Twin chargers vs. Supercharger

Twin chargers vs. Supercharger

I am planning to get the 60kwh and wondered if it would be best to get twin chargers or the supercharger option. There has been some mention of using KOA/RV sites for charging but it sounds like their hook-ups are high powered, but not to the same level of the superchargers. Would the twin charger be needed at a KOA/RV site or would a standard plug work? Is there a reason to have both twin chargers and the supercharger? Opinions please.

nwdiver93 | 13 January 2013

Twin Chargers will not charge any faster than a single charger with the mobile connector. You need an HPWC or J1772 capable of >40 amps to take advantage of twin chargers.

DouglasR | 13 January 2013

Both twin chargers and supercharger capability are helpful, but for different reasons.

Twin chargers will allow you to charge faster from high amperage (70 amps +) power sources. If you install the HPWC in your garage, you could then charge twice as fast with twin chargers (of course, since most charging in your garage is overnight, you probably don't need it). On the road, there are not too many high amperage power sources. Sun Country Highway has installed a series of them across southern Canada. Roadster owners have installed a number of them, particularly up and down the west coast, but most require a Roadster/Model S adapter, which is not easily available.

Note that the NEMA 14-50 outlets found at KoA and other RV sites are NOT considered high amperage power sources. They charge at 40 amps, and so twin chargers offer no added benefit for them. They will work with one of the standard adapters provided by TM.

If more high amperage power sources are installed in the future, then the twin chargers will offer added flexibility. While it is theoretically possible to add twin chargers after you have received your car, I have tried but so far been unable to do so. I also expect that adding the second charger will be considerably more expensive than configuring twin chargers while the car is being built.

Supercharger capability allows you to charge at TM's network of DC fast chargers. These are MUCH faster than using either single or twin chargers. However, there are only eight or nine superchargers currently in operation, and it will be a year or two before these are installed along major routes in the U.S. Even when the network is fully built out in five years or so, it may not cover everywhere you want to go. When the network is built out, however, it will make travel between major cities reasonably feasible and quite inexpensive, because the charging is free (although long distance travel will still be somewhat more difficult in a 60 kWh car than in an 85 kWh car). If supercharger capability is built into your car, no special adapters are required. If that capability is not built into your car, you will not be able to add it later.

Michael Emrich | 13 January 2013

All J1772 chargers so far provided just 30A. How can I find a J1772 with a higher amperage, please?

Sudre_ | 13 January 2013

IF TM ever makes a CHAdeMO adapter (which is DC) it would also not use the twin chargers and provide a potential 50kWh (half a supercharger).

DouglasR | 13 January 2013

@Michael Emrich,

I believe the Sun Country CS90 provides high amperage. Take a look at this map -- many of these chargers are CS90:

dtesla | 13 January 2013

Max. amps for the J1772 is 80A. I know of no 80A J1772 chargers today. But as EV get more popular with larger on board charging units....

gregv64 | 13 January 2013

Nobody has come out and said it, but in my opinion the supercharger is a much better bet. It's really uncertain whether you will ever see much high amperage chargers, and even if you do they still are pretty impractical for traveling any distance (only a max of 60 ideal miles of charge after an hour, and that's more like 50 real miles, so it's charge for an hour to drive 50 minutes). If you're charging overnight then dual chargers aren't necessary, if you are charging during a stop then dual chargers aren't enough. Superchargers, however, really change what you can do with the car.

Brian H | 13 January 2013

The twin charger is useful at a KOA site only if you rig up a "Multi-Input EVSE" device that accepts two plugs at once. Each plug is 40A, which matches one charger's capacity (14-50 standard). One guy ('Peter') is an EE who did this: .

DouglasR | 13 January 2013


While I agree with you generally, it does depend on where you live, among other things. Here in Seattle, we are on or close to both the Sun Country Highway across Canada and the Tesla Highway (70 amp Roadster chargers) running from Vancouver BC down to San Diego. In addition, quite a few other high amperage stations are available throughout the state, or soon will be. These are or will be important because they cover areas where the SC network is not likely to be found. By stopping for a couple of hours, you can add 100+ miles, which makes for a pretty full driving day.

