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Formula Hybrid

28K views 73 replies 15 participants last post by  PStechPaul 
#1 ·
hey guys ,
for a car to accelerate and complete a distance of 200 under 6 to 8 seconds what type of motor can be used and tuned easily???
 
#4 ·
Do the calculations. Calculate the torque and power needed to accelerate a 300kg vehicle 200meters. Then come back and ask me if there's a motor that has that torque and power.

I can tell you YES, there is a motor that can do it, but it only races at 1/4mile at a time and does so in just under 7 seconds and goes 200mph.

If you need something for a longer race, things get more complicated. Cooling the motor becomes a huge issue.
 
#7 ·
I have done the calculations before and the calculations are like this..........
m=400kg
t=8s
distance to be covered is 200m
since the initial velocity is 0 the acceleration will be 6.25m/s^2
hence final velocity will be 50m/s
so the output required will be 400*50*6.25=125kw
which is so huge?? Am i wrong in calculations?? or is the parameters taken are wrong??
or is it not possible to get the required outputs???
 
#8 · (Edited)
I have done the calculations before and the calculations are like this..........
m=400kg
t=8s
distance to be covered is 200m
You said 300kg and 10 seconds to go 200m. That's quite a bit different from 400kg and 8 seconds... So which is it?

EDIT: 48kW for 300kg/10s/200m vs. 125kW for 400kg/8s/200m - that's the difference between only needing golf cart components or having to use mid-high level EV components.
 
#12 ·
What is the budget for batteries (and what monetary unit you're using)?

You said 6k, but didn't give units (which you need to start doing, using numbers with units is something an engineer should know how to do).

The battery pack is what I'd focus on. The 125kw motor is something doable, it's the battery pack that is going to be the hard part.
 
#16 · (Edited)
Let's see... You need 125kW of power - not including anything to make up for various inefficiencies - and you want to use a 72V pack... Sure, no problem, as long as the pack can deliver 1736A without sagging. :rolleyes:

Realistically speaking, you are going to need at least a 144V pack and a 1000A controller or a 288V pack and a 500-600A controller.

And if you want the RPM to be between 2500 and 3000 when delivering 125kW you are going to need a massive amount of torque - some 400-500Nm.

You can certainly get a motor and controller capable of dishing out 125kW for useful lengths of time, and for less than $6000US, but that won't leave you much for batteries. You may want to consider scaling back your performance goals and/or finding ways to reduce weight (though 400kg is already pretty light for a vehicle that will be driven on roads...).
 
#20 ·
Actually you got me wrong ......... The cap on the battery cost is 6000USD and there is no other cap on anything.................... And i got your point........... so can you suggest me on this??
if we are going for a LiFePO4 battery pack then what controller do you suggest???
 
#22 ·
I'm really sorry if i'm making you feel that you're doing homework for me ............. But though i may be knowing the things , it will be taken as a verification when you also suggest the same thing and they will be pretty much practical as you've worked on these kinds of stuff................The calculations even a small kid can do but we shouldn't be facing the practical problems later ........... If we face later then that time i can't come and ask in the forum. so i'm clearing everything out including very small stupid thing.......
 
#25 ·
The curtis controller is an Induction Motor controller with no support for BLDC motors. The Yasa 750 is a BLDC motor.

The 1238 series controllers are limited to 130VDC and 650A, but at 650A you'll have sag, so still, only expect about 80kw peak.

What lifepo4 pack? what batteries?
 
#30 ·
Ok, I am thinking he needs a place to start. Most people start here:

www.evalbum.com

You can see lots of examples and can search by battery brand, type, controller, etc. When you find cars that are similar in performance to what you want, take note of the components used, research their cost and capabilities.

Then you will know a little something.

There are many paths to what you seek. Do you merely want to meet the target? Or do you want to build something cool? You mention 72v pack. I think you must have forgot a zero and meant 720v, yes?

In America we call this humor..:cool:
 
#36 ·
Re: Power Adding

It's pretty simple on paper:

ICE + small Electric motor + main Electric motor - some frictional losses = power output
So what ever may be the speed , torque will match and the power output will be same ........ Hence in a race car does it really matter if we choose speed coupling or Torque coupling???

[/QUOTE]They also have clutches in between everything so mechanically it's obscenely complex but can produce up to 6 different driving configurations.[/QUOTE]

Okay here are you referring to planetary gear system?? If not with what kind of other system will we be able to get those many configurations???
 
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