EMAX RS2205 2300KV & 2600KV Motors – Cooling Red Bottom

The EMAX RS2205 motors are awesome! From my thrust result they completely destroyed the Cobra motor.

To support more testing like this, please get your EMAX RS2205 Motors from these vendors:

They are often referred to as “red bottom” because of the red motor base they have. Both motors weight nearly the same around 30g, and look identical from the outside.

They are about 5g heavier than the Cobra 2204, because there is more metal used on the base and the bell, and it looks a bit bigger from the picture. In fact they are both 2205 motors (05 being the height of the motor stator), although Cobra preferred to call them 2204.

I was told by EMAX that they used some different magnets on these motors (N52), and the new design includes “cooling fins” which keep the coil temperature down by at least 30%. I have no way to verify this with the gear I have, however I could try to feel it with my poor fingers after each run hehe :D

These motors have CW and CCW thread rotations (optional on product page). The motor wires are 20AWG.

emax rs2205 2300kv 2600kv motor cobra 2204 comparison

Unboxing

EMAX does a very good job in the packaging. And it comes with 8 motor screws, 3 props nylon nuts and a hex key.

emax rs2205 2300kv 2600kv motor box package emax rs2205 2300kv 2600kv motor parts includes unboxing emax rs2205 2300kv 2600kv motor include screws bolts driver

EMAX RS2205 2300KV Motor

The performance of this motor blew me away! Comparing to the popular Cobra 2204 2300KV motor, the EMAX Red Bottom shows better efficiency as well as generate more thrust than the Cobra (in most cases) in my tests.

emax rs2205 2300kv motor review

I am testing the motors with the following setup:

emax rs2205 2300kv 2600kv motor propeller thrust test

EMAX RS2205 2300KV Motor Thrust Data

Props % Peak Thrust – g Peak Current – A Max Power – W Efficiency – g/W
Gemfan 4045 50 148 2.3 37.3 3.97
  100 460 9.6 155.5 2.96
HQ 4045 BN 50 257 4.4 71.3 3.61
  100 647 19.3 312.7 2.07
Gemfan 5030 50 295 3.2 51.8 5.69
  100 790 15.0 243.0 3.25
Gemfan 5040 50 304 3.9 63.2 4.81
  100 880 17.8 287.9 3.06
Gemfan 5045 50 342 4.6 74.5 4.59
  100 938 21.6 349.9 2.68
Gemfan 5045 BN 50 395 5.0 81.0 4.88
  100 917 23.3 377.5 2.43
HQ 5045 BN 50 386 6.3 102.1 3.78
  100 989 28.6 463.3 2.13
HQ 5040×3 Triblade 50 411 5.3 85.9 4.79
  100 1050 25.0 405.0 2.59
Gemfan 5045×3 Triblade 50 417 5.4 87.5 4.77
  100 1155 27.3 442.3 2.61

The Gemfan 5045 Triblades prop were from BG $3.5 for 4.

Cobra 2204 2300KV Motor Thrust Data

I previously tested this motor, but it was with a Blue Series 20A ESC with BLHeli firmware. The data was a bit on the low side because of the ESC just wasn’t good enough, so I have re-run the same test with the KISS 24A ESC.

Props % Peak Thrust – g Peak Current – A Max Power – W Efficiency – g/W
Gemfan 4045 50 133 2.0 32.4 4.10
  100 429 8.9 144.2 2.98
HQ 4045 BN 50 235 4.3 69.0 3.41
  100 588 18.2 294.8 1.99
Gemfan 5030 50 265 3.1 50.2 5.28
  100 718 14.3 231.7 3.10
Gemfan 5040 50 296 3.5 56.7 5.22
  100 810 16.8 272.2 2.98
Gemfan 5045 50 315 4.4 71.3 4.42
  100 837 19.7 319.1 2.62
Gemfan 5045 BN 50 375 4.7 76.1 4.93
  100 865 21.0 340.2 2.54
HQ 5045 BN 50 369 6.4 103.7 3.56
  100 862 27.2 440.6 1.96
HQ 5040×3 Triblade 50 355 5.0 81.0 4.38
  100 875 22.1 358.0 2.44
Gemfan 5045 Tri 50 401 5.2 84.2 4.76
  100 947 24.4 395.3 2.40

