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Good quality 20a brushless ESC

CrazyFastFlying

Well-known member
#1
Hi guys,

I'm just wondering where everyone get's ESC's. The BLHeli one I got from eBay didn't work right out of the box.

I'm looking for a cheap but pretty good quality ESC.

Thank you!
 

kdobson83

Well-known member
#3
Hi guys,

I'm just wondering where everyone get's ESC's. The BLHeli one I got from eBay didn't work right out of the box.

I'm looking for a cheap but pretty good quality ESC.

Thank you!
I use these from banggood.com and they work great.
[US$12.60]FMS Predator 30A Brushless ESC With 2A Linear BEC XT60 Plug for RC Models RC Parts from Toys Hobbies and Robot on banggood.com
https://banggood.app.link/s6MJpFS3pW
They have 20a available too. Ships from China or California depending on the warehouse you choose. They have lots of other brands too including the emax brand which I use more often. Haven't had trouble out of my emax esc's yet.

What problem are you having?
 

FDS

Well-known member
#5
Yes, the 30A ESC’s go in the fuselage fine. Currently I am using all Hobbywing Skywalker ESC’s in my builds, since my other supplier has been out of stock for ever.
 

Arcfyre

Well-known member
#6
I get the 4 pack of cheapo ESCs on Amazon. It's $25 for 4 speed controllers, hard to best that price.

If I need something with more juice, I'll usually get the red brick brand from hobbyking. Cheap and they do what I need them to do.
 

bigron3

Junior Member
#10
I get my esc’s from Heads Up RC. I try to get the Sky Power line so I only need one programmer for all my Esc’s. I only buy esc’s with Switch-mode bec’s. I have never had an esc issue with Sky Power brand. They have a wide range powers so one always seems to fit my needs. Heads Up RC is a good place to do business with also.
 

skymaster

Well-known member
#11
careful if you buy the combo's from ebay, i bought two with the yellow esc's and both esc's shorted out. one of them got the motor super hot.
luckily the motor was not damage tried it with another esc and it worked flawless .
 

Bricks

Well-known member
#13
Yes, the 30A ESC’s go in the fuselage fine. Currently I am using all Hobbywing Skywalker ESC’s in my builds, since my other supplier has been out of stock for ever.

I have a couple of the Skywalker brand and they have held up well compared to some of the HobbyKing branded ESC`s

I
 
#14
careful if you buy the combo's from ebay, i bought two with the yellow esc's and both esc's shorted out. one of them got the motor super hot.
luckily the motor was not damage tried it with another esc and it worked flawless .
Yeah, I learned the hard way that those combos are junk as well. The motor and ESC are both horrible. If the prop saver and props fit other planes, it might have made me feel a little better about the whole thing, but no, those don't fit anything else either lol.
 
#15
Be careful following previous advice of getting a bigger esc because it can be a false economy when it burns out. Escs are designed to be run at 95% ish power. If you get for example a 30a one when you only need a 20a one the 30a one will burn out being run on 2/3rds power all the time.
If you need a 20a esc you get a 20a esc.
From my understanding, that's not how power works. It's actually backwards of how power works. It's not like a mechanical engine where if you're basically slugging along at barely any throttle, that could damage components meant to run at higher speeds. Doesn't really work that way with electronic components. I could be wrong though.
 

FDS

Well-known member
#16
My 2c- I have usually run 20A Skywalker ESC’s on Minis instead of 12A, I have several with over 50 hrs flight time, still work perfectly.
On my larger planes I typically have a 30A or 40A esc for a 25-30A load, again in 6 months of occasional flying, none has burned out.
Personally I will keep going with +20% headroom on peak load and the largest Bec I can find as I don’t want a baking hot ESC or brownout.
Everyone has different approaches to this stuff, let’s respect that and not get bogged down in a back and forth? So far there’s several UK posters in this thread, we should set a high standard for mutual respect. My opinion on keeping a proper stiff upper lip.
 

Chuppster

Well-known member
#17
I don't care enough to explain it to you after your abrasive reply.

You wasn't sure hence your reply of 'unless I'm wrong' I'm saying yes you're wrong.

You want to make an issue out of it you go for it but you'll be on your own.

I suggest you do some much needed research.
If you don't care enough to explain it, it sounds an awful lot like you don't know what you're talking about.

When you made the statement that ESC's are made to work at 95% capacity most of the time, is that based on the fact that higher frequency switching leads to more heat generation? Last I checked our ESC's are fixed-frequency PWM, so that would be a fallacy. I could understand an argument for 100% throttle being the most efficient (due to no PWM switching), but it would seem to me that the RDSon of the fets would still be the determining factor in terms of heat output rather than the sub-gigahertz switching frequency of the PWM. If that is the case higher throttle means more stress on the ESC. Even then, it has nothing to do with power rating and everything to do with throttle setting. Am I missing something? Please enlighten me!
 

Chuppster

Well-known member
#18
E
Be careful following previous advice of getting a bigger esc because it can be a false economy when it burns out. Escs are designed to be run at 95% ish power. If you get for example a 30a one when you only need a 20a one the 30a one will burn out being run on 2/3rds power all the time.
If you need a 20a esc you get a 20a esc.
At no point did I talk about efficiency. I was referring to the comment above. Your claim that ESC is "designed" to run at it's rated capacity is not factual. Please do not spread falsehoods when answering peoples questions, it's unproductive and maybe even harmful. He could put a 60a esc on his 10a motor and it'll run all day just fine. Getting a 30a esc is a fine solution to his question, provided the materials are quality. I have not used the cheap "yellow wrapped" Chinese ESC's because I don't trust the quality of the materials.

