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Author Topic: Esc messing about  (Read 6437 times)

surabaya

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Esc messing about
« on: December 30, 2007, 12:57:07 am »

Hi, All
1st problem. When I powered up my boat`s electrics to test, the Esc is acting up. As soon as I turn on power, it starts the motors (without touching sticks) for a brief moment, then stops, starts, stops etc. ??? It is a 50amp job from HK, but when I first tried it it worked perfectly and I have not changed the wiring.
Also, what is the best way to wire up my two motors. At the moment, I have them wired in series but with one reversed. Would they run better if I connect parallel. At the moment they run pretty fast. They are 2 545`s and the boat is a 50" motor cruiser.
I was hoping to get it wet today >:(
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FullLeatherJacket

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Re: Esc messing about
« Reply #1 on: December 30, 2007, 09:22:26 am »

First off, I've never heard of this ESC but, in common with most high-current ones, it probably has a Battery Eliminator Circuit (BEC). If so, the problem may well be that the battery is flat. I shall attempt to explain:

Some ESCs will shut-down ("fail-safe") if they don't receive a valid signal from the Rx. Yours may be firing up but the sudden drain on the battery from the motors is dropping the battery voltage to below that at which the regulator in the BEC works, so the receiver stops sending signals out, so the ESC shuts down. As soon as that happens, the battery load reduces and the voltage to the regulator rises; the receiver then starts up again and sends a signal to the ESC; the motors fire up; the battery voltage goes through the floor again etc etc ad infinitum. Great fun for a few minutes but after that I'd sooner watch Graham Norton...........

Try charging your battery and/or using a separate receiver battery pack. I personally reckon that BEC-equipped ESCs in boats (except for fast-electrics) are more trouble than they are worth , especially for newbies - but I know I'm in the minority there!

Make sure that you're not "swamping" the receiver when you bench-test the system. Don't extend the aerial on the transmitter, although it's not a good idea to leave the Tx switched ON for more than a few minutes without the full aerial or you can damage the RF output stage through allowing it to overheat. Stand back from the model while you wiggle the sticks, and don't allow the Tx aerial to ground itself by touching anything on the bench.

If that doesn't cure it throw the ESC away and buy a proper one.........or two  ;)

Motors shouldn't be wired in series for all sorts of reasons; wire them in parallel or, better still, use a separate ESC and battery for each motor. You can always couple the ESCs with a Y-Lead if you only have two channels on your radio, or fit a mixer.

"545" can cover a multitude of different motors, from those which would rip your hand off on 6v to others which would shy away from the skin on a rice pudding. If they are direct-drive (no gearbox) then they might be too small for the model anyway. More info would be required (e.g. voltage, prop size, actual no-load current and RPM) before a conclusion could be drawn.

(Of course none of this is set in stone - just a couple of things to try, based on a heap of personal experience. Like I always say, suit yourself.)

Good luck.

FLJ
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barryfoote

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Re: Esc messing about
« Reply #2 on: December 30, 2007, 11:28:02 am »

That sounds like good advise to me FLJ but..............Graham Norton.........Graham Norton.........No never.....Under any circumstances!!!!!

Barry
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bosun

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Re: Esc messing about
« Reply #3 on: December 30, 2007, 11:43:01 am »

FLJ
Hy Dave,
 Can you use a seperate reciever pack, even if the ESC is BEC enabled ???
Cheers
Bosun
(Just another one of my daft questions)
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FullLeatherJacket

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Re: Esc messing about
« Reply #4 on: December 30, 2007, 12:19:38 pm »

Can you use a separate reciever pack, even if the ESC is BEC enabled ???
Bosun
I like your daft questions, because they ain't daft at all. If your ESC has Battery Eliminator Circuitry then there should be something in the instructions about disabling it. MTroniks' Viper manual certainly mentions this in large red letters. You mustn't try using both a BEC and a separate receiver battery together - unless you like smoke - so the conventional wisdom is to remove the RED wire from the ESC's receiver lead. If you're not sure how to do this then I have a little diagram in the form of a PDF which I can E-Mail to you if you like.
FLJ
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bosun

