Charging a Tesla roadster from household outlet could take 30 hours!
The gang from Tesla left their Silicon Valley home base to pay a visit to the vicinity of the Big Apple this week. Part of the purpose of the trip was to spend some time with some of the people in the area who've plunked down cash toward a Roadster but haven't yet taken delivery (which would be almost everyone on the customer list at this point). One interesting note in the article from Greenwich Time is the length of time required to charge up the Roadster's battery. They note that charging the battery from a normal household outlet could take up to 30 hours. The Roadster's battery has a capacity of 53kWh. Tesla quotes a charge time of 3-3.5, but that is based on charging from a 220V 80A circuit. If, on the other hand, you plug the car into a typical outlet in your living room, you would only have 15A flowing at 110V. That's 53,000W / (110V * 15) = 32.12 hours. So if you plan to get yourself a plug-in electric car with any kind of serious range, be prepared to have an electrician install a high current outlet to charge it. At the very least you'll want a 220V/40A circuit for overnight charging in 6-7 hours.
[Source: Greenwich Time]
Reader Comments (Page 1 of 2)
axiom 9:00PM (7/06/2008)
Most homes have "high current outlets", that is if you have an electric oven or washer/dryer, which most do. If you can afford the roadster, you can probably afford an outlet where ever you want one.
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ooglek 9:38AM (7/07/2008)
I don't get why they allow you to aggregate 110v sources. If you can find two or three 110v sources on different circuits, you could get up to 45A. Sure, not 80A, but that's 10 hours instead of 30. And yeah, you gotta carry a bunch of extra extension cords, and maybe some smart electrician can build some simple tool to determine if the outlet is on the same circuit as one you are already using, but it's doable. It's a hack, but who doesn't love a hack?
ooglek 9:45AM (7/07/2008)
I meant "I don't get why they DON'T allow you to..." oops.
BlackbirdHighway 8:59PM (7/06/2008)
Slow news day, but then it's Sunday, what do you expect.
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Andrew 9:07PM (7/06/2008)
I was there and that was my question!!
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nist7 9:11PM (7/06/2008)
Doesn't virtually all homes have a high current outlet for washer/dryer/electric oven?
But I doubt it'll deliver 80amps, so 40amp doesn't seem all that urneasonable for a conventional home to have.
Where are the electricians/engineers?
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ph39 9:54PM (7/06/2008)
Not an electrician - but most homes have 240v 40amp or 50 amp lines (AC and Electric dryers). However, very few homes will have room for an additional 240v/40amp line. Most homes have 200 or 250 amp service and are very close to their limit with their current wiring. Probably will require most people to have a new line run from the electric company / a new circuit box, and new wiring to their garages. Probably a couple thousand dollars.
GoodCheer 9:18PM (7/06/2008)
The math is pretty simple.
Another way to think about it is since you'll be using about 250 Wh/mile, if you use a (110V x 20A) 2.2 kW plug, you'll be charging at about 9 miles range per hour.
For what its worth, my boss had a 240V x 50A plug put in a waterproof box on the side of his house (where it was accessible from his driveway), for ~$750 including city inspection and everything. As axiom says, the cost of the plug is really pretty trivial next to that of the vehicle.
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Graham 10:51PM (7/06/2008)
Why is this news now? You have reported this fact on this very web site well over a year ago.
http://www.autobloggreen.com/2007/02/01/first-hand-impressions-after-riding-in-the-tesla-roadster-plus-a/
All Tesla Roadsters come with the high capacity charger to be installed in the owners garage. It is part of the purchase price. No Tesla owner will use the "typical outlet in your living room" unless they were topping off while on the road. That isn't to say there won't be an occasion to charge remotely, but that should be the rare exception and not the rule.
-g
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Doug 1:44AM (7/07/2008)
"Why is this news now?"
My sentiments exactly. TTAC had a similar post based on the exact same story, except Farago harped on the fact it could take 8 hours to charge.
http://www.thetruthaboutcars.com/tesla-death-watch-9-8-hour-recharge-time-in-theory/
This is not news and doesn't deserve a sensationalistic headline. For TTAC, this is par for the course, but I expect better from ABG.
BlackbirdHighway 10:51PM (7/06/2008)
Around where I live, 400 amp service has been the standard power company service since the 70's. Still, even though the feed wires are 400 amps, most houses have a 200 amp panel and main breaker.
You are allowed in the code to have the total of the load circuits be well in excess of the main breaker. It just means that if you run every possible appliance at the same time, you may blow the main breaker and have to reset it. Usually, it's next to impossible to do that:
* You would have to run your electric heat and air conditioner full blast at the same time
* and put your electric stove in self cleaning mode
* and run the washer and electric clothes dryer
* and somehow get a circuit with half a dozen 60 watt bulbs to draw 1800 watts
* and plug in blow dryers into every outlet circuit
* and recharge your Tesla at the same time
The Tesla has a timer, so most of the time you'll be charging late at night, when other power draws are at minimum. Lots of power companies also give you a break on the price at nighttime.
If you're charging during the day, you may want to avoid running the stove, dryer, and AC all at the same time, or maybe upgrade your electric panel.
