# 0-60 estimates.



## gsmith191145 (May 1, 2011)

It is easiest to convert to metric then convert back.

This will get you meters per second.

acceleration= Force/mass

This formula will get you Force
Motor torque and tire radius

Torque Nm /radius m = Force

Mass should be self explanatory.

Then convert into hours and miles.


----------



## efan (Aug 27, 2009)

you can try using this calculator:

*http://www.060calculator.com/*


----------



## dladd (Jun 1, 2011)

well that's the confusing part to me. I understand F=ma, and I know in the ICE world I'd need roughly 100 horsepower, but I don't know how that translates to electric motors. 

So, using a concrete example, how would I determine the 'horsepower' equivalent (is there such a thing for ev's?) for a 2500lb car running a transmission, a Warp 9, a Soliton Jr (600a), and 48 100a CALB's (144v)? What would be that cars 0-40? 0-60?


----------



## Guest (Aug 20, 2011)

My Leaf will do 0-60 in 9 seconds. AC drive and 24KW pack. This car really scoots along nicely. Not a hot rod but very capable. I would not be surprised if it did 0-60 in 8 seconds.

Pete


----------



## efan (Aug 27, 2009)

dladd said:


> well that's the confusing part to me. I understand F=ma, and I know in the ICE world I'd need roughly 100 horsepower, but I don't know how that translates to electric motors.
> 
> So, using a concrete example, how would I determine the 'horsepower' equivalent (is there such a thing for ev's?) for a 2500lb car running a transmission, a Warp 9, a Soliton Jr (600a), and 48 100a CALB's (144v)? What would be that cars 0-40? 0-60?


so you would have:
48 * 3.2 = 153.6v
153.6 * 600 = 92.16kw * 0.8 (due to sag, efficiency of motor and controller etc.) ~ 73 kw (approximately) 
so your power is around 73kw plugging this into the calculator (FWD, 2500lb) gives 0 to 60 of 10.3 seconds 
I am not saying you will get exactly this result, but it is a good indication.

in case you need it: 1hp = 745.7watts
and you can calculate your power in watts by Voltage * Current


----------



## dladd (Jun 1, 2011)

efan said:


> so you would have:
> 48 * 3.2 = 153.6v
> 153.6 * 600 = 92.16kw * 0.8 (due to sag, efficiency of motor and controller etc.) ~ 73 kw (approximately)
> so your power is around 73kw plugging this into the calculator (FWD, 2500lb) gives 0 to 60 of 10.3 seconds
> ...


Exactly what I was looking for, thanks!!!

I see where I messed up in my thinking, I was thinking that packs of similar overall size (V x Ah) would result in similar rates of acceleration. 

Sadly, this all basically means AC is out.  I like it for it's general elegance (regen), and am willing to pay a little more for it, but the step from an AC-50 to the next up AC drive system is too much for me. DC it is!


----------



## dladd (Jun 1, 2011)

gottdi said:


> My Leaf will do 0-60 in 9 seconds. AC drive and 24KW pack. This car really scoots along nicely. Not a hot rod but very capable. I would not be surprised if it did 0-60 in 8 seconds.
> 
> Pete


I guess the part that surprised me is that 0-60 in 9 seconds is considered scooting along nicely in the EV world. My minivan does that, and it's, well, a 5000 pound minivan! Not exactly what I call fast... To see that an EV similar to what I was planning could only do 16 seconds was tough to take.


----------



## gsmith191145 (May 1, 2011)

I would need your tire info to give you what you need. the motor torque specs are on the internet. The physics is the easy part. Please fill in the blanks

First, lets convert all measurments to metric. 2500 lbs = 1134 kg. (the radius of your tires) = ? 

(circumference of tires) = ?

95 Nm / (Tire Radius)= N

N/ 1134kg = m/s/s of acceleration

Multiply the circumference of the tires by the RPM of the tires. 