EMAX RS2205 2600KV Motor

The 2600KV version is probably designed for 4″ props on a 180 mini quad. However I do find it perform reasonably well with 5030 props, so I might try that setup on my next 5″ build.

It can be also a good performer on 3S LiPo with 5″ props I think, unfortunately I forgot to test it on 3S! Oh well I will update the result when I have a chance.

With any props bigger than 5045 current draw just went over 30A which is no good for the 24A ESC I was using for testing hehe.

emax rs2205 2600kv motor review

Props % Peak Thrust – g Peak Current – A Max Power – W Efficiency – g/W
Gemfan 4045 50 189 3.4 55.1 3.43
  100 529 13.5 218.7 2.42
HQ 4045 BN 50 311 6.4 103.7 3.00
  100 776 27.0 437.4 1.77
Gemfan 5030 50 355 4.7 76.1 4.66
  100 990 21.7 351.5 2.82
Gemfan 5040 50 395 5.3 85.9 4.60
  100 1025 25.6 414.7 2.47
Gemfan 5045 50 430 6.2 100.4 4.28
  **100 1120 30.0 486.0 2.30
Gemfan 5045 BN 50 400 5.8 94.0 4.26
  **100 1074 30.0 486.0 2.21
HQ 5045 BN 50 496 9.2 149.0 3.33
  **100 915 27.0 437.4 2.09
HQ 5040×3 Triblade 50 435 7.0 113.4 3.84
  **100 1025 29.0 469.8 2.18

** ESC entered over-current protection at 30A before 100% throttle was reached, so that might not the true full throttle thrust.

emax rs2205 2300kv 2600kv motor side by side

Conclusion

I think the RS2205 is probably one of the best motors currently for 5″ props. But someone who want the lightest setup might find it a bit heavy at 30g each.

It’s also interesting to note that during the tests with bullnose props, the Cobra motor felt significantly warmer than the RS2205, which means the cooling fins are working.

72 thoughts on “EMAX RS2205 2300KV & 2600KV Motors – Cooling Red Bottom

  1. Adney

    Hey Oscar! Big ups to you. Your guides helped a lot. Also I am not sure if you will reply, but still giving it a shot.
    I have the emax rs2205 2300KV, i want to run it with a 3S battery, but i don’t know what C rating i need to use, also not getting the thrust amp data for these motors on a 3S setup, so can’t really decide. Much help appreciated!
    Awaiting your reply.

    Thank you!

    Reply
  2. Javi

    Great stuff. Would love to see prop weight in grams included in the data. Maybe grab a set of 4 and divide by 4 to get a solid average. I have a little jewelry scale that measures in to the hundredth. Nifty.

    Reply
  3. Greg

    Hi Oscar

    So which combo will you suggest for Tweaker 180 ? 1806 2280KV and 20A ESC or 2205 1600KV and 30A? 3S as start then 4S later on.

    Reply
    1. Oscar Post author

      it’s better to use 2600KV or higher for 4′ props, i think 1806 motors would do fine. definitely use 4S.

      Reply
  4. Rob

    Hi Im going to be building a Secret Weapon SW5 and Going for Kiss FC, Kiss 24a ESCs and the 2205/2300kv but im having a hard time trying to figure out which moto is which I want normal threaded nuts not reversed. the way they list it on the site i confusing can you please shed some light please. do I want CCW Thread/ CW Rotation or CW Thread/ CCW Rotation.

    thanks

    Reply
    1. Shubhankar Das

      U need both cw n ccw …2 pairs…as multirotor have alternate motors running at different direction so emax made cw nd ccw threaded motors so that the nuts doesnt loosen on rotation..ccw threaded must be cw rotating n vice versa

      Reply
  5. Thomas Huster

    Hi Oscar,

    Great review, your reviews are always a great place to get updated on the best stuff.
    What would you recomend using with 2600kv, epiQuad 180 and 4×4.5*****Props?

