Twin Charger vs. Single Charger Configuration

Twin Charger vs. Single Charger Configuration

Trying to decide whether to order the Twin Chargers. Don't really need it for daily use but I gather it cuts the time for super charging in half.

Does anyone know if the Twin Configuration adds weight to the car. If so, how much?

negarholger | 14 giugno 2013

Super chargers do not use the internal chargers... so no difference here.
The only difference is using an AC source... at home or on the road you need > 40 A AC source to take advantage of the twin charger option.

Mark K | 14 giugno 2013

It cuts home charging time in half, which helps if you need a mid day refill (I use that a lot).

No effect at Supercharger.

Adds 10-20 pounds of mass (guesstimate).

Tâm | 14 giugno 2013

Like Kleist said, single or twin chargers has nothing to do with Tesla Supercharger which uses DC, it has to do with AC.

Now, for AC, when you don’t have access to Tesla Supercharger stations:

If you use your car just as if it is a Nissan Leaf that you would never go long distance, then you might not need a twin charger.

If you are at home, you don’t mind sleep 10 hours waiting for the single charger to charge your car.

While you are on the road, you may not have a luxury to sleep that much.

ajamison | 14 giugno 2013

I was told when I asked about this at the Chicago show room that while the second charger can be installed after you take delivery it would be more expensive.

I was advised that if I planed to take road trips to get the second charger even if I did not get the HPWC because more and more Level 3 public charging stations are going online and those would require the dual chargers to get the increased charging speed.

I have not yet ordered mine but based on this advice I am considering it as the cost to get it install at build is significantly less then after delivery because you do not need to pay for labor to install it.

nbw13462530 | 14 giugno 2013

If you don't have a High Power Wall Charger the twin chargers are useless. In addition, the supercharging stations do not use the on-board chargers. The twin chargers might be useful if you found an 80amp circuit to plug into, but I don't know of any public stations that provide that.

I hope that helps.

Tâm | 14 giugno 2013

There are 80 amperes around but it's hard to find out which:

Vicelike | 14 giugno 2013

Thanks for the clarifications. Very helpful. I am thinking if I have my home wired for 240/80 amp, I can use the Twin on board w/o springing for the fancy charging station in my garage.

Does that make sense?

ajamison | 14 giugno 2013

vicelike currently there is no way to have the car draw more then 50amps without a HPWC from home unless you get an after marker level 3 charging station

Vicelike | 14 giugno 2013


Let me see if I got this right.

Since I can comfortably live with a 31 mile per hour rate of charge which I can get from a 240/40 configuration and road trip recharge rates from the Super Charger stations are unrelated to whether or not I have a twin configuration on board, there is no good reason to go for the Twin or the Fancy charging station extras, given how I expect to use the car.

Thanks for the advice people.

AmpedRealtor | 14 giugno 2013

@ Vicelike, keep in mind that without twin chargers on board, you will not be able to take advantage of higher capacity J1772 chargers that are currently being installed in some portions of the US. These chargers can supposedly go up to 100A, but without twin chargers you will not be able to exceed 40/50A. Only time will tell how pervasive these new J1772 chargers will be.

AmpedRealtor | 14 giugno 2013

Following-up on that last post, I also don't believe that Tesla has any adapters that would work on the J1772 "combo" plug that would be required for this type of charging station. It's affectionately referred to as a "frankenplug" online :)

Jewsh | 14 giugno 2013

For the price of the second charger in relation to the entire car I can't imagine not having it installed. My wife and I sometimes head to Yorkdale where there is a Tesla store, and hence an 80A charger. We've charged the car from nearly empty to full over lunch and a short shopping session. It's very convenient to have dual chargers!

Tâm | 14 giugno 2013


You got it right BASED on your past history. There’s a saying:

"Past Performance is Not Necessarily Indicative of Future Results"

Which might be applicable to your case.

Owners after owners have been reported of their change in driving habit. They suddenly got a “Tesla grin”. They suddenly drive much much more than they used to.

After you finalized with your single charger, pray that you won’t get bit by Tesla bug!

Don’t worry, if you do, just pay a little more in money and installation time for the cure :)

mrspaghetti | 14 giugno 2013

Excellent point, Jewsh

DouglasR | 14 giugno 2013


You asked a similar question in another thread, but here is the answer I gave there:

The second charger is $3,600 plus tax, installed, when you add it after delivery. I believe it is $1,500 when you order it with the car. Hademarco is not correct. There are lots of 70+ amp public stations that make road trips much easier with the twin chargers, depending on where you live. You can find them from Vancouver, B.C. down to San Diego on the west coast (, and from Vancouver to Nova Scotia across the southern tier of Canada ( There are also a handful scattered elsewhere around the country.

