Supercharger at home

Supercharger at home

Hi all,

I keep wondering, why does nobody release (or Tesla themselves for that matter) a charger for home use that is built in and uses the Supercharger tech??

I mean, if I have to install a charger for the high power system anyway, why not let me buy a SuperCharger?! Can't be that expensive?

negarholger | 08/09/2013

Does your house have a 120+ kW feed from the utilities? Typical houses have 240V 100A service... that is only good for 20 kW if dedicated to car charging.

ian | 08/09/2013

Yup. Call up your utility and ask for that size feed. See what they say. Then call an electician for an installation quote. See what they say. Then you'll have your answer.

JPPTM | 08/09/2013

Is a HPWC not fast enough for your everyday needs @ 60 miles of range per hour of charge?

bonaire | 08/09/2013

Seems like a bad idea due to the utility factor of the neighborhood transformer. And, if you dont drive 200+ miles a day and have only one hour to turn around do it again (a taxi service owner, perhaps) then HPWC seems appropriate for most people. 30-40A charging is probably fine for most people.

Timo | 08/09/2013

As a technology a lite-version for SC should be rather cheap. It's basically just stack of on-board chargers. 120kW is 12 of those. Maybe Tesla could offer a lite-version for just taxi services or similar that needs fast charging, but not quite SC -level. Normal household would not need that.

Brian H | 08/09/2013

Elon recently said the hardware for one unit was $15K or less.

Haeze | 09/09/2013

If a taxi service wanted to buy a fleet of Tesla Model S cars for their business' use, I can 100% guarantee Tesla Motors would work with them to install a Supercharger at their location, at the expense of the taxi service. They would probably even do it for cost, since it would be a great source of PR for them.

For the regular home user, I rather doubt anyone would be willing to fork over the $50k or so it would take to have a transformer installed in their house (if their local zoning even allowed it) just so they could charge slightly quicker than a HPWC.

bent | 09/09/2013

A pair of SC spots (1A/1B sharing a 120kW) could make a lot of sense in the garage in larger blocks of flats etc. though. A single house owner would have trouble justifying (to himself and to the electric company) why he should have a 120kW feed but if 10+ band together to get one then that is different.

They would all charge off their regular 10kW outlets (or whatever) normally, and then only use an SC spot when in a hurry. Ought to cover all eventualities.

Brian H | 09/09/2013

Yes, the question of need is central: Who needs fast turnaround? Taxis, and l.d. travellers. Not home users.

bent | 09/09/2013

In the domestic setting there is the occasional need for very fast charging, e.g. when someone returns with the car from a long trip and someone else in the household needs it immediately also for a long trip. Another example is when you get someone dropping by from far off who needs to leave again within the hour for a long distance.

The fundamental reason this can happen is that Tesla's super chargers are ~200km from the big cities and so depending on where you're going you may find yourself in the city with very little battery capacity remaining.

Having access to a private super charger could also be very convenient in allowing you to bypass the last super charger stop on your way to the city, entering the city with low charge and yet still be able to quickly top up there to get back to the super charger ~200km away on your return trip. This gives you +20 minutes in the city to do whatever it is you're doing there before you leave again.

teddyg | 09/09/2013

I think people who are not happy with 95% coverage over all eventualities should just forget about buying an electric car.
You are too demanding and too picky.
Unless you are a billionaire and money is no object sure put a supercharger in your garage. But you will find out very quickly that it was a stupendous waste of money when a 240v outlet is more than enough for most.
Wait a few years anyway...more solutions will present themselves. The EV ship is only just leaving the dock.

Timo | 09/09/2013

How about people that don't have garage? Common problem for city dwellers. Over 50% of earth population lives in cities and those need to charge too. Couple of private SC-lite in a block of flats could be helpful for solving that problem.

I find this a major problem for real breakthrough for BEV:s: there are a lot more households (and cars) in cities than there are garages. Current situation isn't even close to 95% coverage over all eventualities. For example in my block of flats there are five garages and over 100 households. There are a lot more parking spaces than there are garages, so sacrificing one or two for private apartment SC-lite would solve charging problem nearly completely. You would need to charge there only every now and then, or just for few minutes to top off your current charge. If it costs only $15k of hardware that's peanuts for apartment building maintenance budged.

bent | 10/09/2013

If Tesla's competition continues being conspicuously absent from the EV scene I can see "garage has Tesla super charger" as a real selling point for high-end apartment complexes.

Haeze | 10/09/2013

Unless everyone in that block of flats has a Tesla, a Supercharger would be useless. Other EVs will not be able to charge using a Supercharger station.

