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The sparks are normal too, as sir TrickyNekro said , its because of back emf. but try not to reverse the change motor's direction suddenly at higher speeds ( back emf is a function of speed)..
The DC motor you are using has probably high current demands ( i once used something similar, that took upto 3 amps at no load) so yes, no wonder the battery overheats. its supplying excess current in a short amount of time. if you can ,try getting a battery having greater mAh matching the current requirements of your motors. aside from lasting longer, they would stay cooler too (a battery's output is a function of temperature too) The sparks are normal too, as sir TrickyNekro said , its because of back emf. but try not to reverse the change motor's direction suddenly at higher speeds ( back emf is a function of speed)..
Sir?? haha, I'm at my 20ies not that old :-pThe truth is that back EMF is a function of current mainly, but can be of speed also.EMF = -DΦ/dt and Φ = LI. Where Φ is the magnetic flux through a surface, L is the inductance of the motor coil. I is current and t is time.... ;-)There are many things you want to consider before building a very good and efficient motor controller ;-)So yes actually it is a function of speed as DΦ/dt is higher at greater speeds but people miss most of the time is that EMF is not voltage.It's measured in volts but actually it's current delivering capability... ;-)
I was thinking about getting this....will this be to much for that motor? Or is it the motor that decides how much power it needs and handles itself? The battery says 40A discharge max...
haha im in my early twenties too, i just wrote that out of respect( thats what we use sometimes from where i come from),since i'm sure you must know shitloads more than me when it comes to robotics ( being a supremerobot and all that ) ...sorry if it felt otherwise and yes, i think i may have mis conveyed by saying it was a function of speed.What i really meant was that,generally, the greater the speed, greater the back emf.
The mAh( milli-amps per hour) rating is the amount of current a battery CAN supply in one hour( in this case 5000 mA), or twice that in half hour or four times that in 15 mins..etc. Its not something the battery will always supply regardless of the load. Motors should only draw the current they need to operate(unless there is a short-circuit). when they say 40A maximum discharge, it means don't connect anything with the battery that draws more current than that , else it could damage the battery it by overheating .