@jrkbob1975 and AmpedRealtor are wrong: there are plenty of public stations that deliver power at 70+ amps, and for the J1772 stations (e.g., Clipper Creek CS-90), you do not need anything other than the J1772 adapter that comes with your car. For the Roadster stations, you do need a special adapter, but you can buy or borrow one. Whether you will use these high amp stations depends a lot on where you live and where you intend to drive. I drove from Seattle down to the SF Bay Area, and the trip would have been much more difficult without the twin chargers.

DouglasR | 14 giugno 2013

One other point: you will NOT get 31 rated miles per hour of charge with your 240/40 configuration. Count on around 24-29. That is because, first, the 31 mph rate advertised is based on "ideal" miles, and is not very realistic; rated miles will be lower. Second, your home outlet will not likely maintain the full 240/40 current throughout the charge.

In short, if you think the Superchargers can be used for EVERYWHERE you want to drive, and if you are happy with 24-29 mph charge rate at home, then don't get the twin chargers.

If you live or drive near high amperage stations (west coast, southern Canada), or want to drive places without superchargers, but with high amp stations, or want to take advantage of future installation of high amp stations, or want faster charging at home, then get the twin chargers. Also get them if $1,500 doesn't mean that much to you.

Brian H | 14 giugno 2013

One EE ("Peter7") even rigged up his own Multi-Input EVSE so he could use 2 14-50s at once at RV parks.

Car-El | 15 giugno 2013

Singel chargers will charge up to 10kw, so if you come across that can provide you with 12kw or 16,5kw your car can only charge with 10kw. If your car have twin chargers you can get use of power between 10kw-20kw.

TFMethane | 15 giugno 2013

There are standard J1772 plugs on many charging stations. Not just the "frankenplug" that is currently in development to accommodate true "level 3" charging. "Level 2" charging is actually a large range of voltage/amperage combinations.

I have used the standard j1772 plug on a charging station in San Luis Obispo to charge at 240V AC and 70Amps. That's basically the same as a high-powered wall connector.

So, for road trips where there are no superchargers, you may come across a particularly good J1772 charger that will give you quick juice.

However, most of the J1772 chargers out there are the minimum required to call it "Level 2:" 30 Amps, 240V. That is the same as my old dryer plug in my garage. There is no incentive for these electric charging networks to put in the better "Level 2" stations, since they charge you by the hour. Most electric cars can't even take advantage of the higher charging rates. So, they spend extra money to accommodate only a small number of people, who charge quicker and use more electricity in less time and pay them less total.

I would say, get the twin charger if you ever plan on going on a road trip, or if you ever plan on putting the HPWC in your house. Bear in mind, like someone here said, you'll get bitten by the Tesla bug. It's so much fun to drive, that you'll want to drive it everywhere and in all situations.

I would jut get it. And I did.

djm12 | 15 giugno 2013

Money would be better spent elsewhere

AmpedRealtor | 15 giugno 2013

@ DouglasR, thanks for the correction. I did not know that the standard J1772 connection could go up to 70A. That is great news! I'm assuming any higher (i.e., 100A) would require the new combo connector. So clearly there is an advantage to getting the twin chargers if you encounter a 70A charging station in the wild. Also, the Tesla Store here in Scottsdale has two Roadster chargers in the parking lot that are free to use. Are those going to be more than 40A?

PatT | 15 giugno 2013

If you plan to charge on the go, having twin chargers is a must. Super chargers will never be everywhere. Level 2 chargers currently go up to 100 amps. More and more of the J1772 chargers put out 70 to 90 amps and they are becoming the norm in Canada. There are also a lot of roadster HP chargers available that put out 70 amps (you need an adapter to tap into those). Spend the $1500 now and save the extra cost of the upgrade later when you realize you have better things to do with your time.

AmpedRealtor | 15 giugno 2013

I also suspect that when it comes time for resale, this will be a question asked by prospective buyers. Remember, if Tesla, Nissan and others are successful we are going to see higher amperage chargers pop up like weeds. If that happens, a few years from now you may regret not having the twin chargers in a resale situation when that may be a desirable feature to have.

DouglasR | 15 giugno 2013


I agree with you that there is little incentive to upgrade most existing commercial public charge stations to 70+ amps. However, when new stations are installed, the cost difference is not that great. And while many commercial networks are paid by the hour, cars that support higher charging rates are likely to avoid slower stations altogether in favor of faster ones, so there is certainly an incentive to install faster equipment in the future.

