Embarrassing question: benefits of a wall charger?

Embarrassing question: benefits of a wall charger?

I'm about to run a new line to my garage and wire a 50a plug so I can charge at home.

I keep seeing reference to the tesla wall charger. From what I can tell this does the same thing.

There has to be something I'm missing?

JayInJapan | 26 juni 2016

It's a dedicated system for your charging at home. Just plug in. The UMC can stay in your car for when you're out. I have a 100 A circuit just for my car. I don't own a UMC; I use CHAdeMO mostly when I'm on the road. Think about your own circumstances and habits. Your situation may require a different set up from others.

mathwhiz | 26 juni 2016

A basic description of the two options can be found here:

I have an HPWC (now known as the Tesla Wall Connector) because my Model S has dual-chargers (essentially now known as the high amperage charging upgrade). As a result, I can home charge at a faster rate than by using the supplied Universal Mobile Connector (UMC). Also, some owners like to install a wall connector so the UMC and adapters remain in-vehicle. There have been a bunch of times on trips that I've encountered other owners that confessed to having forgotten their UMC (hanging on the wall at home). Last, the wall connector is permanently wired rather than plugged in.

whitex | 26 juni 2016

If your wiring supports only 50A the HPWC will perform about the same (there are some slightly lower losses because the charge cable is thicker and therefore lower resistance, plus no losses at the socket). The other benefit would be not having to unplug your UMC if you want to take it with you (those NEMA 14-15 are not always designed for daily plug-unplug cycles, they get loose and can cause issues). That said, if you have refreshed 48A charger you will get 10% faster charging if you wire your HPWC to something higher than 50A. If you are wiring an HPWC I'd suggest a 100A wiring (cost difference is not much up frony) so you have room to upgrade in the future too.

Run4Waffles | 26 juni 2016

Great points above. This was agonizing for me. I only have a 50amp breaker. All you need, on a regular basis, is to use your UMC. You only need to unplug it and take it with you on trips.

Your car is charging at night while you sleep. It doesn't matter if it takes, let's just say, 5 1/2 hours to charge vs 3 or 4 hours.

There's no need to spend the extra money for the wall connector. Unless you really want to.

Hope this helps.

tes-s | 26 juni 2016

Get a wall connector so this does not happen.

That is not the first report of something like this happening.

Anthony J. Parisio | 26 juni 2016

I would like to add that I leave my car parked outside all the time. There's less chance of water and anything else getting in between the connections of the HPWC. All way around it should be safer, easier, faster to plug it in plug and better in the rain.

mm7nyy | 26 juni 2016

@codymail, its not a stupid question I asked my electrician and he told I don't need it, alot of $$$$ because its a faster charger

teslagiddy | 26 juni 2016

If you're going through the trouble of putting in a new line into the garage, you might as well make it 100 amp 240 volt. You can still put a secondary 50 amp breaker and attach a 14-50 plug as you planned, but you'll appreciate the flexibility the 100 amps with a HPWC gets you. For example you could charge at 58 miles per hour (if you have dual chargers in the car) or if you ever get two Teslas the HPWCs can be daisy chained to most efficiently charge your cars without you having to set charge rate or schedule charging. For now you can just use a 14-50 plug. But I still think running the 100 amp wire is wise and probably won't cost that much more than a 50 amp wire.

dortor | 26 juni 2016

+1 Teslagiddy - if you are only running 50 AMPS you can at least pull 100 AMP rated wire - that way in the future if you find a way to upgrade it's a simple breaker swap at either/both ends and you're good.

Redmiata98 | 26 juni 2016

The big difference in cost is if your current setup will NOT support the 100 amp line safely. Then you would have to get an increase in service. The utility company will usually not charge for the service upgrade but your electrician will have to do some work that would cost a bit more. Make a decision on what you want and then go for it. It is far cheaper to decide on the 100 amp line now than to do a 50 now and increase it later.

I went with the service upgrade and the 100 amp line and the HPWC. I also got a separate meter for the charger which allowed me to get the cheaper time of use rate on the charger and keep the house on the current plan. My TOU plan drops the price to 0.08/kw vice 0.12/0.16.

Opafiets | 26 juni 2016

For me there are several reasons to have a wall charger:

1 - UMC is always in my car and ready for any eventuality. I've only needed it once outside of longer trips but was very glad I had it. OTOH, I may well have thought about it and stuck it in my car just in case that day. Not likely though, I'd have forgotten until 20 minutes after leaving home in the morning.