Timo | 10/09/2013

That's their loss. Tesla is only one making progress in that area, if others don't jump in in that bandwagon soon, only Tesla SC matters, and others are forced to design their cars to use Tesla SC.

Brian H | 10/09/2013

Design? You mean "license". Elon has openly offered that.

Timo | 10/09/2013

Using licensed tech requires design choices.

wilson_th | 11/09/2013

Can't the super charges be installed in Petrol pumps?. They are already connected to the grid always and would also offer coverage. Petrol pump can charge the user some amount for using their super charger.

Brian H | 11/09/2013

480V power supplies and Petrol pumps need a certain separation!

The gas stations are generally unattractive, but IAC not somewhere MS owners like to go by choice. OTOH, air pumps and windshield squeegies ...

S4WRXTTCS | 11/09/2013

There is a rumor that there is a secret San Diego Supercharger going in to someone's home

Now it's just a rumor, and I highly doubt it's true (there haven't been any electrical permits to back up the rumor). But, it would be really, really funny if it was true.

lotusElan | 24/09/2013

I'm actually really interested in a home supercharger, but running from a generator. Specifically, a n appropriately sized natural gas generator. Fire it up, charge for 40 minutes, it shuts down on a timer. The genset also can double to provide backup power to the home via a simple backup switch. And the best feature of all is that natural gas is far cheaper per kWh than grid electricity.

Brian H | 24/09/2013

Interesting idea. Can it deliver 200 kW?

negarholger | 25/09/2013

You can buy commerical NG generators 150 kW for $30k... just make sure you schedule the crane for delivery... it weighs over a ton.

jensjacob | 04/11/2013

How frequent would you need to supercharge at home ? If once or twice a day will suffice then here is an idea :
Get a battery similar to that in the Tesla. Or lets just say 100kWh to get round numbers.

An 85 kWh replacement battery for the Tesla should be about $12000 (source somewhere in here :

Just to give you an idea of the costs.

Since that battery will just be sitting in your basement or in you shed, it can charge continously with 10kW or what ever you have at your house. A full charge will then take about 10 hours and when you get home from work and need to supercharge you can move 60-80 kWh within half an hour or so. - Only limited by electronics and charge and discharge rates of the (Tesla) batterytechnology. Then it will ofcourse be another 8-10 hours before you can do another full supercharge. I might consider that myself.

Just a thought.
Regards Jacob

jensjacob | 04/11/2013

Needless to say that the same battery could be used for electric back up of the entire household. And for storing what ever you might have of private windmill or solarcell input. But if the primary use is for supercharging en EV - you need to have at least some charge at all times.

ian | 04/11/2013

@jensjacob - This is already available...


jensjacob | 05/11/2013

Great. So it is indeed possible to have supercharging capabilities at home. At a reasonable cost. All you need is a battery, a converter and a cable, all appropriately sized of course.

Earl and Nagin ... | 05/11/2013

Cheaper idea;
Buy another Model to be charging with an HPWC while you are driving. It will be ready to go when you get home.
Besides you already have Supercharger technology at your house. The basic charging unit for a Supercharger is simply the onboard charger. You even have the option to buy 2 of them if you want to use the HPWC to charge faster. A supercharger just has 12 of them while you only have one or two.

JaredBanyard | 05/11/2013

Yeah pretty sure you need at least 3-phase 480v / 400A service to your house (nobody has more than 2-phase 240v unless you live on a compound or at a commercial property). I'm assuming the Superchargers are 3-phase, and at 480v service, would require 250A to hit 120kW.

Timo | 05/11/2013

Depends where you live. In here three-phase 400V is quite common, pretty much every detached house has it. Not 400A though.

jensjacob | 05/11/2013

I will try to be a little clearer then...

I don't want 'at least 3-phase 480v / 400A service' in my house and I don't need it.
I want to supercharge the in-car-battery using an in-house-battery with similar capacity and characteristics. If such a battery can deliver 300kW peak to a Tesla-S engine I suppose it can charge another battery with a measly 120kW. And yes, I am aware that I can only re-charge that stationary battery with 10 kW and that it will take 10 hrs to do so. But I don't care because I will only need to do such a supercharge twice a day at most - 10 hours apart.

Would such a solution consisting of : one 85kWh battery, 12 chargingunits and 1 meter of thick cable, be more expansive than a Tesla-S ??!

Timo | 05/11/2013

You can't use those chargers like that. You would need DC-DC converter and those are AC-DC converters. It probably would not cost as much as Model S if you consider only parts needed, but that kind of solution does not exist, so designing and actually building one could well cost you more than Model S. It would not be an easy task.

jensjacob | 05/11/2013

Of course, stupid me. I missed the DC-DC vs AC-DC converter issue which should have been quite obvious to me. I was not aware that a DC-DC solution for this specific purpose might not exist. But I can imagine that it is not cheap.