If you want to talk about efficiency (power in vs power out), an ESC will theoretically be most efficient at 100% throttle due to the absence of PWM switching for throttle control. However, a higher rated ESC *should* have fets with a lower RDSon to handle the higher current, which would lead to a more efficient ESC. In reality the power losses we see through an ESC are fairly small (compared to mechanical inefficiency, as you mentioned).
 

Chuppster

Well-known member
#19
Perhaps you should have quoted the comment you was referring to in order to avoid confusion.

As you didn't answer my question I shall answer it for you.
No, a motor is not 100% efficient throughout it's rev range and as such has a power curve.
That power curve has a a peak and at that peak it is it's most efficient. When a motor is running at it's peak it is putting the least amount of strain on the electronics involved.
To get the most out of a power system it is advantageous to have an esc that runs that motor at it's peak.
My statement of an esc being designed to run at around 92/95% refers to designers taking a very educated guess that on average a motors peak is around the 92/95% mark so at full power the motor is running at it's peak.

When a power system is not running at it's peak it generates heat and heat causes more inefficiency. Of course a bigger esc than needed is perfectly fine and will run all day but the motor might not ever be run at it's peak performance and your batteries might not be getting every last second on run time otherwise possible.

Obviously there's other factors like no load current when doing a dive for example but it's hardly a prolonged state.

Let me be clear here I'm not pretending to be be any expert on this I'm merely regurgitating others hard work much the same as others are.
I'm going off a thread on either rcgroups or runryder where a lot of testing with a trex was done and various motor and speed controls tested. The results being try to match your esc to your motor and really cells for that matter, as best you can in order to get best performance from them.


Having reread the post you've quoted I stand by my statement of saying be careful on your selection because i beleive yiu should be careful selecting your powrr train however I did not quite realise I had said it WILL burn out, that was the wrong thing to suggest and I do in fact take that back.

To be accused of spreading falsehoods and possibly causing a lot of harm by doing so is just preposterous, you might visit a forum to cause an argument but I visit to try and help people whilst getting bits of help myself. I post what I believe is right just like everyone else on the forum. Sometimes things may not be worded perfectly all the time by me or anyone else but the intention of trying to help is still there so I find the insinuation that I'm intentionally trying to derail people and maliously posting incorrect information extremely offensive.
I may have over-exaggerated the consequences of being wrong here. It is just a hobby. However, I am going to argue that if you are wording things incorrectly it doesn't matter what you know or don't know, what matters is how the reader interprets it. From my end it looked a lot like you were talking about things that, according to what I've learned in EE, make no sense. Additionally, I never "insinuated" that you were "intentionally trying to derail people". Actually I believed the best in you, that you simply were doing it by mistake. It happens to the best of us.

There are a lot of great people on forums doing great work to test motors, and it's true that motors have an efficiency curve, but ESC's have little to do with choosing an efficient prop/battery setup as long as it can handle the current and the voltage/cell count. To be honest, I'm not sure what you mean when you say "My statement of an esc being designed to run at around 92/95% refers to designers taking a very educated guess that on average a motors peak is around the 92/95% mark so at full power the motor is running at it's peak." I'm not sure if you are trying to say the ESC needs to run at 95% of the ESC's peak current handling (a very wrong statement) or the motor should run around 95% of it's peak efficiency (I can see an argument for this one). He asked about an ESC's current rating and you gave what I would consider to be bad advice based on an auxiliary factor (motor efficiency). That's why I called you out.
 

Chuppster

Well-known member
#20
I was saying that a motor has a very small peak performance which drops off after that peak.

If I'm allowed to just make some numbers up to make my point I'll say for example a 20amp esc running a 20amp motor will put 92% to the motor when the esc is run at full power because it's been guessed that's where the power peak is on average. So at full power the esc is powering the motor very close to it's optimum operating conditions.

A 30amp esc running a 20 amp motor will give the motor 100% on full power which pushes the motor over it's peak performance.
The motor is screaming away at full power but not running at it's most potential.

Of course it will run all day over it's power band, the motor will get warmer than it needs to and the batteries won't last as long as they could do but I admit the differences can be slight, there are also those of us who simply don't fly everywhere at full power anyway so the point is mute. It's only an average of 8% on full power afterall.

I only mentioned efficiency once talking to you to explain my point, it was not mentioned in my initial post.

I could have explained it better earlier on if the initial responce wasnt so unfriendly and then when you waded in with a rather quite agressive string of replies it becomes more difficult to keep coming back to the thread.

Hopefully this is now quashed, you seem to get my point now and somewhat seem agreeable to it.

I might be starting to understand where you are going. However, I don't think you are correct because I think you are making an assumption. Let's lay out the setup here:

Motor, rated at 20 amps
ESC, rated at 20 amps
3 - cell battery capable of delivering 20 amps

If you choose a propeller that draws 20 amps from the motor, you should be okay (although a little overhead is good). If you choose a larger prop and draw, say, 30 amps, you are going to burn things up unless you exercise extreme throttle control. It sound to me like you are making the assumption that a 20a ESC will only deliver 20 amps. That is incorrect. If you short it it'll deliver hundreds of amps and burn up in a second.