# Forums

## Supercharging at home?

Could someone help me understand why am I (presumably) able to charge the car super-fast at a Supercharger station, but am required to upgrade for a secondary charger in my car, in order to get higher charging rates at home?

tesla | January 12, 2017

To follow up on the above question -- is that because at home I am getting AC current from the outlet and the on-board charger needs to convert it into DC, while at the station the car gets DC current directly and gobbles as much as it can take?

Dramsey | January 12, 2017

Yes, that's pretty much it. Supercharging is a high voltage, high amperage, direct DC connection that _does not_ use the chargers in the car.

You don't have this type of power at home (nor can you get it), so you're limited to AC charging.

Rocky_H | January 12, 2017

That is part of why AC and DC charging are different methods. The other is just a straight-up difference of power levels. A house with a 200A main electrical panel can do a maximum of 240V times 200A = 48kW. That would be using the entire electric feed of your house just for charging the car and nothing else. Supercharging the car can be 100-120kW, more than double that.

Earl and Nagin ... | January 12, 2017

Its really quite simple:
Tesla makes a basic ~10 kW charger. It takes AC from the grid an converts it to DC at the right voltage and current that your battery can handle, adjusting the voltage and current based on the power available from the grid, your state of charge, battery temperature, and other factors. One can connect these chargers together to provide more power depending on how many you want to buy and how much power you want to pay the power company to provide you with.
Each Tesla comes with one charger in it to allow you to charge at up to ~10 kW DC. It can draw between 120 and 240 volts from the grid at from 12 to 40 amps depending on what your wiring and grid connection can provide. You can optionally buy another charger to put in your car allowing it to charge up to ~20 kW DC if your house can provide up to 80 amps and 240 volts.
A Tesla Supercharger is 12 of these 10 kW chargers, all tied together to provide up to 120 kW of DC. It, of course requires a ~480 volt, ~250 amp connection from the grid, something no normal house would have available and you'd have to buy 11 more chargers. Tesla generously provides those stacks of 12 chargers in public places, calling them Superchargers, where their customers can share them to get fast charging without having to buy anything else for their cars.
Its really a great thing!
Go Tesla!

Frank99 | January 12, 2017

The important thing is your house, if it's relatively new, has 240V, 200 Amp service. To get Supercharger level charging, you'd have to have 240V, 600 Amp service just for the charger - the wires coming into your house would be the size of your arm, not the size of your thumb.

Industrial sites can get this kind of service (actually at higher voltage to keep the amps (and required wire size) down). Residences are unlikely to be able to request this level of service without a really big payment to the local electric utility (or, you can burn down three of your neighbor's houses and use their service).

reed_lewis | January 13, 2017

@Earl and Nagin. Just to correct your numbers.. The new model Teslas have a 48 Amp charger which at 240V means you can have up to 11.5 kW going to the car. The portable cable that comes with the car only allows 40Amp which means that only supports 9.6 kW The upgrade for the car allows 72 Amp charging which means 17.28 kW power.

So the car can accept up to 48A at up to 240V AC in a standard configuration. And if you have the upgrade of the chargers in the car it can accept up to 72A at up to 240V. But in order to get 72A at 240V, you need to have a Wall connector connected to a 90A circuit.

bp | January 13, 2017

From a technical perspective, it should be possible to install a supercharger at home - but the cost would likely end up being considerably more than the price of even a P100D - and probably doesn't make sense since home charging usually doesn't need to be completed in an hour.

Rocky_H | January 13, 2017

@bp, I still don't even think you could though. The electric utilities generally don't run the 480V three phase connections into residential subdivisions, and I don't think they would be willing to do it, no matter how much you paid.

TeslaTap.com | January 13, 2017

Back in 2012 I asked PG&E (California) what it would cost to get 480V 3 phase to my home, and they said no way. I got the impression it might not be allowed in a residential area. Later I found that Tesla charges more than \$100K for Supercharger hardware making this really impractical. That said, there have been some private Superchargers. It appears Jordan has three sites, not on the Tesla map, so I expect they are not paid for by Tesla.

Earl and Nagin ... | January 13, 2017

@reed_lewis,
Thanks for replacing my ~ with the latest precise numbers. When you've been a Tesla customer for more than a decade, keeping track of when the least significant digits that change with design tweaks gets tedious.
WARNING: gory details to follow. Only true geeks with nothing better to do should proceed :-)
IIRC: Original Roadsters could draw 70 amps from their HPWC, the first Mobile Connectors only supported 30 amps from a NEMA 14-50 outlet. The first Tesla Foundry after-market Mobile Connectors supported 40 amps from a NEMA 14-50 with an adapter kit for many other plugs, adjusting max current for the plug's rating. The next generation of Tesla Mobile Connectors were similar to the Tesla Foundry ones.
Since the Roadster came out before the J-1772 standard supported higher power than 30 or 40 amps, Tesla had to develop their own signalling protocol and chose 70 amps max. When the J-1772 committee finalized higher current charging (because Tesla had shamed them into doing so), they, naturally went contrary to what Tesla had actually implemented and went to 80 amps, skipping Tesla's 70 amps. Early high power J-1772 EVSE owners (like me) then had to get special firmware from Clipper Creek to enable the Tesla protocol for 70 amps.
The first generation Model S supported 40 amps with one charger and 80 amps with dual chargers. The first Superchargers used 8 of these. I'm not sure if there were other generations between the ones I've described and the one you described in detail.

reed_lewis | January 13, 2017

@Earl and Nagin. You are very correct on the old Tesla Model S chargers. They were 40 and 80 amp chargers. It is strange because the new ones are multiples of 24 (24, 48,72) which means that the new chargers either support 72 amps, or it has to be installed.

