I have four technic Large motor, all connected to a technic hub. I am using the motor to turn some large propellers and the hub is powered by six 1.5 V (maybe less) batteries. So each motor would get 9V, but the current would be 1/4 of a certain value. I want to increase the power supplied to each motor while use the same technic hub. I remember that according to the manual, the hub can handle 12V at most. Is this true? Can we increase the input voltage by connecting a more powerful battery to the hub?

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    The voltage doesn't drop by by a factor of 4 because 4 motors are powered, that's not how voltage works. I'd urge you to educate yourself in some basics of electric circuitry like ohms law, parallel and series circuits, electric power, etc... before considering the experiments you have in mind, for the safety of your Lego and your own safety... Perhaps you are still in school and your physics teacher can help you ? – Michael Verschaeve May 13 at 0:04
  • I forget the hub connect the motor in parallel. But still, the current in 1/4 of what it would be if there is only 1 motor connected to to hub. So the power to four motor is 1/4 of the power to 1 motor though? – user39178 May 13 at 16:03
  • If the hub can supply X Amperes of current at most (be it either the maximal sustained current or a short term burst value), then with four motors attached any of them can receive at most X/4 Amperes simultaneously - that part is correct. But each type of motor has its own maximum current it can consume, which is unrelated to X - might be lower than X/4, or between X/4 and X. (For Control+ L motors the stall current is 1.4A, but I couldn't find the current the Hub can support either per port or the total) – zovits May 13 at 16:40
  • Still quite incorrect. If the power consumption of your motors is below what the battery can supply, you will see NOT see a current drop of a factor 4. Current and hence power to each motor will be somewhat less because of internal resistance of the battery but depending on your motors resistance it could be hardly noticeable... Only thing you can say with certainty is that your battery will drain 4 times faster. – Michael Verschaeve May 13 at 23:02
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    No, in series that would mean 27 V, I read in some article that the motor controller IC can only handle 10.5 V. So that's the best you can do, i.e. add another 1.5 V battery to your original 6 in series, which buys you about 17% more power, I don't think it's worth the risk. – Michael Verschaeve May 16 at 15:56

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