Twin Brushless Set Up

[Paul TParticipant @pault84577]

Has anyone got a simple wiring diagram for a twin brushless set up.

I am looking for a system having twin motors, twin ESCs but using a single stick on the tx.

Paul

[Paul TParticipant @pault84577]

[Malcolm FraryParticipant @malcolmfrary95515]

If both motors are run together, a three wire Y lead to connect the ESC to the RX and a big knobbly Y lead to hook the battery to the ESCs. (Black to black, red to red)

[Kev.WParticipant @kev-w]

For brushless, it is 3 wires from esc to motor instead of 2.

Edited By Kip Woods on 30/03/2017 23:20:55

[Dodgy Geezer 1Participant @dodgygeezer1]

In theory you should not be able to run two brushless from a single ESC, since the ESC depends on feedback from the motor to adjust its switching rate, and two motors ought to confuse it.

In practice there are reports that it can be done. See **LINK** for instance.

Don't get me onto the more esoteric problems of running two motors in series from the same battery! But the link I gave does touch on the interesting issue of running two brushless motors from a single ESC on the same shaft…

[Paul TParticipant @pault84577]

Dear All

Thank you for your answers, If I use Kips very helpful drawing to explain my lack of understanding you might better understand my query.

Does the straightforward connection (shown in red) provide a constant and equal 50/50 split of the signal from the Y lead or do I need some kind of mixer?

[Dave MilbournParticipant @davemilbourn48782]

Paul
Not that it's in any way in my nature to disagree [well, not often] but in my opinion trying to double up two motors onto one ESC and/or battery is just asking for trouble, especially with brushless motors. My advice is always to treat a twin-motor installation as two single motor ones i.e. fit two of everything. That way a) it puts less load on the batteries and ESCs; b) if there is a fault it's easier to find and fix, and c) you're still left with one functioning motor if the other fails while sailing.
The second point is that twin motors with two ESCs allows you to use tank-steering – far superior to a mixer for low-speed manoeuvring.
I've just seen your post above as I hit the Send key on mine. The answers are respectively Yes and No, but see my comments earlier.

DG
If you need extra power on one shaft then why not just fit a more powerful motor – unless you're the type that also likes standing up in a hammock?

Dave M

Edited By Dave Milbourn on 31/03/2017 11:40:55

[Dodgy Geezer 1Participant @dodgygeezer1]

Posted by Dave Milbourn on 31/03/2017 11:38:27:

DG

If you need extra power on one shaft then why not just fit a more powerful motor – unless you're the type that also likes standing up in a hammock?

Dave M

Edited By Dave Milbourn on 31/03/2017 11:40:55

I've never wanted twin brushless on one shaft – this is Amos of RC Groups talking! Since he's a flyer, perhaps he wanted lots of power with a low frontal cross-section?

In any case, he is able to quantify the disadvantages from practice, which is always useful…

[Dodgy Geezer 1Participant @dodgygeezer1]

Incidentally, we haven't mentioned the BEC issue.

ESCs often provide a BEC service to power the receiver. If you have two ESCs you have two BECs trying to power the receiver, and this may cause problems. I would take the RED wire out of one of the ESC sockets and tape it back on the wire so it can be used again if necessary. This means that only one of the ESC BECs is providing power to the receiver.

If you are using a separate receiver battery (a better solution) I would remove the red wires from both ESCs if they include BECs. This link may help… **LINK**

[Dave MilbournParticipant @davemilbourn48782]

DG

Nothing personal, old thing. I used the word "you" where, more correctly, I could have used "one" i.e. "if one were to require additional power on one shaft then why would one not fit a more powerful motor – unless one was also of the type inclined towards standing up in a hammock". However not many folk respond favourably to such arcane grammar, hence the more colloquial "you". I doubt that Oxford English is the first language of Amos of RC Groups anyway.

BEC is a subject which is understood by relatively few. Amazing really, because it's so straightforward. I totally agree about using a separate battery pack for the receiver but sometimes either weight or space precludes this.