More important, many new installations are organized by enthusiasts who are interested in supporting the widest range of vehicles possible. For example, Plug-in North Central Washington is in the process of installing high amperage level two stations ("hal2", or in this case, Clipper Creek CS-90 units) in tourist areas throughout the north central part of the state, as well as electrifying Highway 20 across the North Cascades. They have already secured their first three units, and have entered into contracts with the host sites. Similarly, a project is underway to place a hal2 unit in Port Angeles on the Olympic Peninsula.

As much as we would like to see superchargers everywhere we want to travel, I simply do not think that is possible, at least not in the near future. There are many popular routes and destinations that will not be served by superchargers. Both commercial networks and groups promoting EV and economic development will step in to fill the gaps. Given the popularity of the Model S and the projected growing use of the TM drive train, I anticipate that we will see many more hal2 stations in the future.

DouglasR | 15 giugno 2013

As @PatT says, the J1772 standard supports up to 100 amps and uses the existing J1772 adapter. Clipper Creek also makes a CS-100 J1772 station. However, for some reason, the CS-100 is now limited to 75 amps rather than the expected 80, while the less expensive CS-90 supports 72 amps (80% of 90). Moreover, there is a glitch in the Roadster that does not allow it to charge at all if it senses a pilot signal in excess of 72 amps, so the Roadster cannot use the CS-100 unless it is further stepped down to 72 amps. For this reason, the CS-90 is the station of choice. It supports all vehicles (including the Roadster), and it gives you a charge rate almost as fast as an HPWC.

hademarco | 15 giugno 2013

How does a 90 amp charging station work? Wouldn't you need 2 cords to utilize the twin charger on the car?. Do these stations have 2 cords? If never been to a charging station so I don't know.

DouglasR | 15 giugno 2013

@hademarco, No, it uses a single cord with a J1772 connector. It looks like any other J1772 station, and works the same way in the car. The twin chargers are internal, and share a single connection. The only way you can tell that you have twin chargers is to try charging on a high amp station, and see that the rate is higher.

txjak | 15 giugno 2013

One other consideration, if you're needing some juice in a town with a Tesla Store or a Tesla Service Center, they have HPWCs or Roadster wall chargers with a adapters for the Model S.

In Austin, the HPWC at the Service Center is only available during business hours. The HPWC and Roadster chargers at the Store (Gallery) are in a parking structure and available 24/7.

stevencoberly | 15 giugno 2013

Sorry for what is probably a question with an obvious answer to many of you but here goes. Can I use a Tesla store's HPWC to charge my Model S if I do NOT have twin chargers? I think the answer is yes, but I just get a slower charging rate. Is that right?

Tâm | 15 giugno 2013


Your answers are correct. Single charger car can use high amperage HPWC at Tesla stores. Yes, its maximum rate would still be single, not twin chargers. Yes it'll be slower.

So pay up a little at the time of order for twin speed or pay up a lot in money and time to upgrade later when you want to save charging time in future.

dortor | 15 giugno 2013

I think a lot of confusion about twin chargers is the name - they are _NOT_ chargers - they are converters - they convert AC current to DC current…(so yeah they are chargers in that the DC current charges the battery)

1 converter can handle up to 40 amps (~10,000 watts)
twin converters can handle up to 80 amps (~20,000 watts)

more watts = shorter charging time

however (as has been mentioned) twin converts do no good what so ever if the source is less than/equal to 40 amps - which is the _MAJORITY_ of existing chargers - twin converts do not "upgrade" the power source.

in the future there may be an infrastructure of > 40 AMP chargers, but today that is not the case.

it is also important to note that when using the mobile charger (that comes with the tesla) it is limited to 40 amps max - so twin converters play no role when charging with the Tesla Mobile connector.

the only reasons to get twin converts is:

a) you plan to install a Tesla HPWC in your home and put it on a > 40 amp circuit
b) you plan to use Tesla HPWC units that are on a > 40 amp circuit
c) you plan to use roadster chargers that are typically 70 amp circuits
d) you want to "future proof" your car cause you believe strongly there will be a wide range of > 40 amp chargers available to you in your daily life

regardless of your needs - I believe it's unlikely high amperage J-1772 chargers will be come the norm…

as has already been mentioned the twin converts play no role in super charging and therefore are irrelevant.

