HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Sep 03, 2014, 02:49 PM
Registered User
Joined Sep 2014
8 Posts
Discussion
ONE brushless motor TWO esc's . can it be done?

So i am toying with the idea of adding fet'z to a esc to get more power through my motor when i realised that it would be esayer to simply run anouther esc in parallel to the original one

my question is will bouth of the esc read the feed back from the motor or will one cancel out the outher

i am runing of the assumption that the esc's wouldn't know the difference as that are reciving the same feed back down each channal but at half the power or strength

let me know what you think or if this has been tryed befor
either way i shall be trying it out when i can get hold of anouther one of the esc's that i use and i will post the results here for us all to see
powerball250 is offline Find More Posts by powerball250
Reply With Quote
Sign up now
to remove ads between posts
Old Sep 03, 2014, 03:19 PM
Suspended Account
Joined Jul 2014
791 Posts
I SEE SMOKE.. oh that ur 2 brushless esc going up in FLAMES.. just get a larger amp esc.. the most powerful one I know is a Quark SK3 500 amp output with 1500 amp burst for 30 seconds .. sky and technology made them.. I own 5..LOL..
ElectricMann is offline Find More Posts by ElectricMann
Reply With Quote  (Disabled)
Old Sep 03, 2014, 03:22 PM
Registered User
Joined Sep 2014
8 Posts
I could do that but i don't have that kind of cash and it would take me a very long time to get it were as 2 60a esc only bout 40 from a trend of mine
powerball250 is offline Find More Posts by powerball250
Reply With Quote
Old Sep 03, 2014, 04:22 PM
Did you check the FAQ already?
SoloProFan's Avatar
The Netherlands
Joined Jul 2010
13,674 Posts
The ESC doesn't push current through the motor, so adding another will not make your motor perform better. If you motor draws 70A, and you have 90A ESC, your car won't run faster if you get a 120A ESC. You just need to get an ESC that can deliver the current the motor needs to run, and a little more preferably, for some headroom. If your current ESC can't, it will heat up too fast and fry.

Running 2 ESC to drive one motor is doomed to fail, just imagine if one ESC makes a different guess about the rotor position, and sends current to a different pair of coils than the other.

What motor are we talking about, and how much current does it draw?
SoloProFan is offline Find More Posts by SoloProFan
Reply With Quote
Old Sep 03, 2014, 04:28 PM
Suspended Account
Joined Jul 2014
791 Posts
not even counting the back feed of one esc to the other..LOL.. add more cells go faster 2 cells 30 mph 4 cells 60 mph 6 cells smoke but fastest yet 90 mph with smoke effect..LOL



solo I have to disagree with u on the upper statement.. I have 5 esc.s from 45 amp to 250 amp.. by far the 250 amp esc is alot faster than all the lower amp esc and motor is rated at 40 amps,,, so why is my 250 amp esc faster on my 40 amp motor ????
ElectricMann is offline Find More Posts by ElectricMann
Reply With Quote  (Disabled)
Old Sep 03, 2014, 05:02 PM
Did you check the FAQ already?
SoloProFan's Avatar
The Netherlands
Joined Jul 2010
13,674 Posts
Quote:
Originally Posted by ElectricMann View Post
solo I have to disagree with u on the upper statement.. I have 5 esc.s from 45 amp to 250 amp.. by far the 250 amp esc is alot faster than all the lower amp esc and motor is rated at 40 amps,,, so why is my 250 amp esc faster on my 40 amp motor ????

Might be timing advance or turbo setting or the 250 amp ESC has higher switching frequency, so it's running more efficiently. Or it has lower internal resistance, so more of the battery's power is going to the motor, and less dissipated in heat in the ESC.

The motor can only deliver a certain amount of Watt. Since the voltage is set (unless your ESC has found a way to make the output voltage of the ESC higher than the battery voltage... ), that also limits the max current the motor can handle before it starts to fry. When that limit is reached, that's it.

Also, your motor has a kv rating, it will not be able to run faster at the same voltage, unless timing is altered, which basically alters the kv rating for that moment. That also leads me to believe the more powerful ESC is using timing advance, either static, or dynamic, so only at certain throttle percentage. And then it can indeed make your car run faster.

Did you try that 250A ESC in blinky mode, so no boost, turbo, timing advance etc are active, and then compare performance? Also a 45A ESC on a 40A rated motor is a bit on the edge, so it may struggle, especially since we don't know the peak current the motor demands when accelerating. This can also affect how the car runs, if it accelerates faster, it will appear faster, even when top speed may be identical.
SoloProFan is offline Find More Posts by SoloProFan
Reply With Quote
Old Sep 03, 2014, 05:10 PM
Suspended Account
Joined Jul 2014
791 Posts
all my tests where done with a gps speed tracker...so speed was exact .. although the 120 amp esc had a better acceleration but top speed was down to the 250 amp..No timing was used and no turbos where in able-bled..
ElectricMann is offline Find More Posts by ElectricMann
Reply With Quote  (Disabled)
Old Sep 03, 2014, 05:21 PM
Did you check the FAQ already?
SoloProFan's Avatar
The Netherlands
Joined Jul 2010
13,674 Posts
Quote:
Originally Posted by ElectricMann View Post
all my tests where done with a gps speed tracker...so speed was exact .. although the 120 amp esc had a better acceleration but top speed was down to the 250 amp..No timing was used and no turbos where in able-bled..
So both were running in blinky mode? Just how big were the speed differences? And what motor? Sensored, sensorless? A 250A ESC matched with a 40A motor goes far beyond the "golden rule" you adhere to for choosing an ESC with a certain motor. That makes it pretty unexpected to see any benefit when a lower rated ESC should already suffice by fair margin.
SoloProFan is offline Find More Posts by SoloProFan
Reply With Quote
Old Sep 03, 2014, 07:02 PM
Suspended Account
Joined Jul 2014
791 Posts
40-22mph
60-25mph
120-32mph
150-34mph
250-39-44mph
motor was a neo 1 star sensored about 4600kv gearing was 27/76-with a SMC off 4600mah 65c/130bc on a xxxt mf2 done on level cement..at 75degrees and battery was charged after each run..
ElectricMann is offline Find More Posts by ElectricMann
Reply With Quote  (Disabled)
Old Sep 04, 2014, 02:18 AM
Did you check the FAQ already?
SoloProFan's Avatar
The Netherlands
Joined Jul 2010
13,674 Posts
There must be some timing involved here, or the motor draws way more than the 40A it was rated at, and is held back a lot by the lower rated ESCs. If this situation occured all the time when upgrading an ESC, that would mean that my 60 km/h Ultima RB5 can be made to go 120 km/h with the same motor if I upgrade the ESC from a 45A to say a 120A.