I am 3146 | 13 January 2013

I have both on my MS. My thought was the supercharger is great on the way to my destination (since that is how the system will be built out). The twin chargers come in handy when you are at your destination or when you don't have time to charge over night. Say you go take a short trip during the day, you come home and have dinner plans. With the HPWC, 100 amp circuit and twin chargers, you can plug in, take a shower, get dressed, get back in the car an hour later and have 62 more miles of range.

gregv64 | 13 January 2013

If you get the HPWC it could be useful, although I'm not sure I ever drive over 200 miles in a day and then actually want to go out again in the evening. Otherwise I wonder how many times during the period you own the car that:

A) The extra range provided by a high amperage charger over a regular charger will be what you need (i.e. you have an hour, your car doesn't have enough remaining range for what you need and 30 extra miles isn't enough but 60 is)


B) There is a high amperage charger available

I almost ordered it, because there is always the feeling that it could be useful, but I'm just not convinced it will actually come in handy for people in real life. My one trip right now where it probably would be nice is driving to Santa Barbara, but I'm sure there will be a supercharger along the way sooner rather than later. When I really thought about it I couldn't justify 1500 dollars for something that might perhaps save me an hour or two over the next several years.

djp | 13 January 2013

Michael How can I find a J1772 with a higher amperage, please?

I bought a Clipper Creek CS100 when I got my Leaf a couple years ago. Pre planning for higher charge needs in the future. Will deliver 80 amps off 100 amp circuit.

Neech | 13 January 2013

Thanks everyone. I was worried I was missing something with the twin chargers because I had decided early on against them, and that regular overnight charging would be enough. When I take a road trip, I like to get where I am going (and need a radar detector if you know what I mean), so I doubt I would have the patience to delay my trip several hours to charge up. It sounds like the twin charger only helps when using the HPWC. I will likely get the Supercharger, but I live in the Chicago area and we don't have them YET, but I hope they turn up soon.

iholtzman | 13 January 2013

I too live in Chicago and have my Model S. I personally think twin chargers are a waste. I did not get it. If you have a 240 volt nema 14-50 you will be fine. In my opinion the twin charger HPWC set up will be considered obsolete before long. Chicago should be the next major market to get superchargers and I think DC charging will become more popular in the future. If Tesla can develop superchargers so will others.

Robert22 | 13 January 2013

There are no plans to place superchargers in major cities. My understanding is they are designed to be "en route bridging devices". In most cities, there are adequate numbers of existing charging options (hotel, Chargepoint, etc.). Superchargers were never designed to supplant home or metro charging stations. It makes sense.

Twin chargers provide the option of getting out of dodge a little more quickly. For some, that might be important capability.

lph | 13 January 2013

I thought that Tesla is going to use CHAdeMO for the Japan Model S. Hope that they will also do the same for the US soon. At 50kW it will charge at about 150 mph. Not a supercharger but still pretty good if traveling long distances and not in a hurry.

Peter7 | 14 January 2013


One question I have for you is what type of trips (and where) do you plan to be taking? I have put almost 6k miles on my S in three weeks so my answers may well be differnt than yours.

I have both the supercharger option and the twin chargers and have used both heavily.

Superchargers are the ultimate, they are easy, quick, and placed at great locations, which makes using them in the S almost exactly the same as driving a normal car. From my experience and the numbers I've taken from my longest single day drives, my long 1000 mile day drive would increase in length less than an hour from where it stands now under worst case conditions and could end up being the same. (Trip times in the 12-16 hour range). I couldn't imaging getting an S with plans to drive long distances (200 miles +) without it.

Twin chargers are a bit harder of a question. I use mine all the time and used them tremendously durring the trip. You really have to ask yourself what your time/travel time is worth. Cutting a full charge from 8 hours to 4 in the middle of the day makes a huge difference in how far you can travel in a day. Being able to stop home for a few hours in the evening while I get ready to go out and add 130 miles of range before heading out has mattered a good deal to me over the last week or so, perhaps that will settle out in time, but the twins have already paid for themselves a few times. I use them at the following:

1. Home where I'm using my evse until the HPC comes in.
2. Tesla stores which have the HPCs available when passing through town.
3. RV parks where I could hook into two 14-50Rs.