    FVT Littlebee_S 30A Or FVT Littlebee Pro 20A?

    Reply
  6. Darren

    Can you tel me if cutting the motor wires shorter on the Emax motors will have any negative effects with the motor’s winding’s. I have heard some motor wires you can cut others you will destroy the motor.

    Reply
  7. emanuele

    Hi Oscar,
    very nice review that was very useful.
    I got four of these motors, but three out of them apparently dont work :(
    They simply dont start. They stutter a bit when I increase throttle, then stop with a beep. I get another beep when I zero the throttle. That’s it.
    The only thing was that I used the screws provided with the motors, then I read that the screws are too long for a 3 mm arm, as mine is, so I used some spacer to avoid shorts before to switch them on. I’m wondering of could have damaged the wires on the stator.

    Reply
  8. Ole-Petter Rong

    Hi.

    Wondering how these motors would run at 5s 18.5v?

    Currently wondering to buy rs2205 2300kv, littlebee 30a and DALprop V2 T5045 Bullnose Prop

    Thoughts?

    Reply
  9. Lux Siva

    Im trying to decide on if i should get the 2300kv or 2600kv. Planning to running 4s on a qav210 with 5 inch props. Which one would you recommended.

    Reply
    1. John

      “The 2600KV version is probably designed for 4″ props on a 180 mini quad. However I do find it perform reasonably well with 5030 props, so I might try that setup on my next 5″ build.”

      Reply
  10. Shubhankar

    hello oscar
    i am having those 2300 kv rs2205 ….can i use them with emax 20amp simonk esc if size is not the issue…n for begiener fpv flying….will this setup do the beginer job

    Reply
    1. shane lucas

      i used them with my littlebee pro opto 20 amps, and they worked great!!!!. I know have them on my 210 r speed addict with littlebee 30amps, and they SCREAM!!!

      Reply
    1. Rob

      Doesn’t matter how you wire it…just solder it and set it up in CleanFlight and BLHelisuite…you can reverse motor direction in BLHelisuite.

      Reply
  11. Ronan

    hi, I just bought rs 2205-2600kv, and kiss 24a with kiss fc, will the 24a esc be ok running 5045 tris?

    thanks

    Reply
  12. Ronku

    ESC entered over-current protection at 30A before 100% throttle was reached, so that might not the true full throttle thrust.

    ☝️ so 30 A should be fine for both (2300 KV & 2600kv) ?

    Reply
    1. Oscar Post author

      yes should be fine as long as you don’t over-prop your motor :)
      I am using 2600KV on 4S, with 5045/5040 props works great!

      Reply
  13. Théo

    Hello Oscar !
    Thank you for this very great review of these motors !
    Just one question : does this motors fit with 20A esc from LittleBee or Emax ?

    Reply
  14. Daniel Gauci

    Hi Oscar, I currently run a Goby 210 with Dal 5045BN propellers. I was thinking about upgrading my RCX H1806 motors to the RS2205 however I’m not sure whether I should get the 2300kv or the 2600kv ones. Is there a big difference between the two in real life in performance? And do the 2600kv motors drain the battery much faster than the 2300kv ones?

    Thanks!

    Reply
    1. Oscar Post author

      As you can see in the thrust data, at full throttle, the higher KV motor with lower pitch props gives more thrust and use less current than 2300KV with higher pitch props… so I would probably go for the 2600KV motor…
      That’s what I am using now, the high RPM really helps in racing as well as it accelerates really quick, you can see the difference in bank turns…

      however I find the 2300KV motors are easier to get a clean tune… i am still struggling to get rid of oscillations on the 2600KV…

      Reply
  15. James

    How would the 2600kv version do against the 2300kv on a miniquad running the TBS Powercube? Which would you recommend for ultimate performance running either HQ 5040 TRI or HQ 5045 BN.

