i'm working on a project and willing to use the L298N H-bridge to power 4 12v motors, each 2 placed in parallel with a current consumption of about 700 mA each that will be controlled by the Arduino PWM pins, as I've seen, this motor driver is able to supply 2A on each channel! so working it out, each 2 motors shall work with no problem, maybe some more heat to the Bridge, but i may use a fan directed toward that, wouldn't that help too? The continuous run time for this bridge will not exceed 5 min! I'll be using Lithium 18650 batteries, about 3000mAh capacity each, im wondering what is the voltage drop across the Bridge, so that i would know how much Batteries are needed! 1 more ques, how is the Bridge supplied to power the transistor inside? how can i supply it ?
Use 4 in series. The bridge drops 2V+.
The voltage drop across a 298, according to the datasheet, is 1.8 rising to 4.9 at 2A.
If it's the multiwatt package, you need to supply the 5V logic to pin 9, and the motor voltage to pin 4.
I have this L298N model, so assuming i supply it with 4, say around 4.2V 18650 batteries placed in series from the 12+ pin in the model, would that do the job? wouldnt that harm the motors if say the drop voltage wasn't exactly around 4 volts or so?
Here's OP's 298:
wouldnt that harm the motors if say the drop voltage wasn't exactly around 4 volts or so?
I suppose that depends on the motors, but it's the price you pay for using outdated technology. The 298 makes more sense at higher voltages, since the voltage drop although the same in absolute terms, is relatively less.
Newer drivers like these don't have the same voltage drop. There's a reason your one has that huge heat sink 
A rated 12V DCmotor can take much higer voltage than that.
You should check things: voltage/current/load if your motors gets very hot. 50degC +
knut_ny:
A rated 12V DCmotor can take much higer voltage than that.
You should check things: voltage/current/load if your motors gets very hot. 50degC +
1 more ques, hmm so would giving the motor more voltage rn than the rated one helps in increasing its performance, saying by about 4 volts or such, i may need that, my motors i suppose aren't cheap so would that help ?
The higher the voltage the shorter the brush and bearing life, stupidly high voltage could just burn it
out on no load of course, but thermal limit depends on the current, hence on the mechanical load.
Most motors will handle 50% more voltage without big problems, but they'll also run at 50% voltage
for a much longer life... swings and roundabouts.
Overspeeding a big motor could explode the rotor dangerously, but this is unlikely to be an
issue until you handle seriously powerful series-wound motors.