One thing I have wondered is if you could send 72 Amps through a J-1772 to a Tesla with the appropriate internal charger. That would be interesting.

Goose | January 13, 2017

@reed ... not a big deal, as there are many 80 amp public J1772 charging stations around (especially in Canada) and you use your existing UMC with the J1772 adapter and the dual (or "high amperage") option in the Tesla to get full use of the available juice.

Rocky_H | January 13, 2017

@reed_lewis, Quote: "One thing I have wondered is if you could send 72 Amps through a J-1772 to a Tesla with the appropriate internal charger. That would be interesting."

Yeah, that is easily done. They are a little more rare, but there are a fair number of J1772 stations out there that can provide 80 or 90 amps. If you use the adapter with a Model S, it will pull as much as it is capable of, which would be 72A.

@Goose, Quote: " and you use your existing UMC with the J1772 adapter and the dual (or "high amperage") option in the Tesla to get full use of the available juice."

I think you just have a simple mistake in here. The UMC would not be involved. That is the mobile connector for plugging into wall outlets and doesn't have anything to do with the J1772 adapter.

tesla | January 13, 2017

Thank you for all the details!

Goose | January 14, 2017

@Rocky, correct - UMC is not part of that scenario. I have done that kind of charging dozens of times ... brain burp. Thanks.

epilog | February 17, 2017

A lot of misinformation in this thread.
Regarding what is available in a regular home:
1. Most houses in Europe has 400V 125A 3-phase. This can deliver up to 86KW, but since the house need some, plan no more than 69kW, and it will cost extra for industrial grade parts. If you want to keep it cheap (with all residential parts, 63A or 43kW is the limit.

2. In US it is usually 230V 200A single phase. Often the transformer on the pole will not deliver enough if it is shared by many houses. This will possibly give 46kW, but more likely less than 25kW, 15kW more likely, limited by power company's distribution transformer, but you can talk them into upgrading this.

It is cheap and easy to convert this to DC if needed. A 125A 1600V 3-phase rectifier costs \$20.

Bottom line for only residential components you can get s supercharger up to 43kW in Europe. US up to 25kW.

Jeff Hudson | February 17, 2017

All of these answers are helpful. @Tesla, I would add an observation to the answers that might be helpful although it may seem so minor that it's not worth mentioning.

Many people that are new to EV's and charging them can be and are frequently confused by the actual charging connector itself. The variety of other EV charging connectors are more complicated than the simple looking Tesla hardware. The Tesla charging connector does double duty with its elegantly simple connector. Other answers have assumed a new curious enthusiast understands this but I do not think it is so obvious to those newcomers. Both AC and DC current can be input through the same Tesla connector. AC is the electrical output at the house and other destination locations while DC is the electrical output at a Tesla Supercharger. As already mentioned the Supercharger DC electrical output is high voltage and high amperage which bypasses the vehicle onboard charger (rectifier). There is a direct path of communication between the Supercharger and the vehicle battery managing the process.

janendan | February 18, 2017

I've read that charging lithium ion batteries this fast can damage the electrodes, consume the electrolyte wth multiple side reactions and shorten the life. What is the optimum charging power, voltage, current?

Rupindersinghsuri | June 23, 2018

Can any one guide I am importing Tesla x 100 d. From UK as I needed right hand drive. I have three phase 240 v. At home as well as in my office. What charger normally comes. As I have asked for super charger. And he is giving me at additional 4500 pounds.
But now after looking at your blogs. I don't think it's super charger.

How I can charge it at faster pace. What shall I purchase extra

TeslaTap.com | June 23, 2018

@Rupindersinghsuri - I have no idea what additional item you're getting charged 4500 pounds (about \$6000 US). A HPWC in the USA are around \$500 and is the fastest system for residential charging. The US HPWC is 2 phase, but the European version is 3 phase.

One report is a Supercharger is about \$100,000, so you're not getting one of those (and they require 3 phase 480V at 192 amps, at least in the USA).

Yodrak. | June 23, 2018

"The US HPWC is 2 phase"

It is? Are you sure? US residential service is 'split' phase, 240 volt single-phase tapped in the middle so as to provide both 120 and 240.

Patrick | June 23, 2018

I'm reading all the charging threads this afternoon and will chime in. The US HPWC operates with 240VAC single phase electrical service at up to 80A on the supply side. Two hots and one ground are required, apparently the customary neutral connection is optional.

TeslaTap.com | June 23, 2018

@Yodrak - You're right. Thanks for the correction!