What amp fuse to use

Discussion in 'Electric Guns' started by randy_h, Jul 24, 2018.

  1. randy_h

    randy_h New Member

    27
    12
    Greenville
    Trying to figure out what amp fuse I should use in my gun. Is there a simple way of telling? I don't want to be starving the gun of the amps it needs, but I also don't wanna have it going too far over what it needs in case something happens
     
  2. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

    8,843
    4,910
    Minneapolis
    Replace it with what it already uses. 15-20A depending on model. You can run up to 25 with minimal issues.
     

  3. -Spitfire-

    -Spitfire- Well-Known Member

    4,417
    2,153
    Oceanside
    When I run a fuse, I usually run a 30amp, as anything less can be attributed to temporary, normal voltage spikes, and anything more will be an actual short [unless you're running a saw, dmr, dsg...]
     
  4. randy_h

    randy_h New Member

    27
    12
    Greenville
    When I got my gun it didn't have a fuse in it at all. I put a mosfet and a fuse in at the same time but I'm about to re wire my connector for a Deans and just wanted to make sure I wasn't starving the motor really. I have the MG-42 made by matrix so I imagine it's comparable to a saw/240. I have a 20 amp fuse in there now
     
  5. cetane

    cetane Well-Known Member

    937
    450
    Markham & Stouffville, Ontario, Canada
    30a... largest mini automotive size fuse you can commonly get. [​IMG]
     
  6. Lefse

    Lefse Well-Known Member Supporting Member

    6,228
    1,842
    One thing to be cautious about, the fuse rating should not be higher than the continuous discharge rating of the battery you're using or it won't fully protect the battery.
     
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  7. randy_h

    randy_h New Member

    27
    12
    Greenville
    The continuous discharge rate is C rating x amp hours right?
     
  8. Lefse

    Lefse Well-Known Member Supporting Member

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    That's correct, meaning that if the continuous discharge rating is 30A the fuse rating shouldn't exceed 30A. This is to ensure that the battery can trip the fuse before it overheats.
     
  9. randy_h

    randy_h New Member

    27
    12
    Greenville
    So really I should be more concerned with protecting the battery than the motor? If my motor needs say, 15 amps but my battery puts out 20, would a 20 fuse be fine because the motor will only take it's max rated amps?

    Sent from my SM-G965U using Airsoft Society mobile app
     
  10. Lefse

    Lefse Well-Known Member Supporting Member

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    If the battery can put out more current than the motor needs, then you choose fuse based on the current need of the motor. In both cases the fuse will protect both the motor and battery and also wiring. You choose wiring and battery that can handle more current than the motor needs, then you choose a fuse that trips slightly higher than the continuous current that the motor pulls.

    Say the motor pulls 20A cont., then you choose wiring and battery that can handle more than this and use for example a 25A fuse to get some "headroom" for startup current and such.
     
  11. randy_h

    randy_h New Member

    27
    12
    Greenville
    Sweet thanks for all the help I'm just trying to learn as much as I can to keep everything in my gun healthy
     
    Lefse likes this.