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Old 10-13-2013, 06:32 PM   #1
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Default basic motor and esc question

I am new to rc vehicles and need some help. one of Our motors required us to use a 12s rated battery. we purchased a large one hoping that it would work with 2 smaller 8s brushless motors in parallel. Is my understanding of an esc as just a voltage amplifier incorrect and is it possible to run these lower voltage rated motors with the higher voltage rated battery and just a lower throttle? the other option is to use the 6s connections on the battery for the 8s motors with lower performance.
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Old 10-14-2013, 08:47 AM   #2
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parts:
2 Turnigy SK3 Fandrive Brushless EDF Motor - 3968-1500KV (8S 90mm EDF)
2 Turnigy dlux 120A HV Brushless Speed Controller (OPTO)
1 Turnigy nano-tech A-SPEC 5000mah 12S 65~130C Lipo Pack
1 leopard LBP5692/4D
1 castle creations hydra ice 200A

the leopard and hydra esc work fine. We're just trying to get the two smaller turnigy motors to work with the same battery pack
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Old 10-14-2013, 09:31 AM   #3
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12S is not a rating. S = the number of cells (wired in series) of a battery pack.

ESC is not an amplifier. An ESC takes a direct current source as an input and "pulses" the voltage on and off to the motor.

The components you listed are not typically/ever used in RC on road cars. Perhaps you are posting in the wrong forum?
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Last edited by 240Z; 10-14-2013 at 01:41 PM. Reason: S "rating"
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Old 10-14-2013, 10:25 AM   #4
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The components you listed are not typically/ever used in RC on road cars. Perhaps you are posting in the wrong forum?
this. motors (that ive seen) arent rated by "S", but rather turns or kV, LiPo batteries are rated by "S" though. I want to know what kind of RC car is using what you've listed.
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Old 10-14-2013, 11:06 AM   #5
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i am using this for an amphibious vehicle the large leopard motor is driving the impeller and the two smaller motors are driving treads with differential steering. My question is how to best setup the two smaller motors. Should i connect them to the 6s terminals on the battery or the 12s. 12s would be preferable.
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Old 10-14-2013, 11:12 AM   #6
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and the battery ratings that i listed are based upon the max voltage expressed by each of the motor manufacturers.
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Old 10-14-2013, 12:47 PM   #7
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and the battery ratings that i listed are based upon the max voltage expressed by each of the motor manufacturers.
They dont have to be run at voltage that high.
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Old 10-14-2013, 01:51 PM   #8
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Quote:
Originally Posted by jastew1011 View Post
i am using this for an amphibious vehicle the large leopard motor is driving the impeller and the two smaller motors are driving treads with differential steering. My question is how to best setup the two smaller motors. Should i connect them to the 6s terminals on the battery or the 12s. 12s would be preferable.
OK, this is good info but leads into a bunch more questions.

I am no expert in the type of system you are looking for. Seems like it is the same steering used on a tank? I do know you can't get any differential steering if you wire the two motors in series or parallel. They need to be wired with an ESC (or set of ESC's) and "mixed".
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Old 10-14-2013, 02:39 PM   #9
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so i do have them wire with the esc's. I'm just wondering if it is possible to use those motors that have a max voltage less than the voltage of the battery.
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Old 10-14-2013, 02:39 PM   #10
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and the two smaller motors are used for the land drive train and yes it is the same steering as on a tank
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Old 10-14-2013, 04:21 PM   #11
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so i do have them wire with the esc's. I'm just wondering if it is possible to use those motors that have a max voltage less than the voltage of the battery.
Is this a vehicle you are designing yourself, or a commercial product? Ask the vendor/manufacturer.

to simply answer your questions:
yes, the motor needs to be wired with the ESC.
How this is done depends upon many factors such as what receiver you are using, and how it handles the mixing for steering, etc.

It is typically a bad idea to use a voltage higher than the rated voltage of a motor. It can be done (to a point) with the largest factors being the potential for the motor to overheat and if the ESC was designed for the higher voltage input.
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Last edited by 240Z; 10-14-2013 at 04:31 PM.
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Old 10-14-2013, 05:05 PM   #12
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It is typically a bad idea to use a voltage higher than the rated voltage of a motor. It can be done (to a point) with the largest factors being the potential for the motor to overheat and if the ESC was designed for the higher voltage input.
Also, the motor might not be able to physically handle the higher rpms that higher voltage setups can dish out. while the probability is low, you could potentially get into blown rotors. (though this is more of an issue on 1/10 540 and 550 sized motors.)
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Old 10-14-2013, 05:52 PM   #13
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thanks for all your help. Will reducing the throttle for the remote connected to the esc reduce the voltage below the max voltage for the motor?
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