[kishor5466]

The one for 400Kg/8s/200m

[frodus]

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.

[kishor5466]

i think i had mentioned it as 6000$ ...............

[frodus]

US dollars though, right? I just want to make sure others knew, you mentioned that to me in PM's.

[kishor5466]

yep,
it is 6000 USD........ and don't you think that with a 72 V pack we will be able to get the required power and torque..................

[Tesseract]

Originally Posted by kishor5466

yep,
it is 6000 USD........ and don't you think that with a 72 V pack we will be able to get the required power and torque..................

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.

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...).

[major]

Originally Posted by kishor5466

....... and don't you think that with a 72 V pack we will be able to get the required power and torque..................

Hi kishor,

You really should start doing some of these calculations. That is an important part of engineering education. I've seen the figure of 125kW, so simple math says you'd need 1736 Amperes from a 72 Volt battery. Do you think that is realistic? If so, you had better read up on the subject.

Also, a 72V battery will sag and not deliver a full 72V under load. The 125kW used was a battery output and does not account for drivetrain loss. And the 125kW was an average power over the acceleration period, so in reality, peak power will be higher.

Good luck,

major

[frodus]

Sure, you could get 125kw with a 72V pack, but your batteries need to be able to supply well over 1700Amps to hit that 125,000W mark.

It keeps sounding like we're doing this homework for you.

[frodus]

Originally Posted by Tesseract

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...).

The $6000USD is apparently for battery only.

[kishor5466]

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???