrade. Eg. 100 amp to 200 amp. Then you can run the wire to a socket or Tesla wall connector. I'm in the process of upgrading my service to 200 amps. He will run 6/3 wire initially on a 40 amp breaker (Canada) to a Nema 14-50. Once i have a delivery date he will replace the 40 amp breaker with a 60 amp and the Nema 14-50 with the Tesla wall connector and I will be able to charge at 48 amps.
The 2 step process is due to EV rebates where I live. You have to have a VIN # and have bought the charging station in the province and apply within 3 months for the $1000 charger rebate.

Peanut01 | 2017年6月30日

@FLHX13 - You should be putting the 14-50 on a 50 amp breaker instead of a 60 amp. Depending on the length of your run, you may need to go with a larger diameter wire than 6AWG.

M3München | 2017年6月30日

I did a write-up this morning but the forum ate it so here I go again...

The 400V mentioned above is actually 3-phase 230V. The voltage in relation to all 3 phases (not in relation to zero) turns out to be (sqr 3 * 230V =~ 400V). There are 5 cables--3 hot (and each in its own phase) 1 neutral (return) and 1 ground/earth. My electrician said that the danger imposed by such a line is identical to that of a single-phase 230V line of the same amperage. The prevalence of this kind of electrical service is also the reason that European Teslas have a Mennekes Type 2 plug. It natively does 3-phase.

As far as the Schuko outlet overheating while charging a weirdmobile goes: for those who aren't familiar with it, Schuko is the standard household electrical outlet in Germany and much of Europe. It handles up to 250V @16A). The 16 amps is only allowed for short periods as MKM3 said; I just read that pulling a full 16A is within spec as long as you only do it for 6 hours. Continuous (longer) pull is limited to 10-13 amps; it is my understanding that the Tesla Mobile Charger recognizes that it shouldn't be pulling 16A and only pulls what's appropriate.

Frank99 | 2017年6月30日

3-phase 230V I understand; how you get 400V out of it I don't understand, but guess I don't need to. Living in the US, I'll never see 3-phase - I know it's ubiquitous in the commercial world, but I only claim to be a weekend residential electrician-wanna-be.

My understanding about the UMC (Universal Mobile Connector) is that it recognizes the type of plug you've attached to the end, and sets the charge current appropriately. I believe that it's also possible to override the charge current and turn it down if you need - perhaps if your Schuko connectors are getting hot, you can turn the charge current down to 10A.

MKM3's example above is what one would expect anywhere in the world from a worn-out (or out-of-spec) outlet that doesn't wipe and firmly grip the prongs of a plug. The same thing could happen in the US. It doesn't really relate to whether a good Schuko plug can handle 16A continuous or not. But, he's a lot more experienced in European electrics than I.

Rocky_H | 2017年6月30日

@mike, About what size circuit to run, that's really variable as to how many miles you do and how fast of a recharging speed will work for you.

@FLHX13 is mostly right about doing a load calculation, but I think he's overstating it where he says that you need 40 or more amps or else you "need" to get an entire main service upgrade for your house. I don't agree. 30A would serve most people fine, and 20A may work if you don't do a lot of miles every day.

Frank99 | 2017年6月30日

I agree with Rocky - 20A@240V = 5 KW charging, which would fully charge a 60 KWH Model 3 in about 12 hours, which would likely suffice for a lot of people. If you drive 200 miles in the morning, and want to come home for a lunch and charge, then do 200 miles in the afternoon, you'd need a bit more power but that doesn't describe most people's usage model.

MKM3 | 2017年6月30日

The line delivers 3 phased 400V at up to 32A (40kW). Teslas only use 230V and 16A so they're well within the specifications.

Schuko plugs are only specified for up to 10A and a short time load of up to 16A. If you plan to draw continuously, you have to get a 3 phased IEC 60309, 3P+N+E, 6h installed (it's even in the installation guide for the UMC here). I guess it's the equivalent of your NEMA 14-50.
Here the UMC is sold with two adaptors, a Schuko and a Red Plug (CEE 16A "camping plug"). Tesla themself advise you to get your electrical sockets and wiring checked before you start using the UMC the the Schuko or Red Plug.

Now you're said it yourself, "it's what you'd expect anywhere in the world with worn out plugs and wiring". That's why I mentioned that you should check everything before using the UMC over longer periods on a standard outlet.
Having plugs that fit anywhere will lead to faults when people start charging anywhere and everywhere over a long time on sockets and wired that may be corroded but are still working flawlessly at lower charges.

All I really wanted to tell you guys is: get everything checked by a certified electrican and maybe invest in higher quality gear before mindlessly charging your new, expensive EV for a day or two on any given plug.