(circumference)* 5500RPM need more info to complete your answer


----------



## spdas (Nov 28, 2009)

My 2300# Yaris with 46x 180ah calbs, zilla, warp9 easily outruns an ICE Yaris.
I can't give u any times as it is a 5sp standard and I do not use the clutch to shift, so gear changes are incredibly slow. But 0-40 is 4-5 seconds if I start and stay in 2nd. So I would guess 8-9-10 seconds 0-60.

Francis


----------



## tomofreno (Mar 3, 2009)

> I'm a little disheartened to see that the SwiftE (with AC-50) does a 0-60 in 16 seconds (similar car to what I'm thinking). I did a little testing with a stopwatch today, my minivan does 0-40 in 5 seconds, and 0-60 in 9 seconds. These would be reasonable numbers for me, but not much slower. I could deal with 10-11 seconds to 60, but not slower than 5 seconds getting to 40.


That's right, I (the SwiftE owner) did zero to 60 tests with a data logging GPS recording distance and velocity. Took about 9 seconds to 40 mph and 16 seconds to 60 mph. Yes you will get similar performance with a 8" or 9" motor, a controller with the same max current, and similar battery pack voltage. See here:
http://www.diyelectriccar.com/forums/showpost.php?p=253358&postcount=311
The torque-speed curves Jack R posted for the AC50 from dyno data agree well with the calculated ones in the above post.

If you want 10 seconds or less zero to 60 you'll need a higher amp controller like the Soliton1 or Zilla. Or remove several hundred pounds from your car. Jack Rickard claims about 11 seconds for his about 2000 lb Porsche Speedster replica if I recall correctly. A higher voltage controller will also help since it will move the "knee" of the torque-speed curve out to higher rpm. It won't help as much as a larger current controller though, since it won't increase your torque at lower rpms.


----------



## dladd (Jun 1, 2011)

tomofreno said:


> That's right, I (the SwiftE owner) did zero to 60 tests with a data logging GPS recording distance and velocity. Took about 9 seconds to 40 mph and 16 seconds to 60 mph.


And I really appreciate that you took the time to not only test this, but post the data to help others out!



tomofreno said:


> A higher voltage controller will also help since it will move the "knee" of the torque-speed curve out to higher rpm. It won't help as much as a larger current controller though, since it won't increase your torque at lower rpms.


What do you mean by the 'knee'? I've seen that mentioned before in regards to setting battery charge limits, not sure what it means.

lets see if I understand this all a little better now... 

If I up the voltage from 144 to 192v with a 600a DC controller (Soliton Jr for example) I increase my avaliable power from ~70kw to ~92kw and still stay at 6c max. But I'm still limited to 600a at the motor right? So will I see much difference off the line?

If I go up to 192v with a 1000a controller set to limit battery amps to 600 I also have the same power avaliable, but will get more amps at lower motor rpm's resulting in a harder launch, right? Where is the crossover? Is it a big difference? Like .5 seconds, or like 5 seconds of added amps before the motor voltage increases to where they would be the same?

Am I making sense?


----------



## EVfun (Mar 14, 2010)

> If I up the voltage from 144 to 192v with a 600a DC controller (Soliton Jr for example) I increase my avaliable power from ~70kw to ~92kw and still stay at 6c max. But I'm still limited to 600a at the motor right? So will I see much difference off the line?


You will see little difference off the line. However, EVs rarely suffer from a lack of jump off the line. In fact, most EVs start take off from a stop in 2nd gear to tame the low end torque jump.

What you will see is acceleration continuing to a higher rpm before you cross peak power and acceleration begins to wane. It will delay the need to shift. This will improve performance because when you shift you get the motor the full motor torque back, but you apply it to the ground with less multiplication. So, more voltage will improve your 0-60 mph times. 



> If I go up to 192v with a 1000a controller set to limit battery amps to 600 I also have the same power avaliable, but will get more amps at lower motor rpm's resulting in a harder launch, right? Where is the crossover? Is it a big difference? Like .5 seconds, or like 5 seconds of added amps before the motor voltage increases to where they would be the same?


