It's a 90A Circuit Breaker. However, the maximum current for the vehicle is
70A, as set by the duty cycle of the Pilot waveform.
At 240v that is 16.8 kw*4 to do a full charge, or 67.2 kw total. At the
national average of $.12 per kw that is about $8 ($.04/mile) for a full
charge to drive those 200 or so miles. This is about 1/3 the cost to drive
an average gas vehicle at 20 MPG and $2.60 per gallon.
And again, this is an example of comparing apples to oranges. These
electric vehicles are relatively small cars. And they should be
compared to similar size fuel efficient cars, not the average gas
vehicle. There are lots of car choices getting 30 city, 45 highway
or better. The Toyota Prius gets 51 city 48 highway giving a fuel
cost of about $12. Here in the northeast with electric at 17c kwh,
and using your above math, the fuel cost on the Prius vs the electric
is a wash here.
But I bet the Prius is a far more drivable vehicle, capable of higher
sustained highway speeds, etc. and doesn't have the obvious drawbacks
for the user that the electric car has.
Interesting choice for comparison since the Prius is a hybrid (partly
electric) car. It is likely to include an option to charge the
(relatively small) battery off the grid in the not-too-distant future.
From what little I have seen, the Tesla is a sports car - high
acceleration, probably better high speed behavior.
This talk about loads gets one thinking. Since 99% of homes and 100%
of new ones here are electrically heated. And as it happens our island
wide electrical sytem for a population of some half million persons is
not connected to the North American grid.
Any new domestic installations for last 30/40 years or more have
required 200 amp services.
Distribution transformer loadings (with anywhere from 3 to say 8 homes
per transformer in suburban areas) must be installed on some sort of
diversity. My heating won't be on simultaneously with all my
neighbours, eh? I won't be cooking dinner, or taking a shower at
exactly the same time etc. And in fact I will never be using all that
200 amps anyway? But if I were to plug in my 90 amp car
recharger ...................... ! Hmmm!
Well I'm getting out my popcorn to sit back and watch the show in California
with this. They [California] had a fit with everyone buying those new TV's
which use a bit more energy. (Overloading the electric grid.) In California
no one wants any new major electric transmission lines built in their
If quite a few people buy these cars in California, it will be interesting
to see what they do when it places a strain on their electric grid.
Or for that matter if there was a concentration of these new cars in one
neighborhood anywhere. Say 3 homes all on the same electric company
transformer. Then all 3 homes get electric vehicles, and they all recharge
them at 6:00 pm when they get home on a hot summer day, and also have their
AC and everything else going full blast???
Neighborhood Nuclear Power...
OK if you have off-peak rates; which make great sense by the way. By
spreading the load.
Some places in the UK for example they have (or had) heat storage
heaters that used electrcity at night at a cheaper rate.
The cheap rate switched off early in the morning as people got up,
made breakfast, used electric trains and street cars to get to work,
factories started up etc.
You have a choice. In his hypothetical case of several homes sharing
a transformer, you can either design for worst case or ignore it. The
latter could very well result in the transformer overloading and the
homes being without power. And his point is a very valid one. The
existing transformer loads were calculated based on some assumptions
of what loads would be in the future and a worst case scenario had to
be calculated. I would not be surprised that suddenly having homes
where new 70A loads for 4 hours appear could exceed the system design,
with his transformer loading being a good example.
As for using a longer term lower current, there are two big problems
1 - The longer it takes to recharge the car, the less attractive these
cars become and they become totally excluded from many applications.
That's especially true when you compare their operating costs with
similar size ICE cars available today, eg hybrids, that have no
2 - In today's instant gratification world, I doubt many people are
going to want to charge it at less than the maximum. You need to run
a new circuit to charge them anyway, so why would you not make it
capable of charging at the max? And once you have that 90A circuit,
you know people are going to use it. You could discourage this by
offpeak pricing. But that gets back to what I said a long time ago,
which is that you need to talk about a COMPLETE solution, from energy
generation to the point of usage, not just an electric car. Yet, the
miracle, clean, green electric car is all the media cares to talk
As with any other big addition of power using equipment, you let the power Cc.
know what you are doing (By getting a permit?) The transformer problem is then
their responsibility. At least that was what I was told when I added a hot tub
You're the first residential user that I ever heard of that notified
the power company because they were installing a hot tub. In the
rest of the residential world, no one is keeping track of what loads
get added. You put in a 200amp service and that's the end of the
story. If you need more capacity, THEN you call the electric company
and upgrade to 300amps.
It puts me in awe of the power of gasoline when you consider that the
equivalent POWER flow through an ordinary filling station hose at the
gas station when you fill up your car is measured in MEGAWATTS!!!
Right now it's not an even comparison. But I think you'll all agree
we're closer to the end of reasonably priced gas than we are from the
beginning. No matter how much you think is left it's definitely a
finite resource. On the other hand there are all sorts of potential
new sources of electricity. Many that are of limited practicality
right now have potential to become more practical either because of
technology improvements or just volume increase. Most are "green" and
do not add to the carbon dioxide load. Like it or not the days of
gasoline powered transportation are numbered.
The SUN is a finite resource!
"HOUSTON - ExxonMobil Corp. added two billion barrels of oil equivalent to
its proved oil and gas reserves in 2009, or 133 per cent of its production
for that year, the largest U.S. oil company said Tuesday..."
That is, Exxon FOUND a third more oil than they recovered.
I agree. If you had asked the average New Yorker in 1910 what would
transportation be like in a hundred years, with a population increase of
five-fold, he'd have probably wondered a) Where would we get enough horses,
and b) What would we do with all the horse shit.
I'm personally rooting for teleportation.
You get permit for electrical work from the local municipality. They
usually charge a fee and send out an inspector to make sure the work
is done according to code. What does any of that have to do with
your claim that the power company routinely gets notified when you add
a large residential load like a hot tub? Please provide a cite for
that. I'd also welcome hearing from anyone else here that notified
the power company that they were adding a hot tub or similar load.
You notify the power company when you need an upgrade in the service
capacity to the house.
Just as I said. The power utility told me they need to know about major
additions. They said if I added something large, and they did not know, I could
be responsible for damage to the transformer. I assumed that they generally got
the info from the permit process, since a permit is required for any electrical
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