DM

[Paul TParticipant @pault84577]

Why is it that whenever I ask a simple question the answer has to include Amos in a hammock trying to steer a tank through Oxford with a side order of BECs marinated in red wires.

So before we descend into the depths of arcane grammar and discussions about the validity of using quantum theory to prove that never ending gobstoppers actually travel backwards in time can we just establish that Kips very helpful drawing is the answer to my query.

Can I assume that if I have 2 batteries, 2 ESCs 2 brushless motors with a single receiver and that I get the sellotape tight enough on the Y lead Y connection then everything is ok?

Paul

[Dodgy Geezer 1Participant @dodgygeezer1]

Ah, sorry, DM, I must be getting touchy in my old age! Put it down to being late for my midday beer.

 

I also concur with your general principle of treating each engine in a multi setup as a single item with its own ancillary services if possible. Much better practice and more flexible/resilient. 

Edited By Dodgy Geezer on 31/03/2017 15:26:43

[CookieOldParticipant @cookieold]

Paul , I have 2 Brushless motors , each with its own Esc . Esc,s on a Y lead to the receiver , all BEC,S disconnected and use a separate receiver battery , no issues at all.

Best Regards Dave

[Paul TParticipant @pault84577]

Thank you Dave for a nice straightforward answer.

All the best

Paul

[Former MemberParticipant @formermember84718]

[This posting has been removed]

[Dave MilbournParticipant @davemilbourn48782]

Presumably you mean a model-size version? If so, how big (L x W) and how many motors? Are you proposing to use a model outboard motor? At the moment we don't have enough detail to help you.

DM

[Former MemberParticipant @formermember84718]

[This posting has been removed]

[Ray Wood 3Participant @raywood3]

Hi Will,

You could buy a kids inflatable beach dinghy that size ? Why you would want to put an out board on it is beyond me 😀 although you can buy inflatable jet skis with electric motors for kids (at Harrods) 👍

Regards Ray

Edited By Ray Wood 2 on 28/07/2020 15:22:24

[Malcolm FraryParticipant @malcolmfrary95515]

Model inflatables are not usually inflatable. They just built and finished to look that way. Cunningly cut plastic conduit or drainpipe is the usual choice.

An actual inflatable model, loaded with a lot of moneys worth of gear runs the risk of becoming deflated when "out there". If a real one starts to deflate while manned, it has a good chance of the problem being spotted by the crew and action taken in time to get it to shore, because they have a vested interest in not drowning. With a model, by the time a problem gets noticed, it might well be too late to recover it.

[Paul TParticipant @pault84577]

Nice advert for inflatables

[Dave MilbournParticipant @davemilbourn48782]

Posted by Paul T on 28/07/2020 16:45:38:

Nice advert for inflatables

Any particular brand, do you suppose?

DM

[CookieParticipant @cookie15923]

Paul , i run 2 identical brushless motors with 2 identical speed controllers on a Y lead from the receiver with no issues Regards Dave

[Scott HuntleyParticipant @scotthuntley28368]

Hi Paul T.

Did your plan as per the drawing work? Some of later comments it looks like it should, ONE is thinking of doing the same on my sons boat.

regards Scott

[ashley needhamParticipant @ashleyneedham69188]

Hi Scott and welcome to the forum.

As per Cookies post above yours, this combination should work fine no probs.

The esc take the same inputs regardless of being brushed or brushless, so a Y lead is fine.

If using the BEC facility for Receive power, simply disconnect the red wire on one of the esc servo leads so that only one esc provides the BEC. Use a pin or scalpel to press down the tang in the plug and pull out the red wire…tape up to stop any shorting out. This is better than cutting the red wire as it means you can use the esc for BEC in the future.

If using a separate Rx battery, disable red wire on Y lead to prevent “double receiver battery supply” issues.

Ashley

 

Edited By ashley needham on 18/09/2021 09:47:03

[Paul TParticipant @pault84577]

Hi Scott

Yes it worked very well and Ashley has summarised it better than I could.

Paul

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