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Author Topic: OK so what am i doing wrong???  (Read 15369 times)

whiskeyfrank

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Re: OK so what am i doing wrong???
« Reply #75 on: August 21, 2008, 09:54:55 PM »

battery connections are fine just tried some new ones

but, ive just metered the batteries and one is 6.23v and the other is 6.31v, not sure if this difference is significant enough but would this combined voltage is too much for the esc which is rated at 12v
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DickyD

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Re: OK so what am i doing wrong???
« Reply #76 on: August 21, 2008, 09:56:30 PM »

Dont know if I am right but there is an awful lot of joins, plus it doesn't look as if the motor is suppressed John. O0
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DickyD

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Re: OK so what am i doing wrong???
« Reply #77 on: August 21, 2008, 09:57:59 PM »

Have you tried both batteries seperately ?
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whiskeyfrank

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Re: OK so what am i doing wrong???
« Reply #78 on: August 21, 2008, 10:07:14 PM »

just tried each battery and they both work fine. The motor was suppressed but i took them off while i was moving the motor, both to the body of the motor and across. tried with them back on and no difference.

There are a lot of joins as ive been trying lots of things, ive metered them all and they are all fine.

just wont work with 12v.

Is there  wiring diagram anywhere for 2 batteries and 1 esc, i looked all over the forum? just in case im wrong.

im going to take the batteries to less than 12v combined and see what happens
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John W E

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Re: OK so what am i doing wrong???
« Reply #79 on: August 21, 2008, 10:09:12 PM »

Hi what is the combined output voltage when both batteries are wired up ,using the meter to test

john
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DickyD

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Re: OK so what am i doing wrong???
« Reply #80 on: August 21, 2008, 10:19:23 PM »

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malcolmfrary

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Re: OK so what am i doing wrong???
« Reply #81 on: August 21, 2008, 10:22:52 PM »

Hi what is the combined output voltage when both batteries are wired up ,using the meter to test

john
Quite importantly, wired up and under load.
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OMK

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Re: OK so what am i doing wrong???
« Reply #82 on: August 21, 2008, 10:37:09 PM »

Frank,
A silly question, but you don't suppose you've got a dodgy cell in one of your batteries, do you? If that is the case it is possible that your voltmeter would show a healthy reading of the (unloaded) battery voltage, but it's also possible that the voltage may be dropping waaaay more than it should when you connect the load (the motor). Just out of curiosity, have you tried omitting the ESC and connecting the motor directly to the batteries? Connect your voltmeter across the motor terminals (with the two batteries connected at the same time) and see what sort of reading you're getting.
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whiskeyfrank

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Re: OK so what am i doing wrong???
« Reply #83 on: August 21, 2008, 10:50:56 PM »

they show 12.5v together, and ive tried the motor without the esc and it spins much after (of course).

ill have a look at the articles on that link and keep trying
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whiskeyfrank

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Re: OK so what am i doing wrong???
« Reply #84 on: August 21, 2008, 10:54:25 PM »

Thanks for the help guys, im off out and away for a couple of days and will try again when i get back.

Must get some rest from my soldering iron burns!!
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OMK

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Re: OK so what am i doing wrong???
« Reply #85 on: August 21, 2008, 11:01:00 PM »

In that case, I'll be the first to stick my hands in the air and admit.... I just don't know the solution.
It's weird that it (the ESC) should run on 6v but not 12.

Like someone else already said - maybe there's some sort of failsafe kicking in.
Or maybe the damn thing is shot to bits after all.
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barry park

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Re: OK so what am i doing wrong???
« Reply #86 on: August 22, 2008, 06:47:28 AM »

Hi Whiskey,
Look here because you have two similar in your esc and they are blocking your motor.....http://www.farnell.com/datasheets/33634.pdf

Which protection mechanism in the list below tells me your test bulb was 230 volt or came out the trash bin?    :D
I'll bet if you tried a 12 volt headlamp bulb the result would have been different ...it would have proved your esc was  O0
I was on the case from the beginning but you gave a bum steer with the result of the bulb test.
Here's the list from that link if you have an aversion to 16 pages of jargon.

 Overload protection
 Current limitation
 Short circuit protection   ;) When you drop to a 6 volt pack your stall current is halved and falls below the trip point
 Overtemperature protection
 Overvoltage protection (including load dump)
 Clamp of negative voltage at output
 Fast deenergizing of inductive loads
 Low ohmic inverse current operation
 Diagnostic feedback with load current sense
 Open load detection via current sense       ;)  ESC saw your bulb as open circuit as it was not enough load.

.... I think you've enough to blow a 15 A fuse in 2 secs.
Long term........
You're running a 700bb motor on 12 volt ?? What sort of prop and what reduction gear ratio?
Do you know what shaft revs you'll get with your prop at full throttle?
Do you know what current drain,power output,efficiency that will give?

