Unveiled at the Los Angeles Auto Show, the 2014 Chevrolet Spark EV uses a GM-designed, coaxial drive unit and electric motor that deliver 130 hp (110 kW) and 400 lb-ft (542 N-m) of torque. (Source: GM)
Once you get a car moving at a consistent speed, you don't need very much horsepower, especially if it has a low drag coefficient, and this looks like it probably does. Regenerative braking helps a lot with stop&go traffic. More fundamentally though, this sort of car you do the equivalent of going to the gas station every night, at home (takes 5-10 seconds to plug or unplug it). So, it doesn't need much total energy in the battery.
If we take the battery capacity, 20kWH, and divide that by 746 watts per horsepower we get a potential battery capacity of putting out only 26.8 horsepower for 1 hour. That is pitiful compared to a gasoline or diesel fueled engine. Then turn on an air conditioner and the range drops even further. I don't think GM will sell many of these turkeys in Southern Arizona.
With the Oldsmobile now defunct maybe GM should call its Spark the "Obamamobile."
The article says that the Spark supports a 20-minute 80% charging cycle. That doesn't imply that homes can support it.
I'd expect that 99.5% of the time you'd charge it overnight at home, but three or four times per year, you'd need that fast charging cycle, and it will be very desirable to have. Assuming that somebody buys, literally and figuratively, the premise of such a vehicle, then I bet such customers would be willing to pay for that charging cycle on the few rare occasions its needed.
I perceive this car to be optimized for normal day-to-day driving within the range of a typical metropolitan area and its suburbs. Anything else will require rare and somewhat-extreme measures, which is what I perceive this 20-minute charging cycle to be.
I can imagine this sort of vehicle being my family's primary vehicle, but where we also have a cheap, reliable, old Toyota Corolla, say. I drive the Spark frequently, my wife occasionally drives the Corolla while I'm out at work (she doesn't work outside the house), and we, two or three times per year, hop into to take long road trips. In other words, 80-90% of the driving would be in a Spark or Leaf, but we still have a ho-hum gasoline car for comparatively rare cases when we need to drive to different at the same time, or need to take long road trips. I expect that's the sort of use case GM, Nissan and others have in mind for this sort of vehicle.
JayBee: Thank you to readers such as yourself who said the vehicle can't be charged in 20 minutes from a home outlet. You are absolutely correct. Our earlier story about the SAE fast-charge standard explained that SAE fast-charging is for public charging stations. Click the link to the earlier story to learn more. In the meantime, we are adding a sentence in this story to explain that the battery can be charged from a 240V home outlet in seven hours. My apologies for the omission and thanks again for your comments.
'Normal' charge for a home charger would almost certainly be at 220V. I have no actual info on their plan, but I'd bet that the 20 minute variety is done on 480V 3 phase (277V from each 'hot' to ground), which would drop the current demand to under 60 amps per leg. 480 V 3 phase is available in most large buildings.
You are absolutely correct that fast charging would not be from a residential 110 volt outlet. But 220 volts gets the current down to 218 amps! Most residences are serviced from 440 volt lines which gets it down to 109 amps.
Even allowing 2 hours gets it down to only 36.3 amps on a 220 volt line. No residence has that kind of wiring either.
My point is that the article is misleading when it makes that claim. So, what else is misleading or just plain false?
Charging stations are fine but will have to charge (oh bad choice of words) for the electricity. In my state, 10kwH costs $1.90 at retail rates. What would the owner of a charging station have to charge to get a reasonable return on his investment?
Did I see a hint of Ayn Rand a the end of the article? Manufacturing because the government said so?
EV's will only sell when there range is comparable to fueled vehicles, recharge quickly, and priced equally (without subsidies). Not sure if the physics works out for the first two items as the definition of quickly recharging has to be the same as refueling. No one likes to stand around for 20 minutes to recharge. Though I suspect this would be a marketing boom to convience stores!
Your calculations sound right, but I doubt if that charging option will be available from a 110V outlet. In a home-usage scenario, you'd probably charge it up over a couple hours or so, from a 220V outlet. That's fine for me though, since I drive more than 50 miles per day ... maybe once every couple weeks or so.
It would be very cool to see charging stations, such as at large truck stops on Interstates and other large freeways. The Spark may be able to go from Austin to Houston or back with only one 20min stop. I'm guessing that it's more likely to have an 80-90 mile real-world range (air conditioner or heater on), which would require two stops on the way.
One 20-minute break wouldn't be much of a problem (if not desirable) but two might be a little annoying. Then again, I only take that sort of trip two or three times a year, so I might just rent a car instead.
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