ESC / Motor mismatch??

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JezHall

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Hi Folks.

I am trying to install a brushless setup in a FTX Outlaw.

I have a cheap 120A ESC with a BL3650 -5200kv motor which runs for 1-2 seconds then reboots itself with the 3 beeps. It will then run again for a couple of seconds.

This is powered from a 6 cell 7.2 NIMH battery.

When lifted off the floor it will run forever.....and quite quickly......once put down it reboots itself.

The cogs are nicely meshed and all the cups are tight on the driveshafts.

Any ideas anyone????

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ESC.PNG
 
So, theres a couple things to point out here.

Thats really a 60A ESC not 120A. That being said the stock ESC was also supposedly 60A also so that may not be a big deal.

The next thing I see is that youve almost doubled the kV rating from the stock motor. That is going to have a couple of side effects. One is that motor is going to have to be geared waaaay shorter than the stock motor. Its going to get hot faster, especially with those large tires.

Running a bushless set up on a NiMH pack is going to drain that pack super fast, which is going to make that pack super hot, which is going to be detrimental to the longevity of the pack. Id look at running it on LiPo.

This leads me to your actual problem. If I had to speculate (and I do) then Id guess that either the new motor/esc combo is putting such a high demand on that NiMH pack that its bottoming out the voltage on the pack or the ESC is in LiPo mode and needs to be set to NiXX mode.

Hope this helps
 
the nimh is 90% of your rebooting issue. voltage sag
 
So, theres a couple things to point out here.

Thats really a 60A ESC not 120A. That being said the stock ESC was also supposedly 60A also so that may not be a big deal.

The next thing I see is that youve almost doubled the kV rating from the stock motor. That is going to have a couple of side effects. One is that motor is going to have to be geared waaaay shorter than the stock motor. Its going to get hot faster, especially with those large tires.

Running a bushless set up on a NiMH pack is going to drain that pack super fast, which is going to make that pack super hot, which is going to be detrimental to the longevity of the pack. Id look at running it on LiPo.

This leads me to your actual problem. If I had to speculate (and I do) then Id guess that either the new motor/esc combo is putting such a high demand on that NiMH pack that its bottoming out the voltage on the pack or the ESC is in LiPo mode and needs to be set to NiXX mode.

Hope this helps
Thanks for that.

I can get a couple of 2S Lipo’s, will they be ok?

Out of interest how do you know it’s only 60A?

Jez
 
Thanks for that.

I can get a couple of 2S Lipo’s, will they be ok?

Out of interest how do you know it’s only 60A?

Jez
Well, I can't technically prove its not 120A but I'm pretty sure its a clone of THIS old discontinued HobbyWing ESC which is a 45A ESC. Now given that it says 120A I'm speculating that the Chinesium company that made it listed its peak power instead of its RMS (continuous) rating which is always half of the peak power. Thats assuming that they did modify it in some way though. If its just a rip off copy it may only be a 45A ESC. There was a similiar looking discontinued Hobbywing Xerun ESC that was supposed to be 120A also but even back when you could buy it, it was about $75-$100USD, the clone version you can get off of Amazon even in todays economy for $16 so thats why I believe at best that ESC is a 60A or could even be a 45A. On top of all that, if you go and look up that ESC on Aliexpress you'll find listings for the same exact ESC and one will be labeled 45A, 60A, 80A, and 120A but they are the same exact ESC and they are even the same exact price. If you ask me its a 45 or 60A ESC and they just change the stickers on it in order to sell more. HEREs a link to what I'm talking about on Aliexpress. Click on the various models. Theyre all the same price. Below is a screen shot of all 4 variants of the same exact ESC with 4 different ratings.

Capture.JPG

Thats one of the reasons I really dont care for the cheap Chinesium stuff. Better to stick to name brand. That being said I realize that sometimes its whats in a persons budget at the time but my mom has a saying "Theres nothing so expensive as something cheap" and I'm a pretty firm believer in that. Hopefully I'm wrong about the ESC and maybe it actually is 120A but I doubt it


a 2S lipo will work givewn you can gear that high kV motor low enough now to damage itself or the ESC.
 
Well, I can't technically prove its not 120A but I'm pretty sure its a clone of THIS old discontinued HobbyWing ESC which is a 45A ESC. Now given that it says 120A I'm speculating that the Chinesium company that made it listed its peak power instead of its RMS (continuous) rating which is always half of the peak power. Thats assuming that they did modify it in some way though. If its just a rip off copy it may only be a 45A ESC. There was a similiar looking discontinued Hobbywing Xerun ESC that was supposed to be 120A also but even back when you could buy it, it was about $75-$100USD, the clone version you can get off of Amazon even in todays economy for $16 so thats why I believe at best that ESC is a 60A or could even be a 45A. On top of all that, if you go and look up that ESC on Aliexpress you'll find listings for the same exact ESC and one will be labeled 45A, 60A, 80A, and 120A but they are the same exact ESC and they are even the same exact price. If you ask me its a 45 or 60A ESC and they just change the stickers on it in order to sell more. HEREs a link to what I'm talking about on Aliexpress. Click on the various models. Theyre all the same price. Below is a screen shot of all 4 variants of the same exact ESC with 4 different ratings.

