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Charging Choices

Charging Choices

I have seen a number of people asking about the various charging configurations. It took me a while to sort it out. The table below summarizes my understanding. Corrections and comments welcome.

  • Household Plug (US) using included Universal Mobile Connector
    Typical Circuit: 120v/20 amp
    Range recovery rate: 6 miles / hour
  • Dryer Plug (US) using included Universal Mobile Connector
    Typical Circuit: 240/30-50 amp
    Range recovery rate: 20-30 miles / hour
  • J1772 using included Universal Mobile Connector
    Typical Circuit: 240/30 amp
    This is the 'standard' EV plug found en-route. Higher amperages available over time.
    Range recovery rate: 24 miles / hour
  • High Power Connector (HPC)
    Typical Circuit: 240/50 amp
    Must purchase and install HPC ($1,200 + installation)
    Range recovery rate: 30 miles / hour

    Typical Circuit: 240/100 amp
    Must purchase and install High Power Wall Connector ($1,200 + installation). Car must be equipped with a second onboard charger ($1,500).
    Range recovery rate: 60 miles / hour

  • Super Charger
    Typical Circuit: NA
    Will be available en-route over time. Locations TBD. Only ~75% of battery range can be charged this quickly.
    Range recovery rate: 300 miles / hour
stevenmaifert | 23 Janvier 2012

That looks about right. The HPC/Twin Charger option would only be necessary for those who will drive the battery to near depletion every day and need the faster overnight charging. When you figure the cost of installing the HPC, some locales require permitting in addition to the cost of the electrical work.

brianman | 23 Janvier 2012

It takes 50 hours to refill an 85kWh from 110V/20A? Ouch.

petero | 23 Janvier 2012

The more I read and listen, it occurred to me that there is nothing wrong with the 40-60-85Kwh batteries' range(s). Many ICE cars need to refuel every 2-300 miles.

It seems (to me) to make more sense to develop ultra fast (and safe) charging methods rather than bigger more powerful batteries. Being able to “tank up in ” 30 minutes or less could be a real game changer.

So what do you think?

stephen.kamichik | 23 Janvier 2012

I agree. Hopefully there will be charging stations every 100 miles along North American major highways.

David M. | 23 Janvier 2012

You don't need to purchase and install an HPC for $1,200 to get 30 mi per hour recovery rate. Just have an electrician install a 240V/50A circuit in your garage with a receptacle. This will cost about $200 to $350 if its close to your electrical panel box.

Then just plug in the cord that comes free with your Model S.
The 300mi battery will be charged in less than 10 hrs.
The 160mi battery will be charged in less than 5 hrs.
The 230mi battery will be charged in less than 7.5 hrs.

Mycroft | 23 Janvier 2012

That was his second option David, the "Dryer Plug".

Yes, while you *can* use the UMC with the 50A receptacle, if the main panel is limited to a spare 50A, then an argument can be made to have an HPC installed, connected to that 50A breaker. You still have the convenience of the nicer connector while not paying much more than you would for a second UMC.

David M. | 23 Janvier 2012

@Mycroft - thanks, missed it.
With a 300mi battery, I figure I will almost never take the UMC out of the garage. Therefore, I'm hanging it on the wall and leaving it there (not likely to be stolen in my garage).

With a J1772 adapter, I can still use public charging stations on the rare occasion.

Larry Chanin | 23 Janvier 2012

@petero
It seems (to me) to make more sense to develop ultra fast (and safe) charging methods rather than bigger more powerful batteries. Being able to “tank up in ” 30 minutes or less could be a real game changer.

So what do you think?

To accelerate EV adoption with current battery technology we will need multiple approaches. Bigger batteries, fast charging infrastructure, and even battery swapping approaches.

The problem with DC fast charging is that the smaller the battery and the more depleted the battery is, the more damage the fast charge inflicts on the battery. So if by "ultra" fast charging you are referring to something faster than a Tesla Supercharger, then with Tesla's current battery technology that would probably require a bigger battery pack to minimize damage.

Larry

Sudre_ | 23 Janvier 2012

I am thinking the other direction on the battery. I would prefer not to stop and charge every 100 miles or even every 300 miles. If a battery can take me 1000 miles I would only need to charge at home. Who cares if it takes 24 hours to charge or even a week or ten. I could recharge the car on 120 volt/20 amps. The car does not need a 100% charge every time I take it out.

Lets look at an extreme case in my opinion.

Fred picks his car up at Tesla Chicago with an 80% charge or;
800 miles.
He drives it home to St. Louis which is about 320 miles away at 70 MPH. His driving style leaves him with 350 miles left on the battery.
He plugs into the 240 volt 30 amp plug at 8pm Sunday night and doesn't return until work the next morning, 10 hours. He gains 200 miles on the charge putting him at;
550 miles.

