Terry.
Agreed.
Regards
Bill.

This thread has become very complicated. Just do what everyone has no doubt tried Experiment .you blow a speed controller you buy a better one or like me you have a good friend called Ali express lol

Good morning Doug.
Thank you for your comprehensive, precise and detailed response.
Now I understand correctly.
I read several times to better translate.
I would never have done this:
"on no account should the positive (red) motor leads of a dual ESC speed controller be connected together!"
Not even before knowing your answer.


Good morning Lew.
You're right, I was speaking in general, about the ESC "Putting the pedal to the floor (on a RC transmitter) is ramping up the voltage".
I do all the measurements with the stick at maximum.

Thanks to Lew and Doug.
Now I understand the meaning of your interventions much better and I thank you because I am a little less ignorant than before.

Perhaps we might have overlooked something: "Maximum Power". Putting the pedal to the floor (on a RC transmitter) is ramping up the voltage. Possibly a perception mis-use when comparing to amperage?
Lew
Florida, USA

Hi Alessandro,
Ref your query-
"I wasn't talking about making a Y branch on an ESC to control two motors. Mine was a question not a statement.
Rather, I was asking if the ESCs, already built with double outputs at the factory, are not in fact like this, that is, we do not have a Y connection (a parallel between the outputs), which we do not explicitly see. Or do they have more electronics than single output ESCs?"

My dear Alessandro,
Dual ESC means exactly that. Two complete and independent ESCs are included in the package. Some also include rudder mixer circuits to automatically adjust the motor speeds according to the rudder commands.
E.g. for 'rudder hard to port' the port motor would be automatically commanded to run slower or even in reverse to assist the rudder command. Programmable by the user.
ON NO ACCOUNT SHOULD THE POSITIVE (RED) MOTOR LEADS OF A DUAL ESC SPEED CONTROLLER BE CONNECTED TOGETHER! WHY?
Because they are the outputs of two totally independent ESC circuits which may be carrying different control signals (pulse trains) to the two motors, especially if the dual ESC includes the rudder mixer function or a separate mixer unit is attached.
Or if independently operated from the TX (so called Tank Steering) the control pulses will be different according to the operator's commands.
Thus connecting the two red leads of a Dual ESC will likely result in serious or terminal damage to it. At the very least loss of control of the model😭
Lew is also right that stall current of the motors is more important than power when scaling an ESC for a boat and it's motor.
Power is about performance, stall current is about survivability of ESC, motor --> model.
Doug 😎

Evenin' All,
I have watched this thread with interest, and occasionally some amusement😉 or despair.😮
Lew came closest to the right answer👍
Not all ESCs, even today, include overload protection. And the reaction time, i.e. before disaster, is never quoted. Never mind us oldies who still have several older working ESCs without such alleged protection.
So Phil, the basic answer to your original question is YES YOU CAN😊
But there are certain precautions to be taken.
As others have rightly said👍 the ESC must be capable of handling the total current draw of both motors under load. (Simple Vulcan logic Jim😁)
But Lew finally hit the nail on the head with Stall Current!
And this ties in with Bill's "not recommended" comment. To whit, 'if there's a problem, e.g. stall, with one motor both will be out of commission and the boat stranded'.

Not necessarily Bill! Simple remedy to this is just fit quick blow fuses in the + leads to each motor, value a few amps below the rated stall current of the motors.
Then if one motor stalls the fuse blows and isolates it from the ESC and second motor.
So with the second motor (and some skilful course rudder corrections to compensate for the asymmetric thrust😉) you can make it back to base.
I have run my twin shaft destroyer this way for 30+ years without problems.

PLEASE NOTE EVERYONE- THIS ONLY WORKS WITH BRUSHED MOTORS!
YOU CAN NEVER UNDER ANY CIRCUMSTANCES USE ONE ESC TO DRIVE TWO BRUSHLESS MOTORS!!!! WHY?
Because (regardless of In- or Out-runner) the Brushless ESC electronics must know, in real time, where the rotor (the rotating bit😁) is in relation to the stator, the static bit which you have bolted to your motor mount.
To enable this Brushless motors send feedback info to the ESC either from built in sensors or, in the cheaper but no less effective sensor-less versions, by monitoring the back emf pulse (voltage spike) created when the last stator pole (coil) was switched off.