2 - HPWC is heavier cable and more robust. Much better designed for daily use and abuse.

3 - On two or three occasions I've come home and needed a fast charge before going back out. Very glad for 80a charge.

Also, keep in mind that you can only charge at about 80% of your breaker rating so a 50a will provide you with 40a charge (17 mph?). All that said, a 50a outlet and UMC will likely be 100% OK for your needs. At our house in Florida I use the UMC and a 115v/15a outlet (4 mph charge rate) for 3 months during the winter and have only had to use a neighbors HPWC once (though he'd just gotten his X so dual purpose visit :-)

Tesla-David | 26 juni 2016

I have HPWC and enjoy being able to charge at 80A. It does require you to purchase and have Tesla install an additional onboard charger, which costs ~$2,000 to add. Without it you can only charge at 40A with the single onboard charger, standard in MS delivered.

AoneOne | 26 juni 2016

Typo, I'm sure, but 240V 40A gets about 28 miles of range per hour, not 17. | 26 juni 2016

FYI, 14-50 plugs are only good for 32A continuous, not 40A as is commonly stated:

SomeJoe7777 | 26 juni 2016

For the most recent version of the HPWC, another advantage is that it now contains the logic to be able to charge multiple Tesla vehicles on the same circuit. Up to 4 chargers for 4 cars can be connected together and share a single breaker and circuit. The HPWCs will coordinate to charge all of the cars without overloading the circuit.

Bighorn | 26 juni 2016

I think that (32A limit on a 14-50) may be specific to Canada. Where are you?

murphyS90D | 26 juni 2016
40 amps continuous is correct in the USA. The Tesla web site is wrong. Continuous current is to be limited to 80% of the breaker rating.

Canada has recently reduced their value.

AoneOne | 26 juni 2016

32A in Canada, 40 in the U.S. Different electrical codes. | 26 juni 2016

Haha, you are all right. I hadn't noticed that my link is local to Canada.

teslagiddy | 26 juni 2016

Good point - we had to upgrade electrical service from the curb to our 60 year old house to accommodate my Tesla(s). Not as expensive as I had envisioned but it was a big hassle which took multiple phone calls and several weeks to complete.

Opafiets | 26 juni 2016

@AoneOne, sadly no typo, just a SWAG.

RandallKeith | 26 juni 2016

A lot of talk about the benefits of a wall connector. How about the benefits of a 14-50 outlet. It can be used for other things. I use mine to occasionally heat the garage with an electric heater. I can also plug in a welder. And when people come to visit from out of town they can plug-in their RV.

Beartooth | 26 juni 2016

If you don't have dual chargers the HPWC will not be useable to its full potential. I just purchased an extra charge cable to plug in at home (and leave there) and carry my original charge cables in the car.

NOLEK SUM | 26 juni 2016

Only advantage I see is that it puts more $$$$ in Musk's pocket. Which he sorely needs as all his companies lose money.

In almost three years/36,000 miles to date I have never ever, missed not having a HPWC. I have a 220/50amp Nema 14-50, which cost $230 wired and installed. Charges automatically starting at 11 PM when elec here drops to 4 cents per KwH. At least once a week it starts at 40 miles or less and is always done in the wee hours. Unless you have an unusual need for a four hour charge, don't waste your money.

NOLEK SUM | 26 juni 2016

I also have dual chargers. Figured they'd add to resale.

GeoffC | 26 juni 2016

I put in a 60amp breaker - didnt want to push the panel farther than that - I chose go go with the wall unit for convenience... This was worth the $$$ for the wall unit.

GeoffC | 26 juni 2016

Oh like Gadfly - I also got the 2 chargers. Wasn't sure I could use them initially - figured the between resale and futures - it would be worth it.
The wall unit can handle up to 80AMPs with a 100AMP breaker. I plan (if I need it) to increase the power from the street - but that will take me a year...
And Gadfly - wish our power here in sunny CA was as cheap as yours - our lowest rate as I remember is about 14 cents...

codymail | 26 juni 2016

Why do you need dual chargers to take advantage of what the wall charger + 100 amp line can do, even though the single charger is all I need for much fm faster-than-that charging at a super charger?

murphyS90D | 26 juni 2016

The charger in the car is not used at a supercharger.

