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CANbus 0-60 time

Posted: Thu Aug 18, 2011 2:53 pm
by sparky
Here's my first try at getting a 0-60 MPH time from the CANbus data.
I ran about eight tests. The runs from this section of road seem to be the most consistent.
Plotted here are two runs from the same section of road; traction control on/off.
I was thinking the TC off data would be a bit quicker but not in these first tests.
Really no difference that I can see. I think the little 'blip' at the early part of the plot is wheel skip from a road partition.
I may do a few more just to convince myself about the times. As always YMMV.

Just for amusement, I also have power curves from V * I data (2nd plot). Looks like I pulled almost 90kW peak, but it takes until almost 3000 RPMs to get to max power output. I am assuming this is data at the battery pack (pre conversion loss) but not sure. Data seems reasonable although my interpretation of CANbus Volts and Amps is still speculative. The plot shows max re-gen power of about 40 kW as I slowed down.


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Speed vs power.
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Re: CANbus 0-60 time

Posted: Thu Aug 18, 2011 3:27 pm
by johnr
Thanks for the informative graphs. Quite interesting.

Why does the regen appear so erratic?

Re: CANbus 0-60 time

Posted: Thu Aug 18, 2011 3:33 pm
by EricBayArea
I have read reviews where people estimate the 0-60mph time as being around 9 seconds and then a reviewer that timed himself a few times at around 7 seconds. Not having my Leaf yet, I have test driven twice and both time I swear the car felt like it could pull of 60mph in the 7-8 second time-frame. Honestly felt faster than 9 seconds.

Re: CANbus 0-60 time

Posted: Thu Aug 18, 2011 3:36 pm
by TomT
No, virtually every test I have seen in the various car magazines has pegged it in the high 9 second range... It just feels faster apparently...
EricBayArea wrote:I have read reviews where people estimate the 0-60mph time as being around 9 seconds and then a reviewer that timed himself a few times at around 7 seconds. Not having my Leaf yet, I have test driven twice and both time I swear the car felt like it could pull of 60mph in the 7-8 second time-frame. Honestly felt faster than 9 seconds.

Re: CANbus 0-60 time

Posted: Thu Aug 18, 2011 7:02 pm
by sparky
johnr wrote:Thanks for the informative graphs. Quite interesting.

Why does the regen appear so erratic?
Dunno, but not sure what you mean. When not flat-out accelerating as in the first few secs, both power and re-gen sides seem to have about the same amount of modulation.

Re: CANbus 0-60 time

Posted: Thu Aug 18, 2011 11:23 pm
by evnow
sparky wrote:Here's my first try at getting a 0-60 MPH time from the CANbus data.
How are you getting the speed - that is not in EV can, right ?

Re: CANbus 0-60 time

Posted: Thu Aug 18, 2011 11:36 pm
by nader
This is great data. I know a bunch of you guys are working on interpreting the data still but is three any plans to do ECU flashes to remap the throttle curve, increase regen, eliminate creep etc?

After 5,000 miles of driving I have realized that I want full regen on the throttle pedal. Tired of using the brakes to slow down. I also don't want creep anymore since I always put it in neutral at a stop light anyways. And it would fun to have the power ramp up quicker for those with stickier tires. If the juice could come on quicker at the bottom end you could easily shave a second off of the 0-60 times.

Re: CANbus 0-60 time

Posted: Fri Aug 19, 2011 12:35 am
by Herm
With a long and steady braking run you could work out the kwh/m number for the regen events.. then we would know efficient regen is in recovering energy.

We know regen is not 100% efficient but it would be nice to pin down the real number.

Re: CANbus 0-60 time

Posted: Fri Aug 19, 2011 7:05 am
by sparky
evnow wrote:How are you getting the speed - that is not in EV can, right ?
Yes, from EV-CAN. Derived from my guess at an RPM field, described in this numerically dense post/plot here.

Re: CANbus 0-60 time

Posted: Fri Aug 19, 2011 10:38 am
by garygid
Sparky,
I am trying to get a good / proper scaling for Volts and Amps
for both the SOC=Meter and for CAN-Do to display on its "dashboard".

From 1DB:
1. Probably Battery Pack Amps: D1 followed by top 3 bits of D2
to make an 11-bit 2's compliment signed integer. Scale?
Perhaps divide by 2 to get amps?

2. Probably Battery Pack Volts: D3 followed by top 3 bits of D4
to make an 11-bit unsigned integer. Scale?
Perhaps divide by 4 to get volts?

From 1DA:
1. Probably Motor RPM: D5 followed by 8 bits of D6
to make a 16-bit 2's compliment signed integer.
No scaling, is Revolutions per minute.

2. Probably Motor Power (or Amps):Low 3 bits of D3 followed by 8 bits of D4
to make an 11-bit 2's compliment signed integer.
This appears to be motor power (or amps), what scaling?

Thanks, Gary ... Nice Work and graphs!!