High Power Wall Connector/Twin Chargers

High Power Wall Connector/Twin Chargers

I just want to make sure I understand this correctly. I'm getting the 40kWh battery and I want the twin chargers. If I have the correct 240 volt outlet I can charge at about 31 miles per hour of charge. If I get the twin chargers I can get about 62 miles per hour of charge. I do not need the High Power Wall Connector for this. It will also allow me to charge at public charging stations at the same rate. Is the High Power Wall Connector for convenience and cosmetics but will not make the charge faster?

Anybody have any idea what the LIPA cost of electricty on Long Island is? I called them and they said it's around 8 cents in the winter and 10 cents in the summer. It sounded too good to be true.

Thanks for the help.

Chuck Lusin | 3 December 2012

That sounds like it might be right, I can see my rate on the bill.
PS: the 40KWh battery should get about ~ 125 miles, the hpwc will reduce your charge time from 4 hours to 2 hours. Are you sure the you will need it?

David M. | 3 December 2012

With a combination of the 40kWh battery, no twin charger, and a 240V NEMA 14-50 outlet, you will get a max 31 miles per hour of charging. If you had the twin chargers, along with a 100A circuit (charges at 80A), you could get up to 62 miles per hour of charging.

Virtually all public charging stations are 240V, 30A, so you will max out at 18 to 20 miles per hour of charging regardless of whether you have the twin chargers.

Most utilities charge between 8 cents and 14 cents per kWh for electricity. You can tell from your electric bill.

dorseka | 3 December 2012

Do you mean two hours with the twin chargers and not the hpwc?

David M. | 3 December 2012

Having the Twin chargers just represents the ability to ACCEPT a higher rate of charge, in and of itself it doesn't make it so. You will also need a circuit supplying dedicated 100A to the HPWC in addition to your twin chargers.

I've never heard of someone getting the 40kWh battery who thought they needed the HPWC unless they just liked the look of it.

dorseka | 3 December 2012

Thanks David. I was think of the twin chargers more for public charging than home charging. If it doesn't help for public charging then I don't need it. Thanks for the info.

Ceilidh | 3 December 2012

No. You seem to be confusing things.

The HPWC will allow car equipped with twin chargers to charge at up to 62 mph under ideal conditions. Most will see charging rates slower than this, but more than a 50 amp wall outlet, such as a NEMA 14-50.

With twin chargers and a 14-50 wall outlet, without the HPWC you would get up to 31 mph per charge. Likely a little less.

With a single charger and a HPWC you get up to 31 moh per charge.

Eith a single charger and a 14-50 outlet you get up to 31 mph per charge.

If you are not getting the HPWC the utility of twin chargers is to take advantage of high amp chargers when you encounter them in the wild. However, at this time most public J1772 chargers are a pathetic 30 amps, at about 15-18 mph of charging.

However, the J1772 standard can accommodate up to 80 amps and you may run into some. If you do you can take advantage of the 30 amps more than a single charger configuration would allow you to utilize.

So twin chargers help with the HPWC or high amp EVSEs in the wild to shorten charging times. The latger your battery the more critical this is, and the more frequently you dive long distances the more critical this is.

I hope that clears this up some for you.


BYT | 3 December 2012

"If you had the twin chargers, along with a 100A circuit (charges at 80A), you could get up to 62 miles per hour of charging."

This is my exact setup, two 50amp circuits that the Twin Charger plugs into but I my Model S keeps jumping down to 40amps instead of the rated 80amps. Is this a call to Solar City to fix or Tesla Motors?

David M. | 3 December 2012

One more item to consider. As Tesla continues to roll out the Super chargers, a 85kWh Model S or even a 60kWh Model S can charge at a much higher rate than a 50A circuit provides (even without dual chargers) because the Superchargers are DC (instead of AC) and therefore bypass the "in car" charger(s). A Model S with the 40kWh battery cannot make use of the Superchargers.

So, if you have extra money for upgrades to the Model S, you should consider upgrading to a bigger battery and getting the ability to use the SuperChargers.

bfranks273 | 3 December 2012

Hi BYT, what do you mean you have two circuits that the two chargers plug into? Your car has a single cable to single plug. If its like a 14-50 then you get 40 amps out of the socket, no more. Describe the two circuits and your hookup. if you mean you have two circuit breakers, yes, they are ganged and you can pull 50 (40 really) out of each side at a total of 240 volts across them. You need 100 amp service to take advantage of the twin chargers.

BYT | 3 December 2012

Damn, so the fact there are two of them, 50amps each, doesn't mean it will draw up to 100amps across the two? I don't get what "twin chargers" means then?

Chuck Lusin | 3 December 2012

The car has only one plug, so you can charge from 1 to 40 amps with a single onboard charger, or between 1 to 80 amps with the twin chargers. If you are getting the twin chargers, you would need the high power charger, and one 100 amp breaker to feed the charger. If you have two 50 amp breakers that will to be changed to one 100 amp breaker and you will also need to change to a thicker wire gauge. With two 50 amp breakers, you could charge two cars at the same time.

jat | 3 December 2012

@BYT - the twin chargers means inside the car there are two chargers that converts the supplied AC to the DC needed to charge the batteries. Each one is capable of handling 10kW of power (~42A @ 240V). If you only have a 50A breaker (it gets derated to 40A for continuous loads >3hr), then you can only utilize one of them.

Personally, I expect to very rarely make use of the extra charging rate (my LEAF charges at 3.3kW but virtually all of the charging is overnight, so I don't care that it takes 7hr), but I plan on getting the dual chargers just in case, and the HPWC because I want the convenience of not having to use the mobile power connector (I can just plug the cable in, and when I am done hang it up on the wall). It isn't a lot more than I could get another J1772 charger for, and then I will have the higher charge rate if I do ever need it -- about the only time I could imagine it would be needing to run some errands right after getting back from an out-of-town trip.