DouglasR | 14 January 2013


How do you hook into two 14-50s? Did you build a special cable?

Regarding the twin chargers, not getting them is the one regret I have about how I configured my car.

TeslaTech | 14 January 2013


Ah, you're that intrepid, gonzo engineer who just drove cross country! I thank you and your co-pilots for the write-up on your blog:

All that's left are some pictures, movies and the write-up of the final leg of your trip to finish feeding our addiction of all things Tesla Model S. Come spring, I'm sure the Canadian Sun Country Highway will beckon, right? That's some glorious country up there.


I hope when things slow down for Tesla you'll be able to add that extra charger.

roofmonkey | 14 January 2013

When I configured my Model S over the phone(the My Garage feature has never worked for me) The sales person at the other end actually talked me out of the Twin charging system.

It was only 4 weeks ago when the Sun Country Highway car came through Winnipeg that I started looking into the matter in earnest.

Their network has a large number of CS-90 charging stations along the TransCanada Highway. 60 miles per charge hour vs 30 without twin chargers.

This will make having twin chargers a must for owners wishing to make longer road trips.

Thankfully I still have time to make the change as I opted for no active suspension.

Pano roof
Tech package
Sound package

gregv64 | 14 January 2013

"This will make having twin chargers a must for owners wishing to make longer road trips."

I still maintain waiting an hour to go an extra 60 miles is almost useless for making longer road trips anyway, barely better than 30 miles per hour. Either case only really works if you need to slightly extend your range. People that aren't EV fanatics won't find waiting 4 hours to charge during the day any more palatable than just stopping for the night and charging 8 hours.

DouglasR | 14 January 2013


I strongly disagree. For me, it is the difference between taking two days to drive from Seattle to the SF Bay Area or taking three days. Mostly, it means added flexibility: being able to reach a charger at a Tesla store before closing time; being able to make a particular motel that has a 14-50 outlet so that you can start off full the next day; being able to take a detour to see a sight, and not lose any miles.

In a long day of driving, I often make a couple of extended stops to eat or sight-see. If I could add 100-200 miles during that time, I would consider that a pretty productive day. If an added 60 miles is useless for making longer road trips, why not just get the 60 kWh battery instead of the 85 kWh battery? It's about the same difference.

murraypetera | 14 January 2013

It is not about waiting an hr for 60 more miles but waiting 15 min at a charger to top off instead of 30.

Higher current public chargers will come. AC 80A is a lot cheaper and easier to install than 480vDC.

gregv64 | 14 January 2013

"In a long day of driving, I often make a couple of extended stops to eat or sight-see. If I could add 100-200 miles during that time, I would consider that a pretty productive day. If an added 60 miles is useless for making longer road trips, why not just get the 60 kWh battery instead of the 85 kWh battery? It's about the same difference."

I'll accept that the other is convenient for you, but I will take exception with this. Battery size is about range you can go without stopping or finding a recharging station at all, and that's very important (although by itself it doesn't make really long road trips feasible IMO, only superchargers do that, but it makes reasonable weekend destinations or day trips reachable). It's having to find a recharging station and waiting to be able to go a little extra distance that I don't see doing. For a supercharger it's definitely worth it, for the other I just don't think it is for me (there's no way I'd drive to Seattle until they put in superchargers along the way).

"It is not about waiting an hr for 60 more miles but waiting 15 min at a charger to top off instead of 30."

I suppose if you have a smaller battery pack this makes more sense. With an 85 I don't see the need to ever top off.

bobinfla | 14 January 2013

Here's the scenario that made the twin chargers seem a good idea to me:

Friday, drive to work and back, a 60 mile round trip. Then plan on heading to Orlando Friday evening for a concert or whatever, that's a 100 mile trip each way. The Orlando roundtrip is doable (at my normal highway speeds in my 85kwh) if I put the 60 miles I used going to work back onto the car before I leave. With the HPWC/Twin chargers, I can do that in an hour while I'm changing, packing, etc. Without the twin chargers, it would be a two hour charge cycle, which is now cutting into my time to get on the road.

Daily driving to work and around town doesn't enter into the equation at all, so just think back over the trips you have taken above and beyond those in the past year or two. (I so wish I had thought to start keeping a driving log once I decided on getting the S.) See which ones would be seriously inconvenient if you pick one versus the other.