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meme 11:06PM (7/06/2008)
Those who write articles about charge times should do them correctly.
#1) The US is a nominal 120V, not 110V. Lots of people call it 110V. They're wrong. In fact, 110V isn't even supposed to be allowed; the valid range is 114V to 126V. Now, that doesn't mean that if you check the voltage of an outlet, you'll get 120V. Odds are, you won't. 117V seems to be pretty common, so I'll use that.
#2) This completely ignored charging losses. Which, on the Roadster, are pretty significant -- it has under 75% efficiency in its normal charging mode. You'll probably get better with slower speed charging (less cooling requirements), but you most definitely cannot discount it. Even the best li-ion EVs tend to get only ~93% efficiency in the charger and ~99% efficiency in the battery pack.
#3) This completely ignored the slowdown at the end of most charge cycles. Of course, slow charging suffers this notably less. This might be able to be discounted in this case.
#4) If it's a kitchen outlet, it's 20A. If it's a dryer outlet (NEMA 10-30 or NEMA 14-30), it's 30A split phase, so ~240V. If it's a range (NEMA 10-50 or NEMA 14-50) or high power RV outlet (NEMA 14-50), it's split-phase 50A.
Going with a more reasonable calculation for a non-kitchen NEMA 5-15 ("Type B"), you have 53,000 / (117 * 15 * 0.85) = ~35.5 hours. I think 85% efficiency is being too generous to Tesla, though. Their charging is pretty wasteful.
Due to the battery chemistry, Tesla will never be able to charge in less than one or two hours, depending on how paranoid they want to get. Other, more stable chemistries, however, will be able to. There's already a network of 60kW chargers across Oahu (53kW, 96% efficiency since this is DC but high amperage, = 55 minutes plus slowdown at the end if you do a 100% charge), and the same company that made them (Aerovironment) has chargers as big as 250kW (53kW pack, 94% efficiency, = 14 minutes plus slowdown at the end).
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a.brien 11:11PM (7/06/2008)
That's a huge battery to charge... And where do you charge it if your not at home? Better off with cheap hydrogen home made at 40 cents/gallon. Or some bio-diesel homemade with a small algae bio-reactor.
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Chris M 12:48AM (7/07/2008)
Well, you charge it at an available electrical outlet, they are everywhere. RV parks have plenty of 220 volt 50 amp outlets available.
But where will you refill your H2 car when away from home? Darn few locations, mostly run by oil companies. It is a bit disingenuous to castigate EVs for "away from home charging" (which isn't that big of a problem), yet suggest the alternative is home made H2!, Charging can be done at home too, using 1/3 as much electricity of even the best electrolysis unit available. .
I'm a bit confused by your reference to "cheap hydrogen home made at 40 cents/gallon". H2 is a gas, normally measured in kilograms, as the volume changes drastically when compressed. So at what pressure is that gallon of homebrew H2? At standard atmospheric pressure, a gallon of H2 is the energy equivalent of just a drop of gasoline. A rough calculation estmates that your "40 cent/gallon" homebrew would be the "per gallon of gas" equivalent cost of of $1,333.33 That's absurdly expensive, even by H2 hype standards. Maybe you've just got a horribly inefficient electrolyzer!
Phil L. 11:15PM (7/06/2008)
This is why, as part of a home remodeling project, I upgraded my home's electrical service - and left a virtually unused 240V 100A panel in my garage.
Sadly, no money left over for a Tesla...
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jpm100 11:26PM (7/06/2008)
The question is can you charge it and run your Dryer at the same time?
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Chris M 1:45AM (7/07/2008)
30 amp dryer plus 70 amp charger = 100 amp, about half of the common 200 amp home service. Unlikely to be a problem, unless you really get carried away in running things.
Of course, you could avoid any problems by using a clothes line.
Luke 11:42PM (7/06/2008)
Just have your servants bring you your other Telsa when you're getting low. Then they can drive it back to the garage to charge while you're using the other one. Nyuck, Nyuck.
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Steve 12:32AM (7/07/2008)
What? Nobody offered the quote, "220... 221... Whatever it takes" yet?
I bought a heavy duty 220w heater for my detached garage a couple of years ago. Swapping out the 110w breaker for a 220w breaker was a piece of cake, as was laying the heavier guage wiring and mounting the outlet. A requirement for this type of outlet really doesn't pose much of an obstacle.
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EV-1 5:11AM (7/07/2008)
*deep sigh*
Like #8 (Graham) and #9 (Doug) :
Why is this news Now ?
Well, llike #1 (BlackbirdHighway) : it's slow news sunday - what do you expect ?
Bright idea ! Turn on the tap and let some of that good ol' TESLA-ISM trickle through, of course !
I can't even start to think what they're paying the columnists for all this exposure.
Them Tesla lobbyists shure know the trade !
- Really, it's as awesome as it is revolting.
Man, it wouldn't be surprising if you end up rejecting that icon out of sheer fatigue !
Suggestion to those suffering severe Tesla-ism to seek proffesional help.
This is getting weird
:S
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