That will improve your launch. It is almost like an electric transmission that is automatic and has a zero shift time. You get more low end torque and retain the peak power point based on the voltage and battery amps allowed. It creates a broader, flatter, power curve. I don't know how to quantify the difference.


----------



## tomofreno (Mar 3, 2009)

> What do you mean by the 'knee'? I've seen that mentioned before in regards to setting battery charge limits, not sure what it means.


 Look at the wheel torque versus vehicle speed curves at the link I gave. You see wheel torque is constant out to a certain vehicle speed (and motor rpm), then it starts to decrease with increasing vehicle speed and motor rpm. The inflection point where it starts to decrease is sometimes called the knee of the curve. The flat part is your femur, the decreasing part is your shin bone. Motor input impedance increases with rpm, so more voltage is required to push a given current through the motor at higher rpm and vehicle speed (in a given gear). You are limited by the pack voltage, and current and torque start decreasing once that limit is reached. That's the knee. It can be moved out to higher rpm by increasing the pack voltage (as long as the controller can handle it). EVfun already explained the affect of this - you maintain peak motor torque out to higher rpm, sustaining higher acceleration out to higher rpm, increasing power.


> If I go up to 192v with a 1000a controller set to limit battery amps to 600 I also have the same power available, but will get more amps at lower motor rpm's resulting in a harder launch, right?


 Yes, since you will get the max current output of the controller at lower motor rpm where the motor input impedance is lower.


> Where is the crossover? Is it a big difference? Like .5 seconds, or like 5 seconds of added amps before the motor voltage increases to where they would be the same?


 By "crossover" I guess you mean when will the acceleration in the two scenarios be equal? I don't know how many seconds that will be. I would guess "a few" like 3 seconds, not 0.5. It will increase acceleration considerably if you can prevent the tires from spinning - not easy with 1000A and a 2500 lb vehicle.

Edit 1: A local guy has a Ford Festiva with Warp9 and Zilla 1k controller with max battery amps set to 500A. He told me it does zero to 60 in 9 seconds, and would do better if he could keep the tires from spinning.

Edit 2:Torque increases fairly linearly with motor current, and the force the tires apply to the road is wheel torque divided by (loaded) tire radius. So wheel torque, equal the product of motor torque and overall gear ratio, is what accelerates the car. Maintaining high torque to high rpm requires high power output since motor shaft power is the product of motor torque, motor rpm, and some constants. That is what a controller than can handle both high voltage and high current gives you. The 1kA will give high acceleration at lower rpm. To maintain that rate to higher rpm requires a higher voltage pack and controller (that can put out 1kA).


----------



## gor (Nov 25, 2009)

*Re: 0-60 estimates - slip torque*

for regular road (street) tires - slip torque - up to 1 of weight on wheels and 1.4 with wheel spin?


----------



## Duncan (Dec 8, 2008)

*Re: 0-60 estimates - slip torque*

Hi Gor

_for regular road (street) tires - slip torque - up to 1 of weight on wheels and 1.4 with wheel spin?

_No 
look for 0.8 max with less if you spin the wheels


----------



## gor (Nov 25, 2009)

*Re: 0-60 estimates - slip torque*



Duncan said:


> Hi Gor
> 
> _for regular road (street) tires - slip torque - up to 1 of weight on wheels and 1.4 with wheel spin?_
> 
> ...


that's what teach in school, then in reality max a would = g (or 0.8g) for 4WD and half for 2WD; g=9.8 m/s=36km/h; so, for 4WD and 1g:
1s-36km/h
2s-72km/h
3s- 108km/h(67mph)

2wd 50/50 weight distribution would do twice less than that -0-67mph in 6 sec- which is not the case: 0-60 under 5sec (3-4.5 sec) - common for performance cars on street tires


----------



## dladd (Jun 1, 2011)

For the purposes of this thread, fwd, rwd, tire sizes etc don't matter. I'm talking about very modest numbers here, like 0-60 in 9 seconds. No wheelspin needed. Also safe to assume tires, gearing etc that will keep the motor in it's normal efficiency range.