Work does not have a plug or charger at work and Fred's boss told him he's not putting one in, "electric cars are stupid!"
Fred's bad driving habits takes his 50 mile one way commute and bleeds off 120 miles from the battery. He is now at;
430 miles.

Fred takes his wife out that night and the car gets home and plugged in around 9pm down another 50 miles at 280 miles. By work time the next morning he has gained 180 miles of charge or;
460 miles. Another 120 miles used for work and back and he's back in the garage at;
340 miles.
This time they stay in and the car charges 'til work time the next morning. He's at;
580 miles.

If you follow this logic for a week, at most two weeks, you can see that the battery will get to the 800 miles 20% charge point without needing a charger outside the house. Fred has plenty of charge to make another long weekend round trip. This time he can put it in range mode and get the full 1000 miles.

Larry Chanin | 23 Janvier 2012

I interpreted petero's question to be in the context of current battery technology. Sure we would all love a car with a 1000 mile range, but today that is not feasible from a cost or weight perspective.

Larry

Sudre_ | 23 Janvier 2012

@petero
"It seems (to me) to make more sense to develop ultra fast (and safe) charging methods rather than bigger more powerful batteries"

That sounds more to me about what to research for the future than what we have now.

jbunn | 23 Janvier 2012

I suspect most of us are over concerned about getting the battery charged fast enough. I like to think about the amount of time my car is turned off. Most days it's 13 hours parked and a 70 mph RT commute, average speed about 35 mph. 13 hours off a standard plug fills me right back up. And I don't go to work every day, so sometimes it sits longer. I just need to get in the habit of plugging it in when I'm not driving it.

I do electrical work, but I might not even put in a 240, even though it's 3 feet from the fuse box. Just really think I'll be fine. I don't need to charge in 3 hours, and sit for the rest of the night. My two cents, anyway...

Timo | 24 Janvier 2012

Thing with batteries is that with current major steps in development coming (slowly) in consumer batteries it reduces the weight and volume of the same capacity battery which directly lowers the cost in linear way (manufacturing same size, but double capacity costs same as older one), but also that when BEV really gets to break thru in general public also battery manufacturing volumes increase and that lowers the cost further.

So there is two variables lowering cost while only one to increase capacity / weight.

I believe 1000 mile battery will cost less than 300 mile battery costs now in relatively near future (like, say, ten to fifteen years?) and be about same size.

1000 mile battery is rather large. I could settle with 600 mile one if there are chargers that can recharge that in couple of hours at every 300 mile or so and in every city.

Sudre_ | 24 Janvier 2012

I'm with you Timo. In reality I could get by with a 500 mile battery. The difference is everyone seems to thinking charging will be free or cheap. Once the electric car gets established, in my opinion, you are not going to get cheap charging. Everyplace you plug in at public or corperate spot is going to have a credit card swipe and it's going to cost as much or more than gas to fill up simply because they can..... once the demand exists. 10-15 years. I hope I am wrong but I like being a happy pessimist.

EdG | 24 Janvier 2012

Once the range is increased beyond what sane people drive in an entire day, the need for roadside charging dissipates. Such stations would then only be used for the forgetful or those who are switching drivers and traveling 24 hours per day. Charging at home, RV campsites and hotels becomes the norm, and roadside stops would be for human purposes (eating, etc.) only.

brianman | 24 Janvier 2012

"Everyplace you plug in at public or corperate spot is going to have a credit card swipe and it's going to cost as much or more than gas to fill up simply because they can"
"Once the range is increased beyond what sane people drive in an entire day, the need for roadside charging dissipates."

It's been mentioned before but probably bears repeating.

Initially, yes, some of the charging locations will consider themselves "premium" and try to bill you accordingly. They will also be trying to recoup installation costs.

As it becomes more common, the number of locations increases and the sense of premium decreases. Over the long term it becomes one of the many "value adds" that the location offers.

Think wireless hotspot in coffee shops. Do you pay for internet at Starbucks? Directly - no. Indirectly - yes, but so do all the people *not* using the wireless.

Larry Chanin | 24 Janvier 2012

@EdG

Once the range is increased beyond what sane people drive in an entire day, the need for roadside charging dissipates. Such stations would then only be used for the forgetful or those who are switching drivers and traveling 24 hours per day.

This article supports your point.

Will Tesla Crack the Range Anxiety Problem?

After visiting Tesla headquarters and meeting with the management there, J.P. Morgan [JPM 37.38 -0.28 (-0.74%) ] is telling clients it can see Tesla developing a 400 mile range powertrain in the next 3-4 years.

