Powering 4 motors and 4 servos

Hi, I am working on an independent study for Arduino project in my school, and I'm struggling to find a correct way to power my project. Basically, it is a vehicle with four high torque motors.

I have to power four motors and four servos right now.
Here are the condensed specs for each of the parts.

170rpm Econ Gear DC Motor
Nominal Voltage: 12V
Current(No Load): 0.10A
Current(Stall): 3.8A

HS-785HB Servo
Nominal Voltage: 6V
Current Drain(No load) = 285mA
Current Drain(Idle) = 8.7mA

I will be using two MDD10A motor drivers which can use up to 10A per motor, with 10~35V.

So here's the part I'm struggling with.
Because I don't have a good electronics knowledge, I'm getting confused how to draw a circuit and arranging which to go parallel and which to go serial.

What I've thought of right now is powering with 12V 13A battery, give 6A each to motor drivers through parallel circuit(3A each to motor) and then use the 6V regulator to drop the voltage down and supplying it to four parallel connected servos.

I'm sorry that I have to explain all of this through words, not a circuit diagram.
I wanted to make sure if the idea I have right now is correct.

For that much power, sealed acid battery(Car battery) is the only one I could think of. But because I need everything to be light enough for motors to handle, I was wondering if there could be better ways to arrange the circuit and find a better motor.

Thank you!

There is not really any such thing as a "12V 13A battery". Perhaps you mean 12V 13Ah which is very different but unless you provide links to exactly what you are talking about we're just guessing. If you want a lighter battery then a 3S 11.1V Lipo will probably work out a lot better.

You've given no details about "the 6V regulator". If it is a switch-mode DC-DC converter, fine. If it is a linear regulator, I wouldn't.

But in general one battery powering both motor drivers and then through a 6V converter the servos is fine. How are you intending to power the Arduino?


For the arduino, I'm thinking of just putting an extra power supply since they don't need much power as motors do. Or I can use the power regulated to 6V(for servos) to supply arduino as well.

Because I'm a real beginner to arduino, I'm unsure what you're talking about.

  1. What's the difference between the switch mode regulaor and a linear regulator?? All I need is to lower the voltage to supply the servos.

  2. Yes, I thought of the Lipo battery packs, but I was unsure if it can supply enough amps for all the motors. But I still have to find a way to provide around 12A in total, right? Or should I connect several batteries in parallel to boost the amps? What kind of battery does people usually use to power these high-torque motors?

  3. What do you mean by exact links? The only plan/information I have right now is the specs for motors and servos, and I just need to find a right way to arrange the circuits and power them

I really appreciate your help!

  1. Linear regulators burn up the excess voltage as waste heat. Switched regulators don't. What "6V regulator" were you planning to use?

  2. Many lipo batteries can provide MUCH more current than you need. E.g. Zippy flightmax 3000mah 40c Theoretical maximum 120A (3 x 40).

  3. Back in March you knew how to put links in your posts pointing to the components you were going to use. Why can you no longer do that?


  1. That was the part I'm confused about. Because I don't have the basic foundation on electronics, I'm totally lost which regulator to use and how to hook it up to circuit. For now, I'm trying to teach myself by starting to use the 'fritzing' program. Are there any suggestions for the regulators!

  2. Thanks! I should probably use that. So I need to find the one with appropriate discharge rate so it can supply around 13A, right? Or is it ok for the battery to be a little over 13A?(like 20A) I just don't want the battery to be overkill.

  3. Oh I misunderstood, here's the link for the motors

Servo: HS-785HB Servo - ServoCity
Servo Gearbox(Mine is 5:1 Ratio): https://www.servocity.com/tm-785hb-servo-gearbox
170RPM Econ Gear Motor: 170 RPM Econ Gear Motor - ServoCity

Thank you so much for helping out. It really clarified a lot of questions I had.
Lastly, are there any suggestions on how to circuit this? I want to ask if my plan(what I wrote on the first post) makes sense

Any battery that can supply at least say 15A will be fine. A battery like the one I posted would be perfectly o.k. but you don't need quite that much. You do need to know how long you expect it to run for before it needs recharging. That's how you decide what battery capacity (mAh) you need.

That servo gearbox you pointed to already includes a servo. So do you have some of those plus another 4 servos?

I can't really give much advice on how everything should be connected without some idea of what the project is supposed to be and do.