(As Faraday discovered but Tesla first really understood and used in his ground breaking inventions - when a current flows through a coil both an electric AND a much stronger magnetic field are created around the coil. When the current is shut off these fields collapse and their energy flows back into the coil, producing the voltage pulse, the back emf (electromotive force😁) which the ESC registers).
Still with me folks? WAKE UP AT THE BACK THERE!!
So you can guess the problem😉
If the ESC receives two feedback signals from the two motors how should it know which to react to? It will likely go schizophrenic or into a catatonic coma.
Either way it will probably be totally confused and 'out of service'.
I haven't tested this, and don't propose to risk my hard earned ESC/motors by doing so.
But it is sure that 1 ESC to 2 brushless motors is a NO GO!
Cheers, Doug😎

Hello Commodore H.

You wrote: [I believe you are “over thinking” this.]
You're right! reason to sell, ahahahahah.

I think about it too much; This forum actually interested me a lot due to the topics covered and I'm spending a lot of time there.
I've never spent so much time on the internet, so much so that my wife is getting suspicious.
In my opinion, she suspects that I have a lover, or that she is in some "strange" chat. ahahahahahaha.
Will you tell him, please, that I only write about naval models?

it's AndyN's fault!
joke I have to thank AndyN who introduced me to this forum.

I believe you are “over thinking” this.
I prefer Mtronics speed controls. In the event of signal loss they will just shut your motors down. They are simple to set up. If you don’t need independent control for maneuvering two motors in parallel works just fine. The current draw of the motors is different if the boat is held in place or moving in any case.
I like the 20amp esc version. You can buy one and if your not happy later buy another one.

Hi Bill and Lew, thanks for your input. I'm learning a lot.

Consider that, as I am not a modeler of RC planes and helicopters, I am almost unfamiliar with radio controls. I'm just learning them.
I rely mostly on memories of electricity and electronics that I had as a boy. Distant memories.

I hope I understood your comments correctly.


To Bill.
I agree with you, with two motors I would also prefer two ESCs, but for different reasons.
I wasn't talking about making a Y branch on an ESC to control two motors. Mine was a question not a statement.
Rather, I was asking if the ESCs, already built with double outputs at the factory, are not in fact like this, that is, we do not have a Y connection (a parallel between the outputs), which we do not explicitly see.
Or do they have more electronics than single output ESCs?


To Lew:
I don't know if I understand everything, I hope so.
The economic argument is very clear.
Before assimilating the information I am reading in this forum, I would like to make sure I understand correctly.
Therefore, the direct current electric motor, if braked or even blocked, absorbs much more current than a free motor. This is clear. I consider a propeller engine spinning in water without impediment other than fluid friction.
The ESC, as you say, has its own protection in case of overload. Ok I think I understood correctly.
Certainly the most important factor to consider is the inrush or stall current, perhaps I mistranslate.

But I don't understand why you don't look at the maximum power.
When I imagine electrical loads (users) I have to be careful, in the electrical field, that their absorption powers are not higher than the power supply. For example, if an electrical device normally absorbs 4 Amperes, I cannot power it with a device that is capable of delivering a maximum of 2 Amperes. In this case the power supply unit would be damaged.
Isn't this discussion applicable to motors and ESCs?
In other words, reformulating the question: If I power an electric motor with a single ESC, then add another in parallel, then another, then yet another and so on, I do not reach a point where the absorbed current is too much, even if there are no impediments on the crankshafts?
Loads in parallel decrease the equivalent resistance and therefore increase the absorbed current.
Even if a power supply or voltage regulator can withstand high inrush currents, is it capable of managing steady-state currents much higher than expected? If so then I'm learning something new.
Ah, logically I talk about absorbed current and power as if they were synonymous. Of course this is not the case, but I am only referring to the consequences of the Joule effect and at the same voltage, of course.

Then I thought, perhaps Lew knows very well the characteristics of the ESCs on the market and already knows that none of these can be put into "difficulty" by two brushed electric motors. So he makes a purely practical and pragmatic assessment rather than theoretical.
For example: "we know that the cheapest and poorest ESC makes up for 30A (I say randomly) and a motor normally, without impediments on the axis, absorbs around 4A (I say randomly), so I'm always calm because or one or two deaths makes no difference."

I repeat, mine are more questions than statements. Before assimilating I prefer to be sure that I have understood correctly.

Morning Alessandro.
Sorry for the delay but only just see your reply along with all the other valuable info given by others.
Lew give a brilliant input into the situation 👍 and I agree.
I have to be honest and say that I am unsure concerning the internal workings re the two way and single ESC other than stating the obvious.
I personally wouldn’t use a Y lead.
With two motors on a single ESC the problem will be if one motor goes wrong the other could be uncontrollable.
I have and still do run two of one ESC in one boat without a hitch🤞🤞
Not sure if this makes sense.
I like you am always keen to learn from those who know more than me.
Regards
Bill.