View attachment 155268
Thats one of the reasons I really dont care for the cheap Chinesium stuff. Better to stick to name brand. That being said I realize that sometimes its whats in a persons budget at the time but my mom has a saying "Theres nothing so expensive as something cheap" and I'm a pretty firm believer in that. Hopefully I'm wrong about the ESC and maybe it actually is 120A but I doubt it


a 2S lipo will work givewn you can gear that high kV motor low enough now to damage itself or the ESC.
No matter how strong this no name esc claim to be, I never had a good luck with them. I had at least 5, and all of them either didn't work at all, didn't work properly, or died after 3 packs.

I had good luck with with most no name brushless motors but when it comes to esc, never had any problem with branded esc, like hobbywing, castle or Traxxas. I had decent luck with hobbywing stuff.

22$ 60amp, it barely works, would not recommend, but for that price decent.

45amp, strongly recommend, works flawlessly, never used it with motors over 3500kv, waterproof, awesome.

Now, unfortunately discontinued trackstar 60a sportsman. Awesome esc, rebranded skyrc toro ts50, not waterproof, don't ask how I know

Instead of wasting money on multiple esc that don't work, I would buy hobbywing that will last forever

Screenshot_20221110-080313.png


Screenshot_20221110-080228.png


Screenshot_20221110-080537.png
 
Well, I can't technically prove its not 120A but I'm pretty sure its a clone of THIS old discontinued HobbyWing ESC which is a 45A ESC. Now given that it says 120A I'm speculating that the Chinesium company that made it listed its peak power instead of its RMS (continuous) rating which is always half of the peak power. Thats assuming that they did modify it in some way though. If its just a rip off copy it may only be a 45A ESC. There was a similiar looking discontinued Hobbywing Xerun ESC that was supposed to be 120A also but even back when you could buy it, it was about $75-$100USD, the clone version you can get off of Amazon even in todays economy for $16 so thats why I believe at best that ESC is a 60A or could even be a 45A. On top of all that, if you go and look up that ESC on Aliexpress you'll find listings for the same exact ESC and one will be labeled 45A, 60A, 80A, and 120A but they are the same exact ESC and they are even the same exact price. If you ask me its a 45 or 60A ESC and they just change the stickers on it in order to sell more. HEREs a link to what I'm talking about on Aliexpress. Click on the various models. Theyre all the same price. Below is a screen shot of all 4 variants of the same exact ESC with 4 different ratings.

View attachment 155268
Thats one of the reasons I really dont care for the cheap Chinesium stuff. Better to stick to name brand. That being said I realize that sometimes its whats in a persons budget at the time but my mom has a saying "Theres nothing so expensive as something cheap" and I'm a pretty firm believer in that. Hopefully I'm wrong about the ESC and maybe it actually is 120A but I doubt it


a 2S lipo will work givewn you can gear that high kV motor low enough now to damage itself or the ESC.
Hi,

I tried the Lipo’s. They are a lot faster when it’s on the bench but it hardly moves when it’s put down.

I have the hardened 62t spur gear and I have tried both 17t and 23t pinion gears. Should I be using different cogs?

Thanks again

Jez
 
Hi,

I tried the Lipo’s. They are a lot faster when it’s on the bench but it hardly moves when it’s put down.

I have the hardened 62t spur gear and I have tried both 17t and 23t pinion gears. Should I be using different cogs?

Thanks again

Jez
Does it stutter when its trying to move forward? If so then its cogging and you're going to have to put a smaller pinion on it. Like maybe an 11T.
 
Does it stutter when its trying to move forward? If so then its cogging and you're going to have to put a smaller pinion on it. Like maybe an 11T.
Yes. That’s exactly what it does !

I’ll get a smaller pinion. Can I keep the same spur?
 
Yes. That’s exactly what it does !

I’ll get a smaller pinion. Can I keep the same spur?
You can try it and see what happens but I have a feeling that with the kV being as high as it is youll probably end up needing the smallest pinion you can get with the biggest spur you can get. Honestly Id probably just buy a lower kV motor but play with the gearing and see if you can find a combination that doesn't cog. Once it doesn't cog then keep playing with the gearing until it doesn't overheat. If you can't get it to not overheat and youve maxed out on gearing then youll have to get a lower kV motor.
 
Will a 4000kv motor be much better?

Thanks again
 
Will a 4000kv motor be much better?

Thanks again
I don't have ftx but I just checked online, outlaw comes with 2900 kv motor. It depends what your goal is but it's probably the best to keep it under 3500. If you can gear it down super low and run 2s only, 5200 may work. I had 5200 kv motor but different brand in one of my cars and it was ok, but switched it to another, and I believe that it was not geared low enough and overheated.

It would be the best to make a short video how it behaves, so we can diagnose the issue easier. I still believe that even motor kv and gearing may not be optimal, it's the esc fault
If you have another brushless rc car that works, try to swap esc to test if behaves identical with different esc
 
Last edited:
Like the guys already said more or less, you need a lower KV motor and LiPos. 3000ish KV is what you usually find in 1/10 4WD trucks.
 
Will a 4000kv motor be much better?

Thanks again
A 4000kV while still a bit high IMO, would probably work with the right gearing if its a 4 pole motor. I'm not convinced youll be able to gear a 5200kV short enough to keep it from overheating but I dont have that kit so all I can do is make educated guesses.
 
☝️ but only if you're using the NiMH pack which I'm not sure why you would since you have 2S lipos.
 
Hobbywing's 4000KV motor that came with the Max10 SCT was unusable on 3s in my 4x4 Slash, even geared down. Too much heat, not enough oomph.
 

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