With a single charger in the car the max current is 40 amps. An HPWC is capable of 80 amps but the car must have two chargers to take advantage of it.

JayInJapan | 26 juni 2016

Single charger is limited to 40 A: dual gets you 80.

tes-s | 26 juni 2016

Dual charger would have been nice for anyone at Newark when the supercharger was not working. Would have cut charging time almost in half at the 18kW J1772 charger they have there.

HPWC would have been nice for all the people that came to find their UMC 15-50 plug melted.

SUN 2 DRV | 26 juni 2016

tes-s +1 LOL

CEYA GAS | 26 juni 2016

I have a sub panel feeding the HPWC and a 14-50. Each on a separate breaker. HPWC gets 100'amps, 14-50 on a 50 amp circuit. Norm is using the HPWC at 64 amps (less cable heating), but I've gone to 80 for quick charging, and the 14-50!is available for visiting EV's or motor homes...

I like the permanence of the wall charger and leaving the UMC in the trunk with a slew of adapters.

Figure I'm pretty well covered!

codymail | 26 juni 2016

Why doesn't Tesla sell a version of a HPWC that converts your house AC power into DC and throws it directly into the cars battery, bypassing the cars internal charger.

The way the superchargers work.

Wouldn't this allow people to use a wall charger up to 100 A or even more without needing dual chargers in the car?

pepsundar | 26 juni 2016

I thought I can use this thread instead of creating a new one as I do have some questions regarding home charging, so please excuse me.

1. Mine is a p85 classic and it has dual chargers
2. In my 8 months of ownership I never had to use the UMC. The super charger facility is conveniently located near my work place so I can swing by, grab a coffee and charge, so I never had to use any other charging.
3. I live in a rental property and I do have a garage for my MS.

I understand that the Tesla wall charger requires permanent wiring, which I can't do since mine is rental. I spoke to the landlord and he agreed to allow me to to install a separate outlet with NEMA 14-50 receptacle so I can use my UMC to charge my car at home if necessary. He said he has a couple of circuit breakers unused in the electrical system that I can potentially use for this. The electrician will be coming over next week. Based on Tesla's website instructions for home charging, I ordered for a HUBBELL 9450A HBL9450A HBL RECEPTACLE NEMA 14-50 as well.

My questions are:

1. Is my decision to go with installing a 240v NEMA 14-50 receptacle correct given my circumstances?
2. should I ask the electrician to do a 100amp wiring and circuit breaker? The Tesla specs says 6 AWG copper cable must be used.

Basically I need to know what to tell the electrician with regard to circuit breaker capacity, wiring gauge / amperage.

thank you

murphyS90D | 27 juni 2016

With a 14-50 receptacle you use a 50 amp breaker and 6 gauge wire. That is the limit for a UMC.

To use your dual chargers you would need an HPWC hard wired on 2 gauge wire and a 100 amp breaker.

Rocky_H | 27 juni 2016

@codymail, Yes, that is how Superchargers work. That is also what a CHAdeMO station is. That equipment you are hinting at, which converts the AC to DC is why CHAdeMO stations cost TENS OF THOUSANDS of dollars, instead of a few hundred. That’s why they aren’t going to sell that for home installation.

pepsundar | 27 juni 2016

@murphyS90D - thank you.

eye.surgeon | 27 juni 2016

95% of owners have no need for a HPWC. I have dual chargers in the car and use the UMC that came with my car. in 18 Months I have used the dual chargers zero times and have needed more home charging than the UMC can provide zero times. The UMC can charge my car completely overnight. Unless you're a taxi driver and have to charge more than once a day at home, you will not need a HPWC.

codymail | 27 juni 2016

Rocky: Thanks!

SUN 2 DRV | 27 juni 2016

Eye.surgeon: I agree that most people most of the time don't need the high charge rates of an HPWC.

However some people find that the high charge rates can be very convenient some of the time.

And a lot of people find the reliability and security of a hardwires connection to be relaxing and comforting ALL of the time, and in fact can contribute to a good night's rest. Vs lying awake worrying about the overheating connections in the garage space next to the kids rooms. :-)

But you're right...a UMC is sufficient for some people, some of the time.