Look here and you'll see what I'm hinting at with the above quote .... http://www.johnsonmotor.com/Performance-Charts.266.0.html

Horizontal torque axis equates to prop size.
 Click on the Typical Applications and you'll find what Martin ,the forum admin,thinks are bad motors.
They are for cordless drills with a 100:1 reduction gearbox ....absolutely no use for direct driving a boat prop through water because they have a low torque/amp ratio. They need gears to drive any sort of load at all.
Stick them in a boat and the prop whines like a banshee in air.   Sink the prop under water and and it slows to a crawl.

The 700 motor is not that low a torque but you'll have to watch your prop size or you'll be on the stall half of the motor which is to the right of max power.
A rule illustrated on the graph , is if full throttle revs in water fall to less than half free running shaft speed ,the prop is too big.
You can see that point in black and white if you navigate to an actual motor page.....
 http://www.johnsonmotor.com/mediando/index.php?IdTreeGroup=49&IdProduct=459
.....and scroll to the foot of the page.
I'm thinking you have a turbo and not a torque version of the 700.
I also bet the 700 will blow a fuse the first long  burstin the water.You'll need to change the rating....that's OK cause your esc protection will actually react faster to your prop snagging on something.
Good luck anyway and I'm glad you got back on track. :)
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OMK

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Re: OK so what am i doing wrong???
« Reply #87 on: August 22, 2008, 08:10:04 AM »

Mercy sakes alive! :o
They teach 'em to talk to the talk, but they don't teach 'em how to listen.  {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-) ;D {-)

(And I normally never ever use smileys).
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DickyD

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Re: OK so what am i doing wrong???
« Reply #88 on: August 22, 2008, 08:36:30 AM »

What is he on about PMK, no dont bother trying to explain it I didnt get a degree inelectrothingamejigs.

Does the man not speak English ? :-\
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Martin13

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Re: OK so what am i doing wrong???
« Reply #89 on: August 22, 2008, 09:40:53 AM »

Huh ??? :embarrassed: :-X :-\ :o you lost me

Martin du
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John W E

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Re: OK so what am i doing wrong???
« Reply #90 on: August 22, 2008, 12:32:16 PM »

Richard - Martin

from what I can make out through me garbage filter  ::)  what the man from rubbish heap is trying to say is

that the speed controller has built in safety; and, the motor that it is trying to drive with it is a super dooper one...

so, when it does kick off, the initial serge generated trips the speed controller in milliseconds...  :P me thinks

What we really need on this Forum, instead of a spell checker is a smell checker that sniffs out any garbage junk that is going to be typed and kicks it out..... :angel:

bluenird - time for revenge
 ;D
aye so it is.....  O0
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Martin13

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Re: OK so what am i doing wrong???
« Reply #91 on: August 22, 2008, 01:11:21 PM »

Richard - Martin

from what I can make out through me garbage filter  ::)

What we really need on this Forum, instead of a spell checker is a smell checker that sniffs out any garbage junk that is going to be typed and kicks it out..... :angel:

bluenird - time for revenge
 ;D
aye so it is.....  O0


Hey John,

Can I have a copy of your garbage filter/translator {-) {-) {-) O0

Martin du :angel:
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DickyD

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Re: OK so what am i doing wrong???
« Reply #92 on: August 22, 2008, 01:45:10 PM »

Me too John  O0
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barry park

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Re: OK so what am i doing wrong???
« Reply #93 on: August 25, 2008, 12:23:32 AM »

...........................................................................This link has expired
.                                              http://www.farnell.com/datasheets/33634.pdf
But the same info is here           http://www.datasheetcatalog.org/datasheet/siemens/BTS555.pdf
The bulleted list includes feature of the ESC that doesn't like a 700BB Turbo.
Longer (or smaller gauge) motor leads is a simple cure.
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wombat

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Re: OK so what am i doing wrong???
« Reply #94 on: August 25, 2008, 08:19:07 AM »

Didn't I say this a page or so ago?

Still nobody listens to me  >>:-( :'(
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FullLeatherJacket

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Re: OK so what am i doing wrong???
« Reply #95 on: August 25, 2008, 09:27:58 AM »

Didn't I say this a page or so ago?

Still nobody listens to me  >>:-( :'(

Wom
I listen to you, sweetheart............it's just that sometimes you don't seem to write enough.......... :o :o
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sweeper

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Re: OK so what am i doing wrong???
« Reply #96 on: August 25, 2008, 05:06:48 PM »

Quote
What we really need on this Forum, instead of a spell checker is a smell checker that sniffs out any garbage junk that is going to be typed and kicks it out....

I would have thought that you would have come across these devices some time ago Bluebird.
We were issued with them at work (prior to having to listen to a lecture from management), went by the name of an "OXOMETER". ;)



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