GoTeslaChicago | 14 January 2013

I read most of posts, even about subjects that I'm not interested in, or I think I know it all already, because so often I learn something new. Thank you DouglasR for the info and link about the Sun Country Highway in Canada.

link repeated here:

I see it might be possible to drive from coast to coast without waiting for the Supercharger network, just take the Sun Country Highway accross Canada!

The CS90 chargers charge at 72 amps with the J1772 connector, so in that case the twin chargers will be useful.

Peter7 | 14 January 2013


"gonzo engineer", that's great, I can't let my co-workers see this or I'll have a new nickname around the office!

The write-ups really are being worked on :), though work had a three week backlog waiting (I had a trip prior to starting the road trip) which has slowed things down longer than I wanted.

The Canadian Sun Country Highway does sound like a lot of fun....


Superliner | 14 January 2013

It seems to me that the Twin Chargers only pay dividends "if" you have the HPWC at home (or access to one on a regular basis) Most public infrastructure can be used at full power by the single 10kw charger. and if travelling long distance 4 to 5 hours is still too long to wait along the road somewhere to get charged up. and if stopping overnight unless you are camped out at a Tesla store with a HPWC "available at other than business hours", again a public charger option at a motel / hotel will likely be able to be used at full power with the 10kw charger any you'll likely be there long enough to get a full charge anyway.

One can envision all sorts of scenarios where an extra X miles may be a make or break deal and therefore justify twin charger capability, but as it stands now the infrastructure in the wild does not support the argument.

Looking ahead .. one could also make arguments that the current infrastructure will improve over time (which it likely will). But one could also argue that so will battery storage capacity and range capabilities perhaps negating the need for >80A + charging equipment in the wild because my future Model ? has a 600 mile cruising range using capacitors that can be charged in seconds as opposed to hours.

Or perhaps Enterprise will be in orbit and send an energy beam to a collector on my car giving it unlimited range. IMHO .. worrying about future capabilities where EV's are concerned would be akin to worrying about what my original iPad would be capable of today when I originally purchased it lol!! It's almost junk today compared to what's available now.

Superliner | 14 January 2013

To add to my previous post think about it,... 20 years ago a 300 mile EV for the masses was a pipe dream, 10 years ago it was done with solar assist vehicles that could carry one person at best at bicycle speeds on flat roads that cost more than the GDP of small nations to build, today there is Model s which can carry 5 + and is a real world solution (all be it still more expensive than Mr. Ave Joe) and 10 years from now ? I fully expect my Model S in 10 years to be like owning an original iPhone or Ist Gen. Android Device. Technology at that time will likely render the current Model S obsolete in terms of capability compared to what is available on the bleeding edge at that time.

TeslaTech | 14 January 2013


"Gonzo" was meant as a compliment, although something of Hunter Thompson must have been evoked by the blog and the description of you field testing and troubleshooting your slick dual 14-50 EVSE at a campground . . . in the rain. You figured it out and it worked well from then on.

Only 2 owners have written of cross-country trips so far, and both excursions began right after receiving the Model S. You are enthusiasts, yes, but also adventurers and pioneers blazing the path for others to follow while showing the capabilities of the car and discovering them for yourselves and us. Most owners will probably wait for the SuperChargers to try such a feat while others know it can be done now and go for it.

The 400 miles on a charge challenge drive, the LA to Vegas MotorTrend jaunt, the D.C. to Florida and back journey; these are trips that set a new level of performance for a mass market electric sedan and the beginnings of a new chapter in automotive history. It's exciting stuff and the first signs of what we hope to see as commonplace in the next few years.

Whose will be the first S to do the cross-Canadian run? There's already a BC 2 BC (Canada to Mexico) rally planned for this year which will have many Telsas (S and Roadster) involved.

Brian H | 15 January 2013

Forget large kWh totals with supercaps, unless you're a truck. You need that much storage space. They're fast, but BIG. Think second row seats, third row seats, and trunk--GONE, leaving the frunk for a little luggage.

Low energy density is worsened by low mass density. VOLUME is the problem, not just mass.

Peter7 | 15 January 2013


No worries, I took it as such :),