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Re: Esc messing about
« Reply #5 on: December 30, 2007, 01:26:07 pm »

Hy Dave.
I see what you mean by the red wire, but if you could e,mail me the diagram that would be great, I can then add that to my file marked KNOWLEDGE OF ELECTRICS (mind you the file is so small I probably wont be able to find it)  ???
Cheers,
Happy new year to you, and all at ACTion
Bosun
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barriew

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Re: Esc messing about
« Reply #6 on: December 30, 2007, 02:43:41 pm »

In case you want to use the ESC's BEC in future, rather than trying to  remove the red wire from the plug (not easy if you're ham fisted like me), buy a short Servo Extension cable and snip the red wire in that.

Barrie
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bosun

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Re: Esc messing about
« Reply #7 on: December 30, 2007, 03:09:14 pm »

Hy Barrie,
Thats another good idea mate, another one for the file.
Surabaya,,, did,nt mean to hijack your thread, but as you see the guys on here are great for tricks and info,
Bosun
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FullLeatherJacket

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Re: Esc messing about
« Reply #8 on: December 30, 2007, 05:50:00 pm »

Aw, c'mon, Barrie! This is as easy as writing a cheque........  ;)



Surabaya
Did you try charging the battery? I've just twigged that "HK" = "Hong Kong" and not some exotic UK manufacturer of electrickery! (Pauses for hollow laughter from Shanghai, T-T?)

Bosun
Right-click once on the picture above to Save Image As...... (or remind me of your E-Mail address and I'll send you the PDF). Your Knowledge of Electricity file should be big if you've a lot to put into it.

FLJ (one too many G&Ts)
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bosun

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Re: Esc messing about
« Reply #9 on: December 30, 2007, 06:45:09 pm »

Dave
 The nice thing about asking daft questions, is that all the experts like yourself very kindly supply the information that ALL us newbies can benefit from, like the diagram, simple when you know how.
Once again     (till the next time !!!)
Cheers Mate
Bosun
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surabaya

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Re: Esc messing about
« Reply #10 on: December 30, 2007, 10:39:17 pm »

Hi.
Thanks to you I now have it running,even though I feel a bit daft. :embarrassed: The battery was not charging so 1 new battery later, and it works.
As for Mr Norton, NO, I`d rather have the kangaroo motor back  {-)
Also the info about the bec came in handy too as I had the tx battery too, but no mention in instructions about not using.
Going by what you have said, what size motors would you reccomend.
Boat is 50" long & 15" beam but not as heavy as you might expect for a large boat. I don`t want it up out of the water, but a bit of wash at the front would be nice.
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Shipmate60

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Re: Esc messing about
« Reply #11 on: December 30, 2007, 11:12:46 pm »

MFA 850 on 12 volts should have it running well.

Bob

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FullLeatherJacket

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Re: Esc messing about
« Reply #12 on: December 30, 2007, 11:25:47 pm »

Good-oh! Nice when a plan comes together, innit? "Daft" is well OK - check with Bosun (and Clegg - my very favouritest Forum idiot.........!). It's "stupid" we don't very much enjoy.

We need a photo or two of your model and preferably the name of the kit or plan from which it came. A 50" scale model of a coaster wouldn't need anything like as much poke as a 1/12 scale lifeboat, and there's plenty of room for further confusion in between.

There's over 1700 members of this Gentlemen's Club, and so it's fairly certain that at least ONE of them has built either the same model or something very like it. Let us know what you have and the problem will magically go away (OK - there may be a bit of argument in the process, but it helps oil the wheels of advancing senility.......).

