Dear Mohammed

You can only make approximate calculations. The nominal total energy in Your battery is: 12 V * 200Ah = 2400 Wh

So in consequence the maximum time to run this motor with full power is:

2.4 kWh / 3 kW = 0.8 h = 48 minutes.

But You don't need full motor power for the entire time.

To calculate approximate power needed to drive a cart You have to make more

complicated calculations and to have more data. For example speed and required accelaration.

This calculations I have already presaented when answering the question

of Vishva Pandya 4 monthe ago on Research Gate as well.

The question was: ' How to calculate BLDC motor rating for electric car, if.....'

You have to find this question and perform your own calculations with Your own data.

All the best and I hope that it will be usefull to You.

Piotr Wach, Opole, Poland

The answer should be based mainly on the roll friction of your vehicle. So as a first thing try to select wheel/tire. Then check the rolling resistance -> power to overcome the this force for given weight of vehicle -> time of operation with 2400Wh capacity available (with of course less than 100% efficiency).

Add some margin for acceleration and deceleration, but modern drives are able to recuperate energy during braking, so for long operation most important is constant rolling resistant force.

So finally the cart is on the test run and the findings are as follows

System info.

Battery volts 24 400 Amps

Motor 3.5 KVA

Reduction ratio motor to drive shaft 3:1

Reduction on drive axle 3.5:1

approximate weight of the cart with payload 375 kg

2 individuals / two batteries / cart all added p

1. when running idle wheels in the air current draw = 20 amps

2. when running with with full payload 50 amps at half speed 100 amps at fll speed.

in general not bad for the first test bt weight will be reduced with composite parts

instead of steel yet if it is considered as a regular feature based on the current draw , battery size has to be evaluated .

if(current draw==100amps) how much time will this cart run in real world senerio

Please enlighten me what all information is reqired.

motor running idle 16 amps

motor running when mounted 20 amps

Motor running with payload and slow speed 50 amps

Motor rnning top speed 100 amps on flat surface

I will appreciate if you may let me know what else to observe and calclate

regards

Mo

I think you should use a 60 to 72v BLDC motor with Lithium-Ion Battery pack to get enough speed.