I think I have it pretty narrowed down now, aiming for 2500#, 1000a controller, 9" motor and 144 volts. A pretty tried a and true combo, no need to reinvent the wheel, right? Once I ruled out AC, it got pretty simple...


----------



## gor (Nov 25, 2009)

slip torque - still unavoidable question, - how much torque you can put to the ground and not loose traction, at what gear (gear ratio), power reqirements, torqe and speed 

another real-world example: 
if tires can stop, deselerate car 60-0 in 3 sec - they can accelerate 0-60; positive or neg. G...










v=s/t; (s=v/t)
t=s/v
0-60; V average= 30mph;( if t=3sec. Vave*t=S; 3s*30mph=90ft)
t= 104ft /30mph ave= 3.46sec; (S=Vave/t = 3.46 *30=104)
t1=125ft/30mph= 4.16 sec 60-0



gor said:


> that's what teach in school, then in reality max a would = g (or 0.8g) for 4WD and half for 2WD; g=9.8 m/s=36km/h; so, for 4WD and 1g:
> 1s-36km/h
> 2s-72km/h
> 3s- 108km/h(67mph)
> ...


----------



## EVfun (Mar 14, 2010)

gor said:


> another real-world example:
> if tires can stop, deselerate car 60-0 in 3 sec - they can accelerate 0-60; positive or neg. G...


Only if you are planning an all wheel drive EV. It will be less if you compare 2 wheel drive to 4 wheel braking.


----------



## DavidDymaxion (Dec 1, 2008)

*Re: 0-60 estimates - slip torque*

There are street tires, and then there are street tires... Some are definitely much better than others. My gasser has pulled 0.54 g accelerating, 0.9 g stopping, and 1.03 g corning, on very good street tires (per a g-tech).

The 2nd thing to realize is weight transfer. Even though my gasser has only 45% of the weight on the rear wheels statically, it has more force than that under heavy acceleration (weight transfer), hence being able to do 0.54g on a tire with only 0.45*weight of force on it statically.

An extreme example of weight transfer is the purpose built drag racer pulling a little wheely, then 100% of the weight is on the rear wheels, so it can accelerate at a much faster rate than 0.5 g.


gor said:


> that's what teach in school, then in reality max a would = g (or 0.8g) for 4WD and half for 2WD; g=9.8 m/s=36km/h; so, for 4WD and 1g:
> 1s-36km/h
> 2s-72km/h
> 3s- 108km/h(67mph)
> ...


----------



## gor (Nov 25, 2009)

EVfun said:


> Only if you are planning an all wheel drive EV. It will be less if you compare 2 wheel drive to 4 wheel braking.


and what about 3-4.5 sec 0-60 instead of 5-6 for 2wd cars ?

p.s. i mean not drag or f1 tires, with koeff. up to 4.0 - but performance cars, pulling 3-4.5 sec. on tests and on the street; tires - good street racing class tires


----------



## EVfun (Mar 14, 2010)

gor said:


> and what about 3-4.5 sec 0-60 instead of 5-6 for 2wd cars ?


What about it? I was just pointing out that you where making an apples to oranges comparison unless you are planning an AWD conversion. 

I've seen a 2wd street EV pull 2 second 0-60 times on the track (on DOT street tires.)


----------



## Bowser330 (Jun 15, 2008)

EVfun said:


> What about it? I was just pointing out that you where making an apples to oranges comparison unless you are planning an AWD conversion.
> 
> I've seen a 2wd street EV pull 2 second 0-60 times on the track (on DOT street tires.)


What street EV are you talking about? How much suspension and driveline work does this street EV have? Im assuming it has a pretty expensive built rear-end.


----------



## Duncan (Dec 8, 2008)

*Re: 0-60 estimates - slip torque*

Hi Gor 

_0-60 under 5sec (3-4.5 sec) common for performance cars on street tires_

That's NOT "common" - it is achievable but those "street tires" cost as much as my car and only last 5,000 miles - or one event!