Tola | 28 juni 2016

Before I got my car I installed an HPWC in the garage on a 100 amp circuit because I was intending to put dual chargers in the car. Then, as I learned more about the car I realized that I probably would rarely need the increased charging rate at home and didn't get them. So the UMC lives in the bag in the trunk. I have used it several times, on trips at a destination to charge with a 110v receptacle. I always liked having the feeling of reassurance that the UMC was in the car, since I thought that traveling without the UMC would be a disaster. Now I realize that with the increased number of Superchargers over the past year, and with a CHAdeMO adapter in the frunk, forgetting the UMC would probably not be the disaster I thought I was happily avoiding.

I am hoping that my older HPWC will be compatible with newer model Teslas, so when I get my new car in 7 years I won't have to install new charging infrastructure. :)

jeff | 28 juni 2016

I went through this dilemma as well when I originally ordered my model s, as the 40 amp on board charger was standard. The old style HPWC was about $1200 (CAD), and with Ontario rebate still would cost about $600. There is no way it was worth it for a similar charge rate so I planned to get a 14-50 installed. I was very lucky the electrician was delayed, as they then announced the new version HPWC with a large price decrease, and the refresh announcement came with the announcement on the 48 amp on board charger. I was able to get the new charger for about half the price of the old one (after rebate), and with the new on board charger I get about 55 km of charge/ hr. I am very happy I went this route, but without the price decrease of the new charger and the corresponding amperage increase in the on board charger I don't think it would have made much sense.

PhillyGal | 28 juni 2016

Not an embarrassing question - lots of new owners have the very same question and it all comes down to personal preference.

At the time we ordered, the HPWC was $1,000. If it was today's price, we would have purchased one. Now that it's today's price and we have 28,000 miles on our car, we really don't find a need for it. The only tempting part is the longer cord, since our outlet and panel are exactly opposite where it should be.

Now had the current Tesla referral program still included a credit, I would have jumped to order one as I just got my first referral (yay!)

It comes down to preference and whether or not you'll ever need to charge your car quicker than what the 14-50 will allow (and if you've upgraded the car to even allow it.)

High Plains Drifter | 28 juni 2016

If you look at it a strictly dollar for value aspect, it would be hard for most of us to justify a wall charger. Take money out of the equation and look at it from a convenience point of view. And for some of us it is well worth it.

The wall charger advantages are faster charge times and the convenience of now having to restow your UMC after each usage. As the world's laziest person, the time savings was not significant enough to warrant the wall charger but I would gladly spend $1000 to avoid the 1 minute regiment of rewinding the cord. You will have to decide your need for speed, how lazy you want to be, or how frivolous you want to be with your money.

PhillyGal | 28 juni 2016

Restowing UMC after every use is not normal.

Ours leaves our garage once a month, if that, when we are outside of range to home. Basically, 100 miles away or more.

Rocky_H | 28 juni 2016

@PhillyGal, +1
Yeah, I've noticed this, that people with wall connectors have this mistaken impression that people who use the UMC unplug it and pack it in the car every single day. That by far generally not the case. I only take it off the wall about two times a year.

Davidb0229 | 28 juni 2016

My take on this is a bit different because of my circumstances. This may not apply to the OP.
I live in a condo and park in an open lot. I am in the process of getting approvals and arranging to install a charger next to my parking space.
Although a NEMA 14-50 outlet is technically all I need (and I do not have dual chargers), I am planning to install the Tesla Wall Connector for three reasons. First, because the Wall Connector has safety features that make it somewhat safer in an open parking lot. In particular, the cable won't be energized unless the car is connected. Second, I live in the snow belt and do not relish the idea of having to disconnect, coil up and stow a cold, stiff, wet UMC and its cable in my trunk each time I leave the parking space. (There is no place to leave the UMC in or near my space other than in the car.) And third, a number of posters have said that the Wall Connector cable and connector are more rugged than the one with the UMC. My electrician was also skeptical about the durability of the outlet and connectors with daily plugging and unplugging the UMC from the outlet.
So for those who park outdoors, the decision might be different.

steveg1701 | 28 juni 2016

I think the wall connector is a near necessity for those of us who don't have a garage

AoneOne | 28 juni 2016

Outdoors, you can still use the UMC, so long as you put the 14-50 receptacle in a NEMA 3R rainproof enclosure (see A locking enclosure large enough for the UMC adapter plug will keep everything secure.