so the purchasing decision IMHO comes do to the following question:

how often are you going to encounter a > 40 AMP charger - and if you do encounter a > 40 AMP charger how frustrated will you be that you only purchased a single charger.

in my one year of owning an EV in california I have only encountered/used 1 > 40 AMP charger - and it was the roadster charger @ harris ranch I used while I was waiting for the single superchargers to become available…of the 85 different chargers all over california I've used in the past 12 months that was the only charger that was greater than 40 amps (other than super chargers)

I believe it's also important to note that twin converters are still quite a bit slower than superchargers, and you're still effectively talking "overnight" to do a full range charge of a depleted tesla - a 100 amp Tesla HPWC still take 5 hours to fully charge a 85 kw Model S - and if I'm traveling that means I'm probably there overnight and the difference between 5 hours and 10 hours may become moot if I'm sleeping during that time any ways…

hademarco | 15 giugno 2013

Oh my gosh ....I thought twin chargers also meant an additional charge port ...doh! Thanks for all the info and clarification douglasR and dortor. This forum is such an excellent source of info.

PatT | 15 giugno 2013


I guess I disagree on two of your points: While you can call them converters, most people, including TMC call them chargers. They certainly convert AC to DC and the DC current is what charges the batteries. But if you want to order two converters for your MS, Tesla will expect that you will ask for twin chargers.

I live in Spokane in eastern Washington State. I've been driving Tesla EVs for three years. I started with a roadster. The charging infrastructure on this side of the Cascade Mountains is practically non existent, even now. Getting to Seattle from Spokane involved at least four hours of sitting around an RV park. It also made round trips from Seattle to the east side of the state iffy at best. About two years ago, an EV enthusiast )Tom Saxton) got a roadster HPC put in in Ellensburg. That changed the four wait to a two hour lunch. Since getting my MS (twin chargers) I have used that connector twice and with the MS I only need a 1-1/2 hour lunch.

I have also taken a trip to Las Vegas in my MS. I love using the SC at Harris Ranch and at Barstow but to get to those locations I used four roadster HPC without spending the night at any of them -- just long lunches and/or dinners. Besides the Ellensburg unit, there were three on I-5 -- Centralia; the Four Feathers truck stop in southern Oregon; and the Berry Patch north of Sacramento.

This summer I plan to take some road trips into Canada. I know of four of the higher amp J-1772 that I plan to utilize on those trips.

The trick is to plan your trip carefully knowing that you'll be charging fully overnight. During the day you only need to take on enough juice to get to the next lunch stop or dinner and make sure that you can get those electrons as fast as possible. Twin chargers are just the item that makes planning easier and when you're already putting out $100k, the $1500 is insignificant, IMO.

Mark K | 15 giugno 2013

Unless the $1.5K is material to your purchase, get the twins. We use them all the time.

DouglasR | 15 giugno 2013

@PatT - You just deprived the Canyonville stop of three of its feathers! :)

I'm probably repeating myself here, but this past February my wife and I drove from Seattle down to the SF Bay Area and back using ONLY 70+ amp stations. The trip took two days each direction, stopping for an hour or so at the less-interesting places, over four hours in Portland where we visited friends, and overnight at Seven Feathers Resort (where a 30 amp station would have worked just fine, but we used the Roadster station). Without the twin chargers, the trip would have taken at least three days each way. Think of it as the difference between being able to log 300 miles in a day versus 400 miles in a day (not too different from having a 60 kWh versus an 85 kWh car).

The "Tesla Highway" of high amp stations runs from Vancouver B.C. down to San Diego, including some areas not on I-5. In Canada, high amperage stations probably outnumber <40 amp stations, which is quite convenient for those of us in Seattle. So these stations are not as rare as @dortor would have us believe. And I think we will be seeing more of them. For me, the added flexibility of charging at 72 amps is well worth the extra cost.

Vicelike | 15 giugno 2013

Thanks to all for your thoughtful comments on this subject. As a prospect who knows next to nothing about electric car recharging, you have gotten me to the point where I can make an informed judgement.

After reading all your comments, I have changed my mind and am ordering the car with the Twin Chargers.

Although 95% of the time it will be unneeded, that other 5% will drive me crazy cuz the only thing I hate more than being wrong is waiting in line.

Plus as some of you pointed out, the pace of technical innovation is likely to change the utility of the faster charge. By the time I am ready to sell,the single might be like having a dial up modum!


CC | 15 giugno 2013

By the way, the on-board charger is NOT 10-20 lbs as someone mentioned earlier on the thread. I had the opportunity to hold one in my arms 3 month ago while picking up my S at the service center, it is pretty heavy, at least 50 to 60 lbs. So having twin chargers, you are adding about 120 lbs to the car. FYI.