FLJ   8)

Just realised I left the centre socket showing inside the plug-shell sketch..............looks like Hara Kiri time again.  :embarrassed:
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surabaya

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Re: Esc messing about
« Reply #13 on: December 31, 2007, 12:45:48 am »

Well here she is. I don`t know what kit as I got as a restoration. Was in a bad way, cracked and a hole in hull plus bits missing.
It now has 2 motors, 2 rudders, 50 amp Esc, acoms servo, rx and tx, 12v 4.5 ah battery.
I think it is coming along and can`t wait to get it in the water, but still a little more to do, like stanchions.I know there are a lot better efforts around, but I will learn. ( Hopefully from the masters). ;D
Would be grateful for any comments or idea`s.
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Shipmate60

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Re: Esc messing about
« Reply #14 on: December 31, 2007, 12:48:37 am »

Yep, MFA 850 on 12 volts.

Bob
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FullLeatherJacket

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Re: Esc messing about
« Reply #15 on: December 31, 2007, 09:09:46 am »

Looks very pretty; I think PMK had one very similar until it met with the Mad Swan of Somerset! A Fairacre?

Bob may well be right about the MFA motors (I take it you mean two of 'em, Shipmate?). Meanwhile I'd suggest you try the model out with the motors which are already fitted. If they rev like mad and the model goes nowhere then try larger props. If the motors get hot then they're being overloaded, so you may need to replace them with something more torque-y.

Your choice then would be either big, fat things on direct drive like the 850 or geared 540-sized ones like the MFA Torpedo 500 6:1. Neither will cost the earth and can be used with the present ESC if you wish.

FLJ
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barriew

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Re: Esc messing about
« Reply #16 on: December 31, 2007, 11:31:52 am »

Aw, c'mon, Barrie! This is as easy as writing a cheque........  ;)


.....what are those?  {-)  Can't remember the last time I used one. ;)

Barrie
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surabaya

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Re: Esc messing about
« Reply #17 on: December 31, 2007, 01:43:43 pm »

Hi, sounds good to me, maybe I can sneak off tomorrow for a bit at the local river. We are lucky to have a very slow running river/canal nearby.
Does anyone have any pics of the fairacre you mentioned, I would love to see how it`s done.

P.s before I get the comments,"a bit of time at the river",is what I meant.  :D
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Shipmate60

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Re: Esc messing about
« Reply #18 on: December 31, 2007, 04:07:57 pm »

2 x 850's on 3 blade brass props should move her nicely, and if she is a bit overpowered you don't have to use it all, but it is nice to be able to get out of the way sometimes.

Bob
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dougal99

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Re: Esc messing about
« Reply #19 on: December 31, 2007, 05:08:04 pm »

Really nice looking model Surabaya. I would think 2 x 850's would have you sailing all day on a single battery charge. I've got an 850 fitted to my Sea Queen (46")which gets nicely up on the plane.

Best of luck at the river tomorrow.  O0

Doug
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Shipmate60

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Re: Esc messing about
« Reply #20 on: December 31, 2007, 06:47:17 pm »

What size props are on her?

Bob
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surabaya

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Re: Esc messing about
« Reply #21 on: December 31, 2007, 10:30:01 pm »

Hi,
Props are approx 50mm / 2".
Do you think I would be better with gears fitted or just direct drive
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Shipmate60

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Re: Esc messing about
« Reply #22 on: January 01, 2008, 12:00:50 pm »

I would go for direct drive, but try her on those props, but they might be a bit big and she will fly.
Id she is too fast or power hungry go for smaller props.
The MFA 850's rev at 9000 rpm so underpropping will still give good performance but less load on the motors giving more duration.

Bob
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surabaya

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Re: Esc messing about
« Reply #23 on: January 01, 2008, 10:02:15 pm »

Thanks, I will give it a go.
Any suggestions where to buy at reasonable price. I have heard of model motors direct, but cannot seem to find them.
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Shipmate60

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Re: Esc messing about
« Reply #24 on: January 01, 2008, 10:13:22 pm »

Model Motors Direct
Keepers Cottage
Home Farm
Iwerne Minster
Dorset
DT11 8LB
01747 812440

Alistaire sells some superb multi-pole motors, but they are more suited to Tugs or small Warships.

Before any of you start by saying he sells all sorts of motors, I have had several "Discussions" with Alistaire and have yet to be supplied by him of any large Medium to Fast Motors.
I have tried most and are still running some 777 motors.

Bob
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