Receptacle Roundup IXb: Tesla S

I mentioned the first Tesla plug, for the first Tesla car. It’s basically SAE J1772 2009, and basically got superseded by that widespread connector standard. Tesla then offered the Model S, with a Model S connector. (Well, two actually, on each side, but of the same design.) Will this one fare any better… especially since it now competes with CHAdeMO, as well as J1772?

p105078dp105052bThis time, an adapter easily matches up the pins with J1772, and the S-connector in some installations matches CHAdeMO’s capability. That’s right, one standard will accept both Level 2 charging (240V, medium-speed AC) and ~1 hour Level 3 (from a 480V fast-DC “Supercharger”). A cord with an inline power brick will also allow Level 1 trickle charging (household 120V AC)- all three levels and speeds through arguably a single interface.

The Level 2 is easiest; it’s basically J1772, with the same number of pins but of later, better designs. Since the pinout and signal protocols are the same, all it takes is a mechanical adapter to “change” one layout to the other. Tesla sells a small J1772-to-S adapter, for multi-hour public charging; it’s a simple sleeve that goes over the “tip” of the public cable. Once Level 2 charging has been settled, feeding Level 1 power (for overnight charging) is straightforward; a brick handles the protocols, as J1772 was designed to go down to these household voltages and currents. This is how every other modern EV maker now does the L1-to-L2 mate.

What every other automaker doesn’t do is Level 3, through a compact plug. Sure, the SAE CCS (Combined Charge System) “Combo Plug” uses J1772, but only by adding two extra, outer pins for the DC lines. Tesla uses the existing Level 2 connector design, unmodified as far as the car is concerned. With this, a Tesla “Supercharger” can deliver ~90 kW, with a promise of 120 kW in the future.  This will mostly recharge a Model-S in about an hour. It’s effectively the same feat as CHAdeMO, except Tesla battery packs are two to three times as large as Nissan/Mitsubishi packs… quite the feat.  Meanwhile, the plug is a fraction of the size of CHAdeMO, with half the pins in a more-rugged design.

Your home cannot support a >400V Tesla charger; it’s the same deal as CHAdeMO or any other Level 3. Industrial sites are needed, with 3-phase industrial power at high currents. Unlike CHAdeMO, which is handled by third-party sites and networks, the Tesla Superchargers are by the OEM. Tesla maintains the network, using solar canopies at some, and is promising free charges for Model S owners in perpetuity.  That’s right, free charging forever.

The Supercharger network spans between city pairs, along the Interstate system.  Rural points form corridors; in California, the I-5 corridor is how one naturally drives between the Bay Area and Southern California.  There are also Barstow and Folsom Superchargers, for travel to Tahoe and Las Vegas.  On the East Coast, Superchargers are on I-95 in Delaware (between DC-Philadelphia) and Connecticut (between NY-Boston). Neither are solar. Note that there is no NY-Philly Supercharger, since most Model S’s can do that trip easily. The beauty is that these two placements do the job.  Each site has multiple chargers, so there have to be a fair number of Model S’s meeting before serious contention occurs. At well over US$60,000 for the 60-kWh Model S, reaching up to $100,000 with all the extras, there aren’t that many on the roads, let alone on the same Interstate at the same time… yet.

Ultimately, Tesla claims it will cover the United States with enough sites to allow cross-country Supercharging.  Of course, drivers of Nissans and Mitsubishis can’t use the company’s Superchargers. That would defeat the selling point of Supercharging and Tesla’s Model S. But neither will the base Model S, with its 40-kWh battery pack.  That won’t let you span between these sites, and won’t justify the network’s usage model.

Note, however, that these do not represent any vendor lock-in: the ability of a manufacturer to shut out third-party vendors. That’s an anti-EV talking point that’s been going around.  CHAdeMO cars are manufactured by multiple companies, none of which can take over the standard; similarly, CHAdeMO installations come from AeroVironment, Eaton, Fuji, etc. While Tesla Supercharging appears to be proprietary, the Model S, Leaf, Zero, Volt, etc. can also take J1772 and household Level 1. Tesla is about to release a CHAdeMO-to-Model S adapter anyway; CHAdeMO-to-SAE CCS adapting is also practical and incoming in at least one form. SAE CCS-to-Model S is even easier, like J1772-to-Model S. (The CHAdeMO adapter is for Japan- market Teslas, and may or may not be offered to other owners. It’s also not clear how much the adapters will be.) Thus, your vehicle can never truly be hamstrung by a single vendor. The clear majority of EV charging is actually done at your own home, and no one is tiptoeing in the night to install some weird receptacle in your driveway, unnoticed. Should some newer, more-advanced connector appear tomorrow, all EV makers would study it, too, and the possibilities for their adoption of it.