Earl and Nagin ... | 05/11/2013

In addition to the DC-AC converter, a Supercharger will need a significant Air Conditioner to keep your home battery cool as well as the battery management computer to control the charging protocols.
If mass produced, these could probably become a lot cheaper than a Model S, however, given the limited market, I doubt that enough would be sold to support mass production of such a product. Tesla and its investors have already put the Model S into mass production.
As one of the first Tesla drivers (Roadster in Nov, 2008), I have only really needed the HPWC level of charging a few times, when I had done a lot of driving during the day, then needed to charge quickly in order to go out in the evening. I can't think of any times when I truly needed to go from empty to a full charge in only a few minutes as the Supercharger enables. The HPWC charges at around 60 miles per hour, enabling you to make a 30 mile round trip in the hour it takes to shower, and dress for an evening's festivities. For me, that has always been sufficient but it does call for the dual onboard chargers and HPWC.

Brian H | 05/11/2013

E and N;
Is not the Roadster hi-power AC charger called a HPC, and the Model S unit a HPWC? Seems like a useful/necessary distinction to keep in mind.

inlinenate | 05/11/2013

I think many of you are confused regarding wattage, voltage, current, AC to DC and vice versa. A 500A 3 phase service to a property (although not a real possibility, as services would either be 400A or 600A) is enough to power a small manufacturing plant with multiple motors, large transformers, in addition to lighting and office space. Usually the building size would 15-30,000 sqft. or greater.

I find it unlikely that the 120kW SC is referring to one single charger, as the wire to the car would be between the sizes of 4/0 to 250 MCM copper, much heavier than any soccer mom or business professional is willing to haul to their vehicle and plug in. The 30A/240V home units that most other EV are using only draw 7.2kW maximum (likely around 5.76kW max in reality) from the grid. I am sure that the 120kW number is actually the total draw for all 6 SC units at a charging station not just one. That would mean that each SC would actually only draw 20kW each, which if using 3 phase-480V (600V in Canada), each would draw 25A on the 480VAC side of the charger(19A on the 600VAC side in Canada). Large chargers used for forklifts and the like, have between 15A-30A feeds supplying them if at 480VAC, and 50A at maximum if supplied by 208VAC

Also, to clarify, no residential single detached home would ever be allowed to have a 3 phase supply brought to it, unless it is well over 10000 sqft in size, and would probably have to be using electric heat exclusively to justify the service upgrade. If you are wondering about my math, when dealing with 3 phase systems, voltage x current does not equal watts as it would in single phase equations, you must first multiply the voltage by the root of 3(1.73 approx.) then mutiply that number by the current. ie. 120,000W/(480Vx 1.73)=144.6A, not 120,000W/480V=250A

To put all this in prospective, I would be very surprised if the entire Tesla headquarters(including the assembly plant), which is likely running 480VAC 3 phase, is supplied by more than an 800-1200A service. And they probably have a full SC station fed from that same source.

Brian H | 06/11/2013

Brace yourself. An 85kWh battery that half fills in 30 min requires what?

Timo | 06/11/2013

SC is DC charger. So 120kW/480V is correct calculation (assuming charging voltage is 480V). How big grid connection whole SC has depends on how many charging units it has. Power lines are probably in kV area connections, not something you have in houses or small manufacturing plants.

inlinenate | 06/11/2013

I am referring to the AC supply to the charging unit, which can vary greatly, from 600V 3 phase to 240V single phase. I'm just trying to convey that a SC is possible in a residential environment without needing a 600A service to run the thing, and that a 600A-480V 3 phase service is a ridiculously massive thing to run one battery charger for any size of car.

Earl and Nagin ... | 06/11/2013

@Brian H,
Yes, you are right, the home charging station for the Roadster was referred to as the HPC (High Powered Charger), the Model S one is referred to as the HPWC (High Powered Wall Charger).
The max charging current for the Roadster's HPC is actually 70 Amps while the the Model S maxes out at 80 Amps for slightly faster charging. Conceptually, they are about the same and given the Roadster's better efficiency, the charging speed for the Roadster is a bit faster.
At our house, we have a Clipper-Creek CS-90 J-1772 charging station that can charge Leafs, Volts, Roadsters, and Model S (adapters needed for Teslas) at 70 amps.
As I've mentioned, either is more than sufficient for most of our home use over the past 5 years.