    Reply
    1. Oscar Post author

      i don’t have the powercube so not sure how good it is.. but I would run 2300kv for 5″ triblades or bullnose just for the safe side.

      Reply
  16. Simon

    Hi Oscar,

    Nice review. I just bought the 2300kv for my 3S build, should I have bought the 2600kv model?
    I cannot find any 3S thrust data, maybe 3S is going out of style?

    Cheers,
    Simon.

    Reply
    1. Oscar Post author

      2300KV on 3S should be fine. 4S, 3S it’s all personal preference, but a lot of people prefer the power and punch on 4S

      Reply
      1. Simon

        Thanks for your reply Oscar. I bit the bullet and got some 4S batteries to go with the shiny new motors

  17. Julich Mera

    Hi Oscar,

    Thanks for the wonderful review. Do you know what the downside is to running all CW or all CCW motors?

    Reply
    1. Simon

      Hi Julich,
      The difference between CW and CCW motors is the thread direction of the propeller mount. So the only downside is that if you don’t screw your props on tight, they may come loose.

      Reply
  18. Gunnar

    Hi Oscar, thanks for your great review. Just received mine and there is a problem, which you should mention in the above text. The supplied screws are to long. I received 7 to 8mm long screws with the motor. With my 3mm arms, the screws seem to touch the winding -which can not be seen from the outside – causing a shortcut and massive overheating. The screws should only reach 3mm into the motor. With my 3mm arms, 6mm screws are just fine, 7mm ones will cause massive heat. I read somewhere that emax has changed that and now supplies 6mm screws with the Motors, so please meassure your screws before mounting.

    Reply
    1. Oscar Post author

      thanks for letting me know. I didn’t have this problem probably because i am on 4mm arms with washer…

      Reply
  19. Lars

    Hi,
    thanks for the good review
    i want to build a 180 quad with a 4in1 ESC with 22A
    and my plan is the Emax 2205 2600kv with
    4×4.5 BN or Triblade BN with 4×4.5 from Gemfan
    you think it’s possible or is the 22A ESC to small?

    Thanks

    Reply
    1. Oscar Post author

      not perfectly safe, but again in real flight you can’t hardly reach 100% throttle on your ESC/motor due to how the PID algorithm works… it’s risk you have to take if you want to go that route… maybe get the XM30A if you want some more safety, they are good as well..

      Reply
  20. Dawid

    How come there’s over 6A diffrence on 100% power between HQ and GF 5045BN props? That’s insane diffrence. You sure there was no typo there?

    Reply
    1. Oscar Post author

      nope, no typo, it’s confirmed with 2 different motors, 3 different ESC’s… Gemfan bullnose just runs more efficiently.

      Reply
  21. jrsall92

    Hi there, two points:

    1) Correct me if it has been mentioned and I didn’t see it but could you please check the 2600kV on 5045×3 with a bigger ESC? just curious to what the thrust and current will be.

    2) I also found this droneuplift.com/emax-rs2205-2300kv-2600kv-motors-cooling-red-bottom/ and it seems awfully similar to this article with the exception that there isn’t your info in the bottom of the images. Don’t know if it’s you on the other article too, just wanted to let you know :)

    Reply
  22. Arne Petry

    Hi Oscar,

    something that should be mentioned in a review of those motors, is that emax sacrificed durability for short term power:
    The reason for that is, that N52 magnets are only temperature resistant up until 80°C; in reality this means that they start to loose magnetic power when they get over 60°C which will be quickly reached in a race.
    Other manufacturers use “M” or “H” classified neodym magnets which will endure 20°C or 40°C more.

