I connected 4 motors with L293D motor shield and stack the shield with 1sheeld and arduino UNO R3 board.I use only 9v battery to supply my car through EXT_PWR in motor shield , only 1 motor works but it runs very weak.When i connect 4 9v battery together and connect it to EXT_PWR , 4 motor works but it works extremely slow.Is using package of 2 18650 batteries (3,7V,1100mAh,2A) a solution for this problem ? Because i have asked many people and they said that 9v battery is too weak to power 4 motors.
Here is the statitics of my motors:
*Operating voltage:3-9VDC
*Consumes 110-140mA
9V battery is hopeless for motors, motors usually require amps, not just milliamps.
You need to know what current your motors need, that depends on the motors in question.
The power source needs to be able to provide enough current, whether 2A is enough
depends on whether each motor can run with only 0.5A, which appears to be the case here.
Note that your motors will briefly take a lot more than 0.14A on starting, but that's not
usually an issue with a battery (some power supplies can trip-out on over current,
batteries just struggle on (unless certain lithium batteries with built-in protection circuit))