JaredBanyard | 06/11/2013

Well if the stated charge time on a 240VAC/40A charger for a 85kWh battery is ~9 hours and a the stated charge time for a Supercharger on the same battery is 1.25 hours, the huge improvement in charge has to come from somewhere. The Supercharger chart claims to be 12 times more powerful than 240VAC/40A. (10kW to 120kW). So I would guess thats where the 480VAC/240A came from. If they are charging 7000 laptop battery cells at once, I could understand this sort of load. A random laptop around my house takes in 120VAC and outputs 20VDC/5A. Multiply that by a lot, and there you have it.

Of course I'm just spitballing here :)

jeff | 07/11/2013

What I would think is more realistic (and something I would like to do) is enable a business (or even a group of Tesla owners) to install their own supercharger.

I recall an official source saying that the superchargers cost about 100K each (I may be recalling incorrectly, but that seems realistic). If there are 10 Tesla owners willing to fund, and one of them has access to a commercial property that could be used with sufficient power (for example, an RV park), why not permit them to build their own SC? I would gladly put up 10K to fund a supercharger along I-57 between Chicago and Memphis; maybe I could find 9 others willing to do the same (maybe not). And, a "lite" supercharger at maybe 80kW might be a lot cheaper than 100K.

It is even possible that a business might be willing to build their own and charge for it if they thought it would bring business in for their main business (an RV park located on a main route? shopping center? maybe even chargepoint).

If Tesla permitted (or better, encouraged!!) this, there would be access issues. I doubt that the privately funded chargers would be free and a privately funded charger might be limited to only members of the club that funded such. That doesn't seem to me to be a deal killer issue though; a private supercharger that requires membership or is pay-to-use is better than none.

Given the relatively slow pace of supercharger construction (outside of the East and West coasts), this seems like a better way to incent SC construction especially in more remote areas that are on trafficked routes between cities (and not on the I-80 corridor that Tesla has committed to build out).

I would prefer that Tesla do all the work, but it is clear they cannot, at least not across the entire US, and especially in the midwest and south. Why not permit private industry and wealthy Tesla owners to help out especially where there is a strong need and willing contributors?

Brian H | 07/11/2013

Don't get your hopes up. TM is not selling chargers and the control systems, AFAIK. A distraction.

Earl and Nagin ... | 07/11/2013


I assume you have filled in the form that Tesla provides at
"How can I help bring a Supercharger to my area?
Contact Tesla with your suggestions here."

It leads you to the following link:

I don't know what Tesla does with these forms but if you have a place in mind and are willing to provide significant material support, I could see how Tesla might be interested.

Jshulman | 25/03/2014

That can't be good for battery health.

agodshall | 14/07/2018

> Yes, the question of need is central: Who needs fast turnaround? Taxis, and l.d. travellers. Not home users.

Well, here's a use case. I have an apartment. No garage. I could plug in, in front of the apartment, attended, and my neigbors would be fine with it as long as I'm around to move my car when needed. And I'm having powerwalls installed, which charge from my solar panels over time. I'd love to get more solar panels, but without a powerwall-based supercharger it makes little financial sense (the utility doesn't pay anything worthwhile for excess generation, it's just netted against my bill) | 14/07/2018

@agodshall - For 120 kW supercharger, you'd need at least 24 powerwalls (5 kW each), and that would only support 1 car for about an hour - then they'd be exhausted. You'd also need a massive solar array to charge the powerwalls. Significant custom electronics would also be necessary to convert the 2 phase 240V power from powerwalls and the solar inverter to 480V 3 phase required by the Supercharger. I can't see any apartment owner willing to pay for all this - likely in the $150-250K range.

Apartments are a tricky situation, as often the parking places are not next to units, and running metered power from each apartment to the parking stall will be expensive. Few apartments have the power needed to also power even a 7kW connection (30 amps), so a new panel and major rewiring is necessary or separate metering is needed.

Yodrak. | 14/07/2018

"Significant custom electronics would also be necessary to convert the 2 phase 240V power from powerwalls and the solar inverter ..."

Residential solar panels and power walls are 2-phase? Standard residential service is single-phase 240 volt. I would expect residential solar panels and power walls to be compatible.

reed_lewis | 23/07/2018

What I find interesting is that this is a 5 year old post that has resurfaced. The amazing thing is that in 5 years, the Supercharger network has grown by leaps and bounds.

But as to the power required to Supercharge a car, TeslaTap is correct. Where I live I have 240V, 200Amp service. That is a TOTAL of 50 kW of power to my house. A Supercharger can charge up to 120 kW, that is over 2 times the amount of power that my house can consume.

Earl and Nagin ... | 23/07/2018

If you read that recent post, you'll see it is simply someone trying to sell something. It is totally unrelated to Tesla or Superchargers at home. Probably from a spambot.
Just flag it and move on.