    The “improved” cooling is supposed to counter this of course, but personally I have my doubts about that.
    So Oscar please fly them hard for a couple of weeks and then test again!
    Hopefully I am wrong – then I will immediately place my order…

    Reply
    1. sam

      The motor’s active cooling reduces heat soak by 30% compared to other motors with similar load and testing conditions. HPIGuy on youtube does an infrared test on one of the emax motors (mt2205 cooling but similar bell design on rs2205) to see if the cooling works. You should check that out ;)

      Reply
    2. nin2thevoid

      About the heat versus magnet choice: I put 2600kv’s under some Dal Bullnose triblade 4″, insane power but also insane power consumption. Can’t get enough of doing punchouts and blasting the quad across fields. The lipo (Bonka 4s 1300mAh) gets pretty hot. The motor and ESC’s, feel barely warm to the touch right after landing. Can’t be more than 35°C – 40°C.

      If this is because of air flow or because of the cooling system, I don’t know. I worry about a lot of stuff when taxing the quad like this, but motor heat just isn’t one of them. These suckers stay cool. Only when an ESC was close to dying, it (and the motor) got very hot in a short time because of bad syncing, but that has nothing to do with the motor (everything was perfect after an ESC swap).

      Reply
  23. Claudio

    Hi oscar i want to know if it’s possible .the bell on the 2600kv and the 2300kv are the same?
    I have brought 4 cw 2600kv motors am now i want to buy 4 2300kv (ccw)motors and if its possible to swipe 2 bells that way have two sets for a 210mm and 180mm size quad.

    Reply
    1. Oscar Post author

      To be honest I am not 100% sure, I think the KV difference comes from the number of wilding, but i am not sure if the magnets are different as well but i doubt it :)

      Reply
    2. sam

      The 2600kv and 2300kv motors share the same bell and magnets. The only difference is in the winding of the coil. You can interchange every part of the motor except coil.

      Reply
  24. Eric

    Hi Oscar,
    With each motor pulling 27+ amps with max thrust setups, it seems like the normal 1300mah battery won’t be able to supply that. Do you think its possible to see those kinds of figures with all 4 motors pulling at once, vs just the one in these thrust tests?

    Reply
    1. Oscar Post author

      in real flights, your motors won’t be able to draw that kind of current because of the FC will lower the output to achieve balance… besides you won’t be flying 100% throttle very often…

      Reply
  25. Hexabones

    Thanks for the bench.
    The bench tests are one thing . But I advise you to use them in flight to make you a real opinion….

    Reply
  26. Harry Stephens

    Hi oscar
    Any Chance you could do a prop test of the dal 4045 tri blades on the 2600kv edition.
    Would be highly appreciated ??

    Reply
  27. Indy

    Hi Oscar,
    Great informations…

    Yes we need more than 20A ESCs…

    Great job, I’m just missing 6 inches props test ;)

    Good to know that cable are 20awg… so maybe you could answer me helping me for an order…
    What awg would that be to replace servo cables? ESC to flight controller and flight controller it receiver?

    Thanks,

    Reply
  28. RCGuy80

    Hi Oscar, Thanks for the good review. Which motors would you recommend to someone who wants a lighter 5″ setup?

    Reply
      1. nin2thevoid

        Technically, power to weight ratio is what counts when building a quad, not the net weight. Quads are like bricks (except for the REALLY light ones) and so they all fall like bricks. Air resistance when dropping is almost negligible.
        So the question could be: which motor gives the best power to weight ratio. Emax motors really excel in that regard.

        If however you do want a very low net weight, Emax are not the way to go IMO. Not only are the motors (with half inch of wiring) still like 29-30 grams, but when you add the very heavy (2 gram) locking nut and some screws, you end up around 33 grams a piece. Cobra and RCX have significantly lighter motors and lighter locking nuts, for example. Will save you more than 20 grams on a build.

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