Two High Power Wall Connectors?

Two High Power Wall Connectors?

Took my first test drive last week (S85) and had three distinct Tesla Grin moments:
1. 0-60 MPH
2. 50-80 MPH (this was the bigger grin. it's just so cool)
3. Total confidence when merging into traffic via the highway on-ramp.

I have been building all kinds of financial models to see if I can make a purchase work and think I'm there (will likely be next spring sometime after bonus season). One question I had for this forum is about having two HPWC locations installed at my home. We are a two car family with only a one car garage. There's a place to park in the driveway outside the garage and my wife and I often swap places there based on who gets home first. I was thinking to definitely install one HPWC in the garage but thought about adding a second somehow outside. Has anyone done this? Or, have you installed a 220v outlet outside and charged that way? Pros and cons to this approach?

We could always move the cars at the end of the day to ensure the MS gets the garage spot but want to think through solutions to charge in both places if possible.

Thanks and stoked to be a part of this community (hopefully soon!)

hamer | 1 settembre 2013

Unless you have a burning need to charge your car from near empty to near full in about 3 hours, you probably don't even need one.

The twin chargers will suffice in case someone else has one while you're on the road, or in case you come across a (rare) level 3 J7221 charger while on the road.

ir | 1 settembre 2013

The HPWC is weatherproof, at typical 14-50 connector is less so. Overnight charging with a 14-50 is more than enough in most cases. The HPWC is handy when you are in a hurry, so outside might not be a bad idea.

This whole thought experiment is for nothing if your house power cannot handle both. To be code compliant the electrician needs to calculate your power needs and make sure you don't exceed it. Since both outlets are "EV Chargers" they need to assume that they could be both going while you are hosting a holiday feast inside (oven on full, lights on, HVAC on max, laundry going, etc...

I too once had delusions of a HPWC (never mind +14-50) until my electrician pointed out that my house has a 125 amp feed that cannot be upgraded. :(

michael1800 | 1 settembre 2013

If you go the dual charger route (which is another argument in itself), having two HPWCs at home is unnecessary and would likely be unnecessarily expensive (needing to have 2 200A panels). Mount your HPWC in either location and simply have a NEMA 14-50 in the other. You only need a HPWC for times when you need a charge fast; most of the time, simply charging overnight works (7-8hrs). If paying a few extra thousand for the electrical work and extra HPWC is no biggie, then it doesn't really matter, but you likely don't need that level of convenience (The HPWC on the outside and NEMA on the inside of the garage pretty much covers most situations).

SUN 2 DRV | 1 settembre 2013

Consider taking this opportunity to convince the wife that the Tesla will always need to be the one parked in the garage, both for charging reasons and to prevent any possible vandalism to such a high value asset. Then you'll only need to purchase and install one HPWC.

barTok | 1 settembre 2013

Thanks all. @ir - we purchased this house a little over a year ago, there are two circuit breaker boxes in the basement. One seemingly connected to the other, if I were to add up all of the amps, it's well over 200. That said, I have no idea what I'm talking about so advice well taken and I will contact an electrician prior to purchase to consult on options & feasibility.

@ michael1800 - I actually like the idea of having the HPWC outside and NEMA inside if I go that route.

@hamer - good point, this will be for overnight charging mainly so maybe I can avoid the cost altogether.

@joehuber - good advice although I'm taking it one step at a time on the wife front. I'm playing the long game now just to convince her that we should buy this thing. Don't want to overplay my hand and push it too far with the garage requirement just yet. But will keep it in mind.

michael1800 | 1 settembre 2013

Unfortunately, you can't add up all the amps. You need to have a panel (a punch-out area inside the box) with a 200A breaker. For 2x HPWC, you need 2 of those. Most houses aren't able to accommodate that potential draw (as in the power coming to your house from the electric company). Like you stated (with an abundance if insight!), the electrician will give you the best info suitable for your particular house and panel setup. Good luck, and remember you can contact sales with technical questions and discussions prior to committing to a particular solution.

ColoradoBlueS | 1 settembre 2013

An alternate idea: Assuming you pull into the driveway AND garage facing forwards, then consider mounting the HPWC inside the garage, but adjacent to the roll-up door on the driver's side. This would allow the HPWC charge cable to reach the car when parked outside in the driveway as well. We did exactly this and it works fine as long as your garage door does not need to seal too tightly to the ground (the cable is pretty thick). I can supply pictures if it would help.

And while I agree that a NEMA 10-50 outlet is just fine for most folks, it is pretty easy to justify the HPWC if you have the amperage headroom to handle the load and you do not already have a 240 line of sufficient amperage already installed in your garage. Sounds like you're going to pay an electrician to install a line, so just make it a BIG line. You would be very happy if you did, especially if you opt for the twin chargers in the car. Charging at 60+ miles of range per hour is a very nice option. And I don't think anyone would disagree that the HPWC just looks super cool, especially when it is actively charging.

That said, if you are not getting the twin chargers, or do not have the amperage headroom, then perhaps installing the NEMA 14-50 in the same location I describe might also work for indoor AND outdoor charging (and be less expensive). I can simulate it with the mobile charge cable using our setup to see if it would reach if you would like, but I believe it would.

Best of luck. We picked up our S85 yesterday and could not be happier. For us, the Model S is a significantly more expensive car than any we have ever owned, so I can understand the mental wrangling about it. Let me know if there is anything I can do to help your cause.


Brian H | 1 settembre 2013

IIRC, the dual chargers and HWPC are now a single purchase, and you can't have one without the other.

