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whats the best motor and ESC to use for a high torque r/c tank?

i am currently building an r/c tank, but i am having trouble finding a suitable motor and ESC that will allow it to go realy fast ( high speed tank).
all i can find are brushless motors that require 30A at 6-12v, the same goes for the esc's, and i have no idea were to get that sort of power as i only have access to a 9.6v 750ma battery but i can get sealed, lead-acid batteries, at around 12v and 3amps, but thats still nowhere near what i need.

does anyone know where i can get a brushless motor that can have at least 30kg of torque @ at least 1500rpm, that can run off 1A 9V?

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I am currently trying something similar, but a bit bigger. I resourced an old electric wheelchair, which has 2 x 12.5 Amp motors. In my case, additional weight is desired, so the batteries will only help in that respect. This is good, since the design will call for 2 x 12v auto batteries.

The reason I chose (to stay) at 12v was mainly that the existing chair electronics were designed to run off either 12v or 24v. The various needs I will have for +9v and +5v can be supplied by the batteries connected to voltage regulators or voltage divider circuits.

If I was working from 100% scratch, I would probably base it off of +12v. To me, it's more versatile.

It's been a couple of years since you posted this. Was really interested if you finished it!

Huck
oldmanbeefjerky (author)  huck alexander4 years ago
unfortunately no, i wasnt able to source any actual parts to build the tank with, also, nobody has been able to help me find an AM receiver and transmitter pair to use to operate either side, so now im building it from lego instead, with a super basic design.
eventually ill try again once i get a 3d printer
look on a mainhobbies.com because u could u a 2 stick controller like the ones used for boats for under 100$ allowing u to control one tread with one stick and a another tread with the other look for the ones above 5 channels
gmxx6 years ago
With the specs you require, its not going to be possible, at least not cheaply. the kind of power you need comes from batteries used in cars or power chairs. your power supply is essentialy equal to a 9v battery. 

As for the drive, a fast moving tank is going to be difficult. tanks are designed to be slow veichles that can go over anything. If they were well suited to going fast, then they would speed along in real life.  Motors tend to either be slow, with a lot of torque or fast with almost no torque. 


oldmanbeefjerky (author)  gmxx6 years ago
well money for my tank wont be much of a hassle, i can get stuff from jaycar rather cheaply since i am taking a robotics course at school (govement discounts) i dont care that it is expensive, just tell me what voltage i should use (battery+voltage amps) what (type)motor should i use what type of esc should i use all of which for a tank expected now to weigh 2kg and go at a reasonable speed , not racing fast, but not slow either i need to know what to buy ( including amount a motor should step down by gears) currently i have access to a 6v dc high speed motor that has 20,000 rpm and 2kg.com of torque and sla batttery as mentioned above
before i get into details, how big is the tank going to be roughly?
oldmanbeefjerky (author)  gmxx6 years ago
big enough to place the sla battery in the centre (making it the center of gravity of the tank so it wont effect the balance)10x15x15cm, and the relays (about 5 or so), and the rc reciever , which is flat and 10x10cm all up ide say ited be 30-45cm long and 20 -30cm wide and 15 max high, but it will include multiple layers for different wiring ,circutry and such, the wieght should be about 2kg max, considering im using thermo plastics and sheet aluminium to build the body if it were a proper r/c tank (store bought) ited say 1/12 scale model why did you want to kow? and also, when i asked this question i wanted to know the specs of a real ( or theoretical) speed controller and motor, or better yet, the kind of motor and power combination required to move a 2kg tank at a minimum of 5-7cm per second , while at the same time having the force to move over and through dragging terain like a slope ( if done the slopes and enegy mathematics at school), at which time ide say that would be the torque, so it should have enough torque after moving itself to move up a slope of 30 degrees is that information obtainable from the energy produces by a motor and the suitable power source from which it is used on? btw i do plan on stepping the motor down with gears
i just want to know what im helping with. specs for parts and stuff will be different for a small robot compared to one you would ride on. i have built something similar, except it does not use tank drive. i would start with an electronic wheel chair speed controller and motors. this will probably be the best start for you. you can custom design an arduino-esque control system, or just use an rc receiver. the other option, is the sabertooth 2x25 speed controllers. then find some cim motors or similar to use. this would be cheaper, but would require more design time. i have personally done both options, and prefer the cheaper design. $260 is going to be a tight budget for this. what level of experience do you have?
oldmanbeefjerky (author)  gmxx6 years ago
money is not much of an issue, i am willing to pay up to $260n the motor esc and battery all up
I suspect you can't. What torque are you looking for ? The kilogram is not a unit of torque ! If I assume you mean kg.cm, then you are asking for 2.94 Nm of torque, or 2.94 x 1500/60 or 74.5 Watts ! You can't DO that ! Your source can only supply 9 Watts.
oldmanbeefjerky (author)  steveastrouk6 years ago
no, i said it can only supplie 3 wats.

what i want is for my tank ( which will wight aprroximately 1-2kg) to be able to move very fast like a standard toy r/c car (aka not slow) , while still being ables to move over objects, and through terain (e.g grass,sand)like a tank would without running out of power since i cannot add gears.

sort of like a supercharged tank that is fast and has a high torque , but only a liitle more torque than what it would possibly ever need, so wouldnt that be 5kg of torque?
No, torque is the product of a force x distance - a leverage if you like. There's no easy way to calculate the requreiments of your drive train.

You can extract a lot more than 3A from a SLA battery. They will easily supply 30A, but for only 1/10 th of the time that they can supply 3.

The drive will only demand the 30A MAXIMUM when it needs it anyway, not continuously.
oldmanbeefjerky (author)  steveastrouk6 years ago
so what your saying is that the esc and motors that say they are built for 30A means that they take up to and handle up to 30A but can run off any voltage or current?
They don't "run" on a current, the motor requires a current which, up to 30 A the ESC can supply. They work on 6-12V though, because the rest of the electronics needs a certain operating voltage