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Sabertooth resistors

Discussion in 'Motor actuators and drivers' started by joel043, Jun 1, 2018.

  1. joel043

    joel043 New Member

    Jan 16, 2018
    Automotive Engineering student
    Maastricht, The Netherlands
    +0 / 0 / -0
    Hi everyone,

    I am in the process of creating an electrical schematic for my simulator and something seemed quite odd.
    I have purchased a sabertooth 2x32, which has 2 included power resistors (5,1 Ohm & 10W each).
    When using the calculator on their website, it says that I should use 3 Ohm resistors for each channel, with a whopping 192W. I am using 24V motors. Since these are way bigger and more epensive than the inluded ones, is it advised to just buy the more expensive resistors, or should I be fine with one 5,1 Ohm 10W resistor per channel? Using a battery to absorb the regenerative current is not an option.
    I have seen some people use the resistors, but this huge difference between the value they advise on their site got me wondering..

    Thanks in advance,

  2. Ads Master

    Ads Master

    +0 / 0 / -0
  3. BlazinH

    BlazinH Well-Known Member

    Oct 19, 2013
    Oklahoma City, USA
    +1,833 / 32 / -1
    If your input values were correct then their calculator gave you the resistor value they recommend. But you can always try what you have already. Worst case is you will get a smoking or possibly burning resistor. Therefore maybe have a fire extinguisher handy if you give it a go.
    • Like Like x 1
    Last edited: Jun 1, 2018
  4. Trigen

    Trigen Active Member

    Nov 25, 2018
    +138 / 0 / -0
    My Motion Simulator:
    2DOF, 3DOF, DC motor, Arduino
    Old post but i've been looking a bit on this myself. I didnt buy any resistors when i got the sabertooth 2x32 as i had no clue what my wiper motors were in wattage or in power output. On a side note this is a G seat and i have about 10-14 amp max draw on the motors under my butt. When i measure both of these combined from the actual P1-P2 channel on the sabertooth i get a spike of about 0.4 amps and 0.2-0.3 average which gives me a result of 30hms at 4.8 watts so just divided that and went for some 40 ohm resistors to be a little on the safe side as i saw some very rare spikes of 0.3 on a single channel. Its in the ballpark anyhow

    As i'm not an electrician in any way i'm not sure this is correct but it makes a lot more sense than the expensive 2 ohm and so on. It does not say specific what kind of braking forces we are talking about in the manual but i'm leaning more towards cars and things of that nature.

    What do you guys think?