Brian H | 1 settembre 2013

typo: HPWC

shop | 1 settembre 2013

What is the main breaker rating on each panel? On at least one panel, there should be a big breaker like 200a. It is likely the second panel just feeds off the main panel.

Keith72 | 2 settembre 2013

I went with the dual chargers so I'd have the capability for faster charging on long trips (if I could find a level 3 J7221 or a fellow Tesla owner with an HPWC along my route). I did not go for the HPWC because I didn't need to charge at 60 mph at home (and I'm not close enough to a major highway to be of assistance to other Tesla owners). I went with the NEMA 14-50 and the 30 mph of charge is more than sufficient for me. Even if you install the HWPC, you'll need to be able to stop by the house for top off to really take advantage of it. With the 14-50 you can buy a 30' extension cord rated for 240V at 50 amps for less than $100, and it works fine (so no need to have to tell your wife she's stuck parking in the driveway).

KendallPB | 2 settembre 2013

Two HPWCs? Even with two cars that can use them, not really needed. Consider. Let's say you get home at 6? 7? PM. Well, plug in your Model S; unplug before you go to bed and plug in the other Model S. Depending on your commute and who stays up later and when y'all go to bed, either you'd both leave in the morning with a full charge, or else one would leave in the morning with a full charge and the other with a mostly-full charge. You could swap who gets the longer charge. Most times you won't even need the full charge.

Of course, the way they package it, you'd need to have both cars with twin chargers AND HPWCs...but you could no doubt sell the second HPWC.

Just a thought. I got twin+HPWC (when they were packaged separately), planning for this type of situation, one of these years, if/when we replace my other half's SUV with a Model X or S or Gen III or what-not. We keep different hours, so swapping plugs will be no problem for me.

ian | 2 settembre 2013

@barTok - You didn't say how long your daily commute is. You could probably get away with the single HPWC in the garage and just charge every other day or whenever you get to park in the garage.


tes-s | 3 settembre 2013

I like the idea of one in the garage that will reach two parking locations, if possible.

Unlikely a house has enough existing service for two HPWCs - though you could probably have one circuit and a 100amp transfer switch to switch between the two.

Oliver in Seattle | 3 settembre 2013

We have the situation originally described by the OP, almost exactly (throw in a tandem garage for good measure and extra shuffling on the rare occasion that I want to dig out the Boxster and you are there).

I originally purchased the twin chargers with the intent of using suncoast highway CS 90 chargers, but was less than happy plugging and unplugging my mobile wall connector in the rain last winter and sprung for a HPWC when they became available. I don't really need the 80A charging (and can't use it since my HPWC still has the old fuses), but I sure do like the weather tight box better than the (somewhat covered) 6-50 box it replaced. We have a 6-50 in the garage for when we switch places.

I thought about the under the garage door approach, but if you have enough pressure to make a seal, I'm pretty sure that eventually you would damage the cable.

Just my thoughts....


Brian H | 3 settembre 2013

Seems like a setup for some really tense confrontations if someone forgets!

KendallPB | 21 settembre 2013

@Oliver: I run mine under the door. Tesla said it was fine; they driver heaver things over it than a garage door. No garage door is so heavy or seals so tightly that it would damage this heavy duty cable, methinks...but caveat emptor, of course--try it with someone else first, I suppose.

@Brian H: Not really; plugging in every night, missing a night won't matter. Well, unless your daily commutes is half or more of your range (ours aren't).

jat | 22 settembre 2013

Your house doesn't need to be able to handle both, because they wouldn't be in use at the same time - you don't even need any sort of transfer switch. Each would have their own 100A breaker, and if you ever did have them both on, you would just trip the main breaker with no further harm than the inconvenience.

redacted | 22 settembre 2013

@barTok, if you are considering whether you can afford the car, keep in mind that the HPWC is a $2700 accessory (including the dual chargers, plus installation - mine cost $400 more to install than 14-50) that is less useful than just about any other accessory you can get on the car. Except, I suppose, for the mood lighting.

bryceha | 22 settembre 2013

I agree with 'less is enough' comments above. If you are looking to save $$, and perhaps accelerate the purchase date, just use a 14-50 outlet near the door. Don't pay for extra for HPWC or twin chargers. A chat with an electrician is also a good next step. I'm guessing that installing 2 HPWC, let alone one, will add significant expense to your overall project.

Pungoteague_Dave | 22 settembre 2013

Correcting a couple of the comments above:

1) The HPWC is NOT weatherproof and must be sheltered if installed outside. It has sensitive electronics and no seals. I have had mine apart to do the fuse upgrade and found the cover to fit loosely and the edges are not sealed in any way.

2) You can still purchase the car with twin chargers and without the HPWC, although it isn't presented that way in the configuration page. You have to ask and they will do a delete before you finalize.

3) The HPWC is not always a useless accessory as stated above. We have two HPWC's, one at each home, and find them invaluable, but it depends on how you use that car. Most owners don't face this need often. However, we drive 190 miles each way between our homes every week. When we drive in the morning, it is great to refill the empty battery quickly so we can still use the car for local driving in the afternoon and evening. When we take the trip in the evening, the HPWC is no better than a 1450 outlet, as the car will fully charge overnight using either method.

The recommendations above on putting the power supply (either a HPWC or a 1450 outlet) near your garage door are good - both the HPWC cable and the standard charging cord are long enough to reach the back of the car from the front if parked inside, and under your closed garage door if left outside.