DouglasR | 15 giugno 2013

@CC - Well, if it is 60 lbs, then you are adding 60 lbs. All cars have one charger. The question is whether to add a second.

CC | 15 giugno 2013

Right, 60 lbs per charger, so adding the 2nd charger will add 60 lb to the car, and a total of 120 lbs (both chargers).

I went with single charger. Figuring in 5 years, Tesla may come out with a higher, more efficient charger and by then there may be more public chargers out in the wild with greater than 40 amp and higher voltage. May be at that time I will add the 2nd charger :) So for the mean time I save $1500 (used it to buy some Tesla stock 4 months ago), and save some weight...

dortor | 15 giugno 2013

oh and in the interest of full disclosure - my P85 has twin chargers - I fall into the category that I would be severely frustrated to be sitting at a high-amp charger and going slower than I otherwise could…

that being said

a) I have yet to encounter a large number of high-amp chargers
b) this is the one thing I would reconsider if I were to build again

so far the $1500 has been mostly wasted given the lack of high-amp chargers - this may change in the fullness of time…

michael1800 | 16 giugno 2013

You could attempt to check PlugShare, Recargo, Chargepoint, Blink, etc to see if there are any high-amp chargers near you (or on your potential trip routes), but sometimes the amp info is there, sometimes not (plugshare is pretty detailed in my area).

I hear New England, Cali and Canada have a lot of them, but in my case, there aren't any that are remotely close to me (NW Florida). YMMV, but if you don't often take trips -and- there are none listed along the path you take for trips, it seems like a big gamble. If the SCs deploy as projected, your 5% problem should be addressed without the twins.

Everyone else is right...higher amp charge points could pop up anywhere and at anytime, but I think the SCs will become more proliferated sooner than high-amp level 2 EVSEs. Seems like a waste of 1.5k.

That said, I bought the twin chargers. I'll let you know how it turns out in 3 years.

LMB | 30 giugno 2013

(LMB spouse) Sorry to wake up this thread. Does anyone know if the 70 amp J1772 chargers will charge a Model S with a single charger at 40 amps versus the usual 30 amps from a "standard" J1772 unit? Has anyone tried this? Thanks.

Bighorn | 30 giugno 2013

It should charge at 40 amps vs the, I think, 24 amps you'd normally receive from a 30A outlet (80% rule).

LMB | 30 giugno 2013

(LMB spouse) Thanks. I'm not referring to a 30 amp outlet like a dryer, but rather a "standard" 30 amp level 2 J1772 charger versus a 70 amp J1772 charger. Does the latter charge a non-twin-charger Model S faster than the former?

Bighorn | 30 giugno 2013

@LMB's wife
I would say 2/3s faster, if my math and assumptions about current level is correct.

Brian H | 30 giugno 2013

To put it another way, for every 5 minutes the 30-amp (actually delivering 24A) takes, the 70A (actually delivering 40A) should take only 3 minutes.

CarlE_P439 | 2 luglio 2013

I have Twin Chargers and have needed them given the necessity to charge on several occasions at a (non- Supercharger) Tesla charger in the Natick Mall that delivers 60 amps.

tonysled | 4 luglio 2013

I would go with the twin on-board chargers and the HPWC for your garage. Charging time is reduced but you have to make sure you have room in your electrical box for it. I had a 100 amp service put in that used to charge at 80 amps which allowed for a quick charge when necessary, roughly a mile of charge per minute at 80amps (before Tesla reduced it to 60 amps max for an issue that apparently is not corrected yet. However I have every expectation that they will come back with a fix so we can get back to charging at 80amps soon). The superchargers bypass the on-board chargers altogether so single or twin is not an issue if you are a lucky person that has access to superchargers.

Brian H | 5 luglio 2013

each time you charge you can re-select 80A on the touchscreen. Occasional fuse problems with a few units probably don't affect you.

tonysled | 5 luglio 2013

BrianH. That doesn't work as the current software releases limits the charge rate to 60amps max no matter what setting above 60 you select. If I set it at 80amps, the charge rate will not exceed 60amps (the charge screen will never exceed 60amps)even though I am set up for 80amps. Tesla did that since they cannot directly control the settings on the wall charger itself which is where the issue is. You (or your electrician) set those switches manually so they had to limit it through the software to make sure people would not "forget" to limit their wall connectors to 60 amps. Tried that trick already and verified through customer service it wouldn't work.