Ceilidh | 3 December 2012

twin chargers = greater capacity to draw from 1 plug.

murraypetera | 3 December 2012

The smaller the battery the greater the need for a quicker charge. If you arrive home depleted and want a quicker turnaround you will need the twin chargers and HPC. If you are fortunate enough to have a higher current J1772 or a tesla store on your route the twin charges will be great to have cutting your wait time in half. .

One would also hope Tesla puts HPC chargers at their new Super charging stations since the additional cost for them would be negligible but the customer satisfaction would be great.

Chuck Lusin | 3 December 2012

Remember that Super Charging is not available for the 40’s. You will only need the twin chargers and high power wall connector if you need to full charge in 2 hours. Most people here would say to spend the $2,700 on other things first. ChargePoint is quite popular, but only charges at 240V and 30A 7.2kW is can be handled by a single onboard charger.

DouglasR | 3 December 2012

I wish I had configured with twin chargers but I do not want the HPWC. There is plenty of time to charge at home. I would like the twin chargers for road trips Seattle to California. There are a number of 70 amp Roadster chargers along that route, and the superchargers won't be operational for a couple of years.

dan.pickerill | 3 December 2012

LIPA rates vary with different classes of use. If you go to this website it defines how the charges are calculated.

petero | 3 December 2012

I was under the impression that the twin chargers could be added by a TM Service Center if you decided later to upgrade. Yes- No- Maybe?

Brian H | 3 December 2012

petero, DouglasR;
The second charger can be added anytime, but I think the cost is not yet known.

Timo | 3 December 2012

Supercharger is one that can't be added later. I think that is pretty much the only thing that can't.

DouglasR | 4 December 2012

Yes, I'm looking into adding second charger now.

Criscros32 | 18 March 2013

Near my house 2 drops to houses have turned bright blue this month; the black insulation has melted and the neutral bare melted after contact with the coper strands in the exposed black(s).
Both homes have added a 100 amp service for a twin charger that runs at 80 amps in the car.
The house power head in both homes is not damaged nor are any wires in the houses; a few liter were on with the tesla at the time, but a few hours earlier more stuff was using juice.
My question pertains to the single phase auto transformer 240 with neutral used by the small box on the wall and what the car is doing with the single phase power: does it use the 240 secondary autoxfmr w/o the neutral ?
Does it use 120 v to neutral in a unbalanced way? Does it do both?
The end result is the black 220 lines are both bad for a few feet where the big blue arc occurred. If most of the current went thru 1 black line, it makes sense why 2 homes power drops went pssht with a blue flash.
There are other folkes in the neighborhood w tooo much money buying the s model w all the bells and whistles;
Are more of them going to need a PGE repair?

dortor | 18 March 2013

Twin Charger can be added by Tesla - cost is $3600.00 after delivery - cost when you order the car is much cheaper -

Twin Chargers are only useful for charging systems > 50 amps - otherwise the advantages of the 2nd charger go un-utililized

Twin Chargers have no effect on super chargers since they bypass the car's built-in chargers.

At this point in time you should only get the twin chargers if you expect to do one or more of the following:

a) installed a Tesla High Powered Wall Connector along with a 50 AMP or _GREATER_ circuit - to really make it worth while 70-100 AMP circuit is suggested by myself, because otherwise the "increased" miles-per-hour of charger rate is in-consequentlal (37 miles of range per hour vs. 31)
b) you expect to encounter > 40 AMP chargers in the wild - this to date is rare - I personally in 6 months of EV roaming have never encountered a charger > 40 amps (most public chargers are 32 amp systems charging at 15-20 miles/hour)
c) charger frequently at a Tesla location where they have HPWC's
d) visit friends with > 50 amp & Tesla HPWC
e) upgrade your house/lifestyle in the future
f) be ready for future nirvana of a EV USA road system with Super Chargers and fast/free/100 AMP public chargers.

Twin chargers are not magic - they can't make anything charge at a rate faster than what is being delivered by the charger system you're using - they represent capacity should you use/encounter a high AMP charging system - so far the only systems i'm aware of are the Tesla HPWC, 70 AMP Roadster chargers (adapter required), and some mythical 70 AMP J1772 public charging stations (I've never seen/used one) - but I know there are ones that can be ordered and therefore there must be a market and they must be installed somewhere - I just don't know.

DouglasR | 18 March 2013


I drove from Seattle to the SF Bay Area and back using only 70 amp sources. I did it in two days each way, which I could not have done without twin chargers and the 70 amp sources. Also, you can drive across southern Canada from coast to coast using only 70 amp J1772 stations.

dortor | 18 March 2013

I agree that if you have 70 AMP sources twin chargers are a big advantage. But I still don't know where any are.

DouglasR | 18 March 2013

Mostly west coast of U.S. and southern Canada it seems.

DouglasR | 18 March 2013
dortor | 19 March 2013

cool! Thanks.

jdesmo | 19 March 2013

LIPA utility costs on LI are very expensive. Total cost all inclusive of taxes and other fees is $0.22/KWH. This is from my last home statement in Feb. 2013.
This also means, that if you want to calculate true equivalent MPG for the MS 85KW in NYC/LI area, you come to only 34MPG.
This is based on the following: $4.50/Gal, 84% charge efficiency , 124KWH vampire loss/month, 350wh/mi.

Jewsh | 2 September 2013

I used a Sun Country CS90 recently. Great charger - thinking of getting one for home in lieu of the Tesla HPWC... it has a more universal appeal in the off chance the our next EV doesn't use the Tesla plug type. (Who knows if Bluestar will change the plug, either... J1772 seems like a good standard for the moment other than for supercharging.)