sv650john
Posts: 27
Joined: Tue Apr 15, 2014 12:55 pm

Re: 2015 Chevy Spark EV specifications

Tue Aug 12, 2014 12:37 pm

nmikmik wrote:It probably depends on how occasional is your LA trip. Couple of times a year, I'd take the Surfliner and figure out from there, couple of times a month - the 2014 or 2015 is not gonna save you I am afraid. If this is one and only car you have in your household, the long trips would become too much of the range anxiety especially if you are planing on keeping with the fast lane traffic... You could quick charge in Irvine, but it still takes time and availability of the charger is not guaranteed :(
I make the trip a couple times a month and I've considered the Surfliner. Only problem with that is there's no connections on the LA side, and my destination is actually in the Inland Empire nowhere close to any decent public transport. The trip takes about 6 hrs total according to google maps.

Just thinking out loud here - but if I could drive to the train station in SD, take the Surfliner to Anaheim and IF there was a Zipcar (or similar) type of setup at Anaheim station where I could pick up a Spark EV for the day that would pretty much solve the range / connection problem. When I'm done with it I'll just park it back at the train station, plug it in and take the train home.

Imagine this multiplying to train stations, airports, ship terminals (navy base in SD where 5000 guys get off an aircraft carrier and have no way to get around?).
Imagine if GM funded a startup company to do this - and then leased them hundreds of Spark EV's for the operation, thus accruing the CARB ZEV credits they so desperately need. They wouldn't even need to make money on renting the cars out, they'd break even immediately by not having to buy CARB credits from Tesla et al.

Are you listening GM?

nj1266
Posts: 23
Joined: Sun Aug 10, 2014 11:49 am

Re: 2015 Chevy Spark EV specifications

Tue Aug 12, 2014 2:27 pm

So chevy reduced the torque and upped the numerical gear ratio on the car for 2015. Wouldn't that end up giving the same or similar acceleration numbers to the 2014? Is there a way to determine mathematical acceleration numbers out of the weight, gear ratio, and torque for each model year?

Sparkler
Posts: 116
Joined: Wed Aug 14, 2013 9:33 am
Location: SJ, CA

Re: 2015 Chevy Spark EV specifications

Wed Aug 13, 2014 11:22 am

nj1266 wrote:So chevy reduced the torque and upped the numerical gear ratio on the car for 2015. Wouldn't that end up giving the same or similar acceleration numbers to the 2014? Is there a way to determine mathematical acceleration numbers out of the weight, gear ratio, and torque for each model year?
The torque at the axle works out to almost the same, about 2.5 Pound-Feet less on the 2015. Couple that with 86 Lb. less battery weight...
2014 1LT Electric Blue with Fast Charging
Replaced 4-14-17 with Arctic Blue Bolt EV BoltaDrome
https://www.voltstats.net/BoltEV/Stats/Details/9509

Nashco
Posts: 537
Joined: Wed May 29, 2013 12:00 am
Location: Portland, OR

Re: 2015 Chevy Spark EV specifications

Wed Aug 13, 2014 3:28 pm

So what happens if you use the 400 ft lb torque output of the motor with the 3.8 planetary ratio? :twisted:

Bryce

nozferatu
Posts: 575
Joined: Sat Feb 01, 2014 4:47 pm

Re: 2015 Chevy Spark EV specifications

Thu Aug 14, 2014 1:59 pm

Nashco wrote:So what happens if you use the 400 ft lb torque output of the motor with the 3.8 planetary ratio? :twisted:

Bryce
Insanity!

That would be so fun.

I would like to see better acceleration after 60 though. Can't wait to see a gearbox that can actually switch the torque curve for the motor somehow...it'll happen sooner or later.

kevin
Posts: 125
Joined: Sat Jul 27, 2013 9:52 am
Location: Los Gatos

Re: 2015 Chevy Spark EV specifications

Thu Aug 14, 2014 2:27 pm

nozferatu wrote:
Nashco wrote:So what happens if you use the 400 ft lb torque output of the motor with the 3.8 planetary ratio? :twisted:

Bryce
Insanity!

That would be so fun.

I would like to see better acceleration after 60 though. Can't wait to see a gearbox that can actually switch the torque curve for the motor somehow...it'll happen sooner or later.
Above 40mph it's probably not the motor that is limiting things but the output of the battery. The motor is operating in constant power mode at that point.

kevin

nozferatu
Posts: 575
Joined: Sat Feb 01, 2014 4:47 pm

Re: 2015 Chevy Spark EV specifications

Thu Aug 14, 2014 4:50 pm

kevin wrote:
nozferatu wrote:
Nashco wrote:So what happens if you use the 400 ft lb torque output of the motor with the 3.8 planetary ratio? :twisted:

Bryce
Insanity!

That would be so fun.

I would like to see better acceleration after 60 though. Can't wait to see a gearbox that can actually switch the torque curve for the motor somehow...it'll happen sooner or later.
Above 40mph it's probably not the motor that is limiting things but the output of the battery. The motor is operating in constant power mode at that point.

kevin
constant power mode? What do you mean?

kevin
Posts: 125
Joined: Sat Jul 27, 2013 9:52 am
Location: Los Gatos

Re: 2015 Chevy Spark EV specifications

Fri Aug 15, 2014 3:25 pm

nozferatu wrote: ...
constant power mode? What do you mean?
It is common for electric motor systems such as on the Spark EV to have multiple limitations to the torque that can be delivered at any one moment. Typically at low speeds the current allowed through the motor windings or the inverter is the limit. Since the torque is proportional to motor current this limit sets the maximum amount of torque that is available. The actual power output will be proportional to RPM as speed increases, at about 40mph this power will hit the second limit which is the power available from the battery. From that point upwards the system will be in constant power mode with the current (and hence torque) dropping as speed increases.

In spite of the various arguments that torque is what is required to accelerate the real limit is the ability to transform the energy from the battery into kinetic energy in the car. The gearing that works best for that will be the ratio that keeps motor in the power limited regime the longest - the 3.87 ratio is probably better for acceleration although for some reason GM reduced the peak torque so the thrust on the vehicle is virtually equal.

The presentation “2014 Chevrolet Spark EV Propulsion System by Steven Tarnowsky” has a lot of useful information about this - I can't found a link for it currently but it is available.

kevin

Nashco
Posts: 537
Joined: Wed May 29, 2013 12:00 am
Location: Portland, OR

Re: 2015 Chevy Spark EV specifications

Fri Aug 15, 2014 3:34 pm

kevin wrote: The presentation “2014 Chevrolet Spark EV Propulsion System by Steven Tarnowsky” has a lot of useful information about this - I can't found a link for it currently but it is available.

kevin
It's on page 2 of this thread! ;)

This is interesting as well:

http://www.mychevysparkev.com/forum/vie ... 2&start=10

Image

Bryce

nozferatu
Posts: 575
Joined: Sat Feb 01, 2014 4:47 pm

Re: 2015 Chevy Spark EV specifications

Wed Sep 03, 2014 10:08 pm

So has anyone driven the new Spark EV? Any quicker?

Had an interesting encounter tonight myself...this car puts a smile on my face everytime I smoke a car 3 times the price or more.

Sadly, the off line performance is lacking however.

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