For street tires such as are fitted to normal cars 0.8 is about your lot! - you are getting into Porsche territory to get anything better


----------



## gor (Nov 25, 2009)

EVfun said:


> What about it? I was just pointing out that you where making an apples to oranges comparison unless you are planning an AWD conversion.
> 
> *I've seen a 2wd street EV pull 2 second 0-60 times on the track (on DOT street tires.)*


i know what you been pointing (60-0 - 4wheels involved) that's why i point on 0-60 for 2wd 
and you gave pretty good answer; 
so, if 0-60 in 2-4 sec, friction koeff on street tires > 1.0 (slip torque > weight on tires)


p.s. there are lot of threads like *"*What's your 0-60 MPH time on STANDARD STREET TIRES?" http://forums.corvetteforum.com/per...r-0-60-mph-time-on-standard-street-tires.html in many forums 
0-60mph or 0-60 ft times shows - some street tires pulling pretty good Gs, > 1.0 koef


----------



## notailpipe (May 25, 2010)

dladd said:


> I'm a little stuck on predicting acceleration times now. Not many folks in the Evalbum have any 0-40 or 0-60 times listed, and 'faster than a city bus' or 'quite brisk' don't really mean much to me...
> 
> In addition to building a nice daily driver, I want it to impress people who don't realize EV's can be quick.
> 
> Is there a generic 'rule of thumb' or calulator out there which will predict 0-40 or 0-60 type times for ev's? I've seen stuff for predicting top speeds and range estimates, but not for acceleration.


Dladd,

I've thought about what you're saying a lot and unfortunately I don't think anyone can really answer it. All the online/downloadable calculators or physics formulas gave me wildly varying answers. 

A few conclusions I've made is: go DC (seems like you already reached that conclusion). The extra range from regen isn't worth the extra cost/complexity yet. You can dump all that extra money into more batteries and extend your range. At the end of the day it seems to be limited by budget, so I'd get the most battery you can afford and focus the rest of your efforts on low-cost solutions to reduce weight and improve aerodynamics.

My aero plans for the 'Rex:
-underbelly pan to reduce turbulence
-lowered the car 1.5 inches (not too much to look rice, but will help)
-front racing lip (okay, it's a little rice, haha) to deflect air around the side and not under the car
-dam up the front radiator so air doesn't go into your engine bay (turbulence again)
-antenna delete (got an internal FM antenna that hides up behind my sun visor
-rear windshield wiper delete. Don't really use it ever, looks cleaner (your car may not have one), and I estimate it removes 0.01 from Cdrag
-Decided to keep the mirrors, not worth the safety risk (but looked up the laws and would be legal in my state to delete them)

Aero will be huge effects at high speeds, but this will help range more than acceleration. For acceleration, focus on weight. This is where I haven't done much. I don't believe in sacrificing comfort (not a whole lot in a CRX to begin with) for a few pounds here or there. In most cases I'm actually adding weight, like cupholders or sound deadener.. haha 

If you have a good motor and controller, then just spend as much as you can on the batteries and call it a day. It's not textbook engineering, but it is real-world engineering. That's my plan. 

Good luck.


----------



## gor (Nov 25, 2009)

there are a lot of sources to make acceleration calculations here and on the web:
http://vlsicad.ucsd.edu/~sharma/Potpourri/perf_est.html
http://buggies.builtforfun.co.uk/Calculator/index-imperial.html
nice ev calculator- http://www.diyelectriccar.com/forums/showthread.php/yes-another-ev-calculator-45278.html
http://electricnevada.org EV_calculator_rev5.09_Excel97.xls
http://www.diyelectriccar.com/forums/showthread.php/spreadsheet-compare-donor-cars-52097.html


basically power requirements to move 2000lbs vehicle at60 mph w/o accel - about 20kw (air drag, roll.resist, etc)
power only to accelerate vehicle:

