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:
- 2300KV version – Gearbest.com
- 2600KV version – EmaxModel.com
They are often called “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.
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 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.
I am testing the motors with the following setup:
- ESC: KISS 24A Race Edition – Factory Settings
- Battery: Turnigy Nanotech 4S 1800mAh
- Voltage: 16.2V – 16.6V
- Turnigy Thrust Stand
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.
| 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.
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.
85 comments
Hi Oscar. I have 3000mah 11.1 3s battery ,RS2300KV motor .how much current drawing Please explain
Hi Oscar, Thank you for your work, I come to your page many times to get info.
I would like your advice on a problem with my setup: RS2205, 2300, Holybro Kakute F4 v2, TekkoS 4-in-1. The motors spin when I arm, but make a horrible sound. I tried changing the ESC timing to high, demag to high. No change. I added a 1000uF capacitor to the battery leads, the screeching stopped. Now I added the Vtx and camera to the board and the screeching is back. How can I solve this? With a larger capacitor? Anything else I could try?
Please could you post your question on our forum (intofpv.com)? It’s easier for us to help on that platform as i don’t check comment very often.
Hi Oscar,
I have purchased RS2205 2300KV motors with BLHeli 20A ESCs and HQ6045 props. I am using “F450 Hot Wheels DIY quadcopter frame F450 rack integrated PCB board DIY drone” as my quad frame and using 4S 14.8V 4500mAh battery. I would like to know if the items that I have purchased help me to make the quad fly. Weight of my quad will not exceed 1Kg.
Kindly review this.
Thanks in advance.
Best Regards,
Shrikant
I just got These well the 2205s 2600kv and they are not hard to spin but are really sticky to turn. Almost like there is a notch system in there. Anyone else have this? And is it normal.
Hello Oscar,
Going crazy, have multpile 3s setups but latest build is red bottoms and 30a opti escs 4s, can’t get off ground due to terrible oscillations.
Cc3d, libre pilot. Have recalibrate escs and redone set wizard with no success.
Thank you for all help!
Hi, I had the same issue on a similar build, huge oscillations and accelerating crazy alone as soon as off the ground.
What I did is doing the wizard of librepilot and choose current tuning on the initial tuning frame, so no pre-configuration, then go put my pid very low : p at 10 or 12 in basic mode, like divided by 3 or so from default values.
Hoping it may help, before that I really thought I had a defective esc or accelerometer or blew up something during mounting process
Thanks Oscar, you helped me make a decision on how to go.
4 more ES2205S-2300s to your credit. Probably at least one set of 2600KVs not far down the road.
This from a guy with green motors on all his “good stuff”!! And snake decals on his boxes… Emax needs a cool Red dragon decal or something…
Hope Emax takes care of you!
Scott
Hi oscar,
What should i buy?All 4 CCW MOTORS or ALL 4CW motors or 2 CW and 2CCW motors?What is the difference between them?
basically just the motor shaft thread direction: https://oscarliang.com/propeller-shaft-adapter-nuts-cw-ccw/
I personally prefer motor all the same rotation so if i needed replacement prop nut I only need the standard ones (rotate clock wise to fasten)
If you want them to rotate clockwise to tighten which is the correct buy then. Cw or CCW. I currently have the vortex pro and prefer them all to be like that as I have many prop nuts for it.
Hi oscar i m from india and i want to build my first drone but there is not satisfactory rc stores so how to get the best parts in cheap price?
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!
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.
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.
it’s better to use 2600KV or higher for 4′ props, i think 1806 motors would do fine. definitely use 4S.
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
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
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?
I probably wouldn’t use 2205 motors on 180 quads… get some 1806 instead!
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.
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.
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?
They are rated for 4S max, I wouldn’t recommend running them on 5S :)
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.
“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.”
What C rating should the battery have with 4x 20A ESC and 1600kV Motor?
2600kV motors I mean
I use 1500mah 50C 4S
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
Not the best ESC’s, but they should work fine for beginner.
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!!!
can some one show me how to wire up esc to rs2300motors cw and ccw ???
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.
hi, I just bought rs 2205-2600kv, and kiss 24a with kiss fc, will the 24a esc be ok running 5045 tris?
thanks
maybe a bit too much, this combo draws well over 30A… 5045 is pretty much the limit
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) ?
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!
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 ?
yes 20A ESC should work, but make sure your propeller choice doesn’t draw too much current.
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!
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…
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.
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.
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.
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
Thanks for your reply Oscar. I bit the bullet and got some 4S batteries to go with the shiny new motors
Hi Oscar,
Thanks for the wonderful review. Do you know what the downside is to running all CW or all CCW motors?
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.
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.
thanks for letting me know. I didn’t have this problem probably because i am on 4mm arms with washer…
I can confirm this, just killed 2 motors because of this :(
V
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
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..
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?
nope, no typo, it’s confirmed with 2 different motors, 3 different ESC’s… Gemfan bullnose just runs more efficiently.
Hi Oscar
Do I see it right? We don’t get nuts for the motors?
you mean prop nuts? they do come with 3 prop nuts per motor.
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 :)
yea that’s an unauthorised copy of my work, shame on them!
And as far as the first point goes?
Hi Oscar,
You should really follow up on that unauthorised copy of your work. People copying your hard work and making it look like their own is absolutely disgraceful and sites doing that in the hope of gaining advertising revenue should really be shut down. Good luck with it.
is it possible to use the 2600kv motors with littlebee’s 20A ESC’s?
yea you can.
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…
that’s an interesting comment, I am not familiar with magnets guess i need to read up on it. :)
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 ;)
Do you have a link?
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).
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.
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 :)
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.
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?
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…
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….
Hi oscar
Any Chance you could do a prop test of the dal 4045 tri blades on the 2600kv edition.
Would be highly appreciated ??
Would you test the 2300kv with 3s and 6inch props?
yes when i have a chance, i forgot this time
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,
26 or 28 AWG would be fine!
Hi Oscar, Thanks for the good review. Which motors would you recommend to someone who wants a lighter 5″ setup?
RCX 2205 2350kv are very light.
probably the 2300kv version with either 5″ triblades props, or bullnose
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.
2600kv for 3S lipo
lighter config