Analyst Himanshu Patel wrote, “…a 400-450-mile range capable vehicle may be the tipping point, in our view, where the range is so clearly overkill (for daily use) that Tesla’s addressable market is then truly expanded to fully encompass the affluent yet single-car household.” In other words, a Tesla model that gets 400 or more miles on one charge could be much more than a niche electric vehicle.

Larry

Klaus | 24 Janvier 2012

Sounds like the old Betamax vs VHS or PC vs Mac senario. One industry will focus on increasing battery capacity and decreasing size and cost while the other will seek to install super fast chargers around the country. Separate industries looking to capitalize on the EV revolution. We may end up with both as with the Mac and PC or only one (not necessarily the best as with VHS). It's all about making a buck.

Klaus | 24 Janvier 2012

And keep in mind that the current ICE producers have had the technology and opportunity to give us better mpg and or larger fuel tanks. Yet these cars, amazingly, still only travel about 300 miles per tank requiring frequent stops on lengthy trips.

EdG | 24 Janvier 2012

I'd guess cars are engineered to go about that distance. Why carry around extra fuel when there are gas stations everywhere? Buyers don't want to see too high a price tag when they fill up, gasoline is dangerous and heavy, and there are better things to do with the volume. And it only takes 5 minutes to fill a tank.

Klaus | 24 Janvier 2012

Chicken or egg theory, which came first larger gas tanks or more gas stations? I'm guessing the reason for so many stations was due to the limited range of the first cars. That followed with less demand for fuel economy and thereafter smaller tanks and better economy. Remember the old gas guzzlers of thew 50's? My dad had an Olds 88 back in the 60's with a 19 gallon tank. I think it got about 12-14 mpg. I'm guessing the real reason for smaller tanks with better economy is to keep all those stations in business. As it is, this places already have to suppliment there income buy selling "mystery meat" dogs and 64 oz drinks (which by the way won't fit in the S' cup holder).

EdG | 24 Janvier 2012

As we can see, it's always, eventually, all about the cup holders. :)

Klaus | 24 Janvier 2012

I'm having mine removed. First person that attempts to bring a drink into my new (I can smell the leather already) car gets punched in the face. ;)

Klaus | 24 Janvier 2012

Back on topic, I'm haveing a 240v line with dual 14-50 outlets installed just in case Tesla produces an electric pickup.

Larry Chanin | 24 Janvier 2012

Hi Klaus,

Depending on what you expect the amperage to be delivered to each car, that could be easier said than done, with two EVs charging off of the same 240v line.

Larry

Klaus | 24 Janvier 2012

Just need a 100 amp circuit.

Larry Chanin | 24 Janvier 2012

I'm not an electrician, but from what I've been reading the breaker has to be 120% greater than the expected current. So that means a 120 amp breaker if both outlets are drawing 50 amps.

Larry

Klaus | 24 Janvier 2012

Not necessary. Just like the roadster, you only use 80% of the rated amps (40 each). A MEMA 14-50 requires a 50 amp line. I'm sure the S can be programed to charge at a specific rate if necessary.

brianman | 24 Janvier 2012

@Larry - 125% / 80% depending on which way you want to do the math

Mycroft | 25 Janvier 2012

You're much better off running two separate 50A circuits than trying to connect two 50A receptacles to a single 100A circuit. There's probably a legal way to configure the latter, but it would be very tricky with the large wiring required for a 100A circuit and would require a sub-panel of some kind.

EdG | 25 Janvier 2012

I disagree.

If you're never going to charge using more than 50 amps at a time for two cars, then one 50 amp circuit would be enough - even if you have two plugs available on that circuit. (You might program the cars to charge at different times.)

If you're going to use both 50 amp circuits at the same time, you'll need 100 amps available, whether it's two 50 amp circuits or one 100 amp circuit makes no difference. You still have to have enough copper to get the amps there. The only difference would be that you might want to put separate circuit breakers on each of the two vehicles. I wouldn't; I'd rather let some future car draw more than 50 amps on schedule if it's capable of doing so.

stevenmaifert | 25 Janvier 2012

Mycroft is exactly right; particularly if you will have separate metering for charging the EV to take advantage of night time reduced rate charging if your utility company offers that (http://sdge.com/clean-energy/electric-vehicles/ev-rates).

cerjor | 25 Janvier 2012

Is the model S compatible with the Blink charging stations? There seems to be a lot of them in places such as Wallmart and Ikea.

stevenmaifert | 25 Janvier 2012

Is the model S compatible with the Blink charging stations? There seems to be a lot of them in places such as Wallmart and Ikea.

Yes, with the use of the J1772 public charging station adapter that will come with the Model S.