*0-60mph in10sec*:
p=mva
a= 60mph/10s=6mph/s =2.682235m/s^2=0.27351g


1mph/s=0.447m/s^2
10mph/s=4.47m/s^2=14.6667ft/s=0.455853g
g=9.8m/s^2=21.93689mph/s

m=1000kg=2204.62lbs

p=mva=1000kg * 13.41m/s(30mph) *2.682235m/s^2=35,938.8w~*36kw*=48.28hp
----------
*0-60mph in 6sec: *
a=10mph/s=4.47m/s^2
at30mph (13.41m/s):
p=mva= 1000kg*13.41m/s*4.47m/s^2=59,942.7w~*60kw*=80.46hp

power (hp)=torque(ft-lbs)*rpm/5252; >> torque= power(hp)*5252/rpm
power (kw)=torque(nm)*rpm/9550


----------



## gor (Nov 25, 2009)

1.3L sz.swift [email protected]; 75ft-lbs @3000 
accel with org. ice would look something like this (pict)

we can try diff. motors, gears, power settings and see how it goes (i'll add motors, batts,etc and post spreadsheet)


----------



## dtbaker (Jan 5, 2008)

The other thing to take into account is that many of the EVs build for 'around town' don't usually SEE 60mph. I know that 90% of my daily driving I never go over 45mph, so the 0-35 really is what I look at in terms of 'keeping up with traffic' or even comparing to how the car felt as an ICE.

so... even though magazines and spec sheets are usually 0-60 times, I would suggest that 0-35 times are what you might want to consider for urban/suburban driving feel.

I know that my little Swift ,with 8" ADC, 120v Lithium, and (wimpy) curtis 1221 controller feel just about the same as stock 0-35 and perhaps better. If I had a beefier controller to kick out some more amps for max accel, I think it would be about all the original transmission could handle.


----------



## gor (Nov 25, 2009)

geo-metro / sz swift 1.3L 79hp 0-60 power, tq curves, ET, accel, distance, etc

some things to play with: 
spreadsheet: ev, ice, ev+ice (hybrid) performance; tranny and/or direct drive; variable ratios, A, V - have fun : )))


----------



## tomofreno (Mar 3, 2009)

Same car with AC50 motor/Curtis 1238-7501 controller, 115V nominal pack of CALB cells, calculated torque and power:
View attachment AC50 torque and power curves.pdf


----------



## tomofreno (Mar 3, 2009)

Where did you get your value of 3.58 for the final drive ratio? I got 3.79 here:
http://www.speedwheels.com/suzuki/2001-suzuki-swift-mod1216.html#specifications


----------



## gor (Nov 25, 2009)

http://www.teamswift.net/viewtopic.php?t=23748

2001 Suzuki Swift
H.P. = 79 @ 6000 motor rpm, max torque = 70 lb-ft at 3000 motor rpm for a 2001 Suzuki Swift with 1.3 liter 
1.3 SOHC
Torque: 75 ft-lbs. @ 3000 rpm Horsepower: 79 hp @ 6000 rpm
Manual transmission, only 1.3 
1st: 3.416 
2nd: 1.894 
3rd: 1.375 
4th: 1.030 
5th: 0.870 
R: 3.272 

diff:
1.3L SOHC: 3.523 
1.3L SOHC/FWD: 3.944 
1.3L DOHC: 4.105 
Manual transmission all except1.3 DOHC except all FWD, except all 1.6L: 
1st gear: 3.416 (revised to 3.58:1 on US 1.3L 1995+ only ?) 
2nd. gear 1.894 
3rd gear: 1.280 
4th gear: 0.914 
5th gear: 0.757 
Reverse: 3.272


----------



## Thaniel (May 25, 2008)

*Re: 0-60 estimates - slip torque*



Duncan said:


> Hi Gor
> 
> _0-60 under 5sec (3-4.5 sec) common for performance cars on street tires_
> 
> ...


Maybe more like 12,000 miles. At least on my ICE car with street tires which can do 0-60 in 4.5 or less  And the tires aren't even all that wide (225). And no the tires aren't that expensive. $130 each or there about. Performance can be had for not a lot of money if not going with crazy exotic stuff.


----------