Also keep in mind that for double speed, you will need more than double the power, as drag and such increase way faster than a simple linear equation, more often exponentially. So when the top speed of your car gets doubled, it means the motor has way more than double the power now.
SoloProFan is offline Find More Posts by SoloProFan
Reply With Quote
Old Sep 04, 2014, 02:51 AM
Registered User
Joined Sep 2014
8 Posts
From what i have exspieanced a motor will pull what ever it likes depending on the load it is presented with for exsamplal
i have a revo 2.5 e conviertion
greaing is 50/21
on a 2100kv 80a motor
i was pulling 120a through my 100a esc and quickly smoked this esc
puling exstra amps through a motor will generate ALOT of heat if you can dissipate this heat you can benafit from the power if not you will end up with a demaged motor the reson for wanting to try two esc's is A for fun and B because i want to try this method befor applying more/better fets to a exaiating esc
powerball250 is offline Find More Posts by powerball250
Reply With Quote
Old Sep 04, 2014, 03:25 AM
Did you check the FAQ already?
SoloProFan's Avatar
The Netherlands
Joined Jul 2010
13,674 Posts
Please make a vid when you smoke that dual esc setup. For science purposes and it may also be entertaining to watch.


Indeed if you overload a motor, it will draw more, and if you manage to keep the heating up under control, you can wrinch some more power from that motor. But you are then exceeding the specs for safe continuous use without extra measures. In such a case, i would opt for a stronger motor, that can pull off the load without extra cooling, or adjust gearing so the motor runs more efficiently. But each to his own.
SoloProFan is offline Find More Posts by SoloProFan
Reply With Quote
Old Sep 04, 2014, 04:34 AM
Registered User
Joined Sep 2014
8 Posts
Oh a vid will defo be done its fun to test out ideas floating round in my head some are betta than others lol

this will be a test to see if adding anouther esc will increase power capabilities and if thay will run together make the same choice ect

going off the vids of two motors one esc i don't see to much trouble unles to of the same esc's are dramatically diffrent
powerball250 is offline Find More Posts by powerball250
Reply With Quote
Old Sep 04, 2014, 03:11 PM
Registered User
wparsons's Avatar
Canada, ON, Whitby
Joined Aug 2008
8,934 Posts
Quote:
Originally Posted by ElectricMann View Post
40-22mph
60-25mph
120-32mph
150-34mph
250-39-44mph
motor was a neo 1 star sensored about 4600kv gearing was 27/76-with a SMC off 4600mah 65c/130bc on a xxxt mf2 done on level cement..at 75degrees and battery was charged after each run..
That's simply impossible. If those numbers were true then it would've fried the 40a ESC, not run at half speed.

Run the same tests (on video) while logging current draw.

The ESC isn't a current limiter in any way, it just pulses power. If the motor wants 100a through a 40a ESC it's going to draw until the ESC blows.

Further, motors don't draw their rated current at all times. That spec is simply the highest amount of current the motor is happy to draw continually. Actual amperage drawn will depend on load and voltage only.
wparsons is offline Find More Posts by wparsons
Reply With Quote
Old Sep 04, 2014, 03:43 PM
Did you check the FAQ already?
SoloProFan's Avatar
The Netherlands
Joined Jul 2010
13,674 Posts
I think there is way an ESC can slightly limit current. The current the motor draws depends on the load and voltage, right? If an ESC has a higher internal resistance, less voltage will be available to the motor, as a small part of total voltage will be over the ESC, and the remaining part for the motor. If the voltage on the motor is a little lower, the motor will draw less current, and I've read that motor current increases exponentially with the voltage, so the effects of a little less voltage are bigger than you would expect.

Still, I also find it hard to believe the speed gets doubled by using an ESC that can handle more amps. There must be some timing involved, the stronger ESC running more efficiently, maybe the 40A ESC was running a 4 pole motor on a 2 pole setting, so it was alternating the current switching on the coils at half the speed that it should be running at.
SoloProFan is offline Find More Posts by SoloProFan
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
For Sale Clean up sale. Pro boat 1500kv motor & two 45 amp esc's, one new and one used. DARRIN4800 Boats (FS/W) 2 Apr 25, 2014 09:17 AM
Discussion Two brushless motors on one ESC? Rob_P Dock Talk 7 Sep 23, 2013 03:20 PM
Discussion Parkzone RX/ESC to control brushless esc. Can it be done? basicmods Radios 2 Jan 26, 2008 02:15 PM
Can Two Brushless Motors Fun With One Esc airbusdrvr Power Systems 14 Jun 17, 2006 07:07 PM
Help! Two Motors With One Esc,can It Be Done ? Cr@sh Electric Plane Talk 15 Apr 10, 2006 03:47 AM