What is noticed is the Tesla battery range, and the serious enabling capability that a long range plus Level 3 charging will give. EV range is now at the point where the trip is often limited by you, not the battery. An 85-kWh Model S can keep driving until your next mealtime, and/or major bathroom break. If you then need to stop anyway, why not feed the car as well as the stomach?

And, of course, this is assuming you’re on a serious road trip- the majority of people, the majority of the time, are commuting three to eight miles. Here, use of a 40-kWh Model S is already transparent; an 85- kWh model with Supercharging capability might as well be a train (but with no bathroom).

There are issues, of course- no rollout is expected to be perfect. The all-metal shell is rugged. However, some Model S owners report sticking connectors. I can’t yet tell which reports are tight clearances and substandard quality control, and which ones are firmware bugs causing latch- release failures. Unlike gas nozzles, the Level 3 charger interfaces all have a mechanical locking feature; Tesla’s design actuates via servos and software. That button you see? It’s not a mechanical release. It’s an electrical switch; pressing it tells the car to stop the charge (possibly letting stray voltages dissipate), then unclamp the plug. p105085bIt takes a finite time to complete all steps; drivers accustomed to gas nozzles may simply be being impatient. Both manufacturing clearances and software hangups would be failures of implementation, not of the connector design- later Model S units and/or later software builds may take care of this with proper diligence on Tesla’s part. Being impatient? We’re all guilty at times.

And site contention has happened. Lightning does strike, and by pure chance five people will occasionally show up to a site that has four Supercharger units. Even in the case of four people at four, the fourth person gets a slowdown in charging, as the site tries to limit surge power. If Tesla wants to keep up the ad claims and the user experience, they are under pressure to add Superchargers to existing sites. The Tesla factory is already capable of producing over 20,000 units per year; if they actually hit that, the existing sites will then urgently need eight, twelve, or more Superchargers each.

Speaking of contention, electrical draw contends with the neighborhood power grid as well as with the other Model S drivers on site.  One of the costs of these sites is demand charges.  These are the premiums electrical utilities will ask, if you are likely to pull a huge load during the day.  Utilities want to discourage power spikes (and encourage night/weekend load), and they discourage them through the pocketbook.  This is the immediate reason why some Supercharger sites use solar canopies; the Sun happens to be out in the day, when utilities are racking up these demand premiums.  At least, the Sun is out in California, not necessarily Connecticut.  I imagine that Tesla is simply swallowing the premiums on the East Coast.  Another reason is that Tesla is partnered with Solar City, a PV installer, so the panels can go up without two companies trying to get a cut.

Digging low, Tesla has the bad habit of placing their charge ports at the rear of their cars. Short cables or poor locations may require you to back into a Supercharger or J1772 parking stall. As EV issues go, this is an issue I’d be willing to put up with… for $60,000 you get a back-up camera, of course.

Tesla Model S/Supercharger Plus
-Brutally faster than household 3-prong: about 60x more power
-High power now allows roadside charge stops, a leap in the usage model
-The same connector handles Level 2 and 3, plus an adapter for Level 1
-Already deployed along some highways for travelers
-Designed for public installation: weatherized and rugged (one-piece structure)
-Some locations are shaded by solar panels, reducing demand spikes
-Smaller than competing J1772 CCS plug, much smaller than CHAdeMO
-Two ports, at either side of car
-Uh, free charging, claimed to be forever?  Kinda appealing

-L3 is brutally more expensive than 5-15: cannot be in homes, most businesses
-New connector adds issues that existing standards bypass completely
-Proprietary to Tesla; no common infrastructure shared with other EVs
-Highway deployments may be congested, especially as Model S sales increase
-Some quality issues (sticking plugs) seen in early units
-Free charging may or may not turn out to be a long-term business plan
-Some locations aren’t shaded by solar panels, causing demand spikes

-Bad choice of name- gassers already had superchargers
-No separate charger in vehicle, but EVs need a low/med charger anyway
-Adapters to J1772, J1772 CCS, and CHAdeMO are possible
-CHAdeMO units also seeing balky connections/disconnections
-Ports are at rear of vehicle, not front

Tesla Model S/Supercharger Ground

Like the other Level 3 charging standards, this is an enabling capability. In this case, the network rollout has also been managed (along with good vehicle range) in a manner to address the key complaint of EVs… so long as you buy one, expensive EV.


6 thoughts on “Receptacle Roundup IXb: Tesla S

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