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Author Topic: My Boats are running Slow  (Read 1174 times)

Buccaneer

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My Boats are running Slow
« on: September 07, 2021, 11:50:01 am »

I have a problem in that some of my boats are running slow.
Situation: I have four boats, 2 x Puffers, a Tug and a Merchantman, all fitted with a Mabuchi 555 Motor, Action P79 or P80 ESC and controlled by a Futaba 6EX 2.4 GHz Transmitter. All boats are run from 12V SLA Batteries. The Transmitter was purchased on 13 July 2007. All boats run from the same channel on the Transmitter, which controls Motor and Rudder only.
All was well until about 6 months ago I noticed that I was not getting full power in forward selection. A check of the output from the ESC’s showed a maximum voltage of about 11-11.4 volts.
I checked performance using a different Channel on the Transmitter and output increased to just about 12V, but is showing signs of dropping off again. I have always set the neutral (STOP) position of the throttle to the mid point on the Transmitter before switching ‘ON’. By setting it slightly into the ‘Reverse’ segment before switching on I am able to get up to about 12.2V from a freshly charged Battery and get a realistic speed from my boats.
Is my Transmitter slowly dying?, or does anybody have any other suggestions please?
John
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Shipmate60

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Re: My Boats are running Slow
« Reply #1 on: September 07, 2021, 12:45:09 pm »

Is the rate adjustable on channel 3?


Bob
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grendel

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Re: My Boats are running Slow
« Reply #2 on: September 07, 2021, 03:22:21 pm »

I had a similar issue which I found to be the fact I was using reverse (on the esc) as forward, reverse had less power, I ended up reeversing the wiring to the motor, and then had full power in forward, slightly less in reverse, but it still starts in the correct direction 90% of the time (must be how the throttle lever is set when you connect.
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Tug Fanatic

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Re: My Boats are running Slow
« Reply #3 on: September 07, 2021, 03:28:14 pm »

I would be very surprised if the transmitter was failing.

I agree that is sounds like a rate switch issue. It is common for throttle channels to have settable limits so that linkages to carburettors can give idle to full power without binding and also variable throttle curves (exponential).

I have also used the limits to calm digital young fingers (off/ full on/ full reverse with nothing in between & executed at great speed).
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Martin (Admin)

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Re: My Boats are running Slow
« Reply #4 on: September 07, 2021, 03:34:09 pm »

I had a similar issue which I found to be the fact I was using reverse (on the esc) as forward, reverse had less power, I ended up reeversing the wiring to the motor, and then had full power in forward, slightly less in reverse, but it still starts in the correct direction 90% of the time (must be how the throttle lever is set when you connect.

Yes, I've seen that.
Many ESC have limited current in reverse......
unlike some tanks in WWII !
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chas

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Re: My Boats are running Slow
« Reply #5 on: September 07, 2021, 03:35:23 pm »

There are a few possibilities, but I think you should start at the beginning, check the voltage of the batteries, with everything powered up and running. You are looking for 13 volts plus on a charged sla. 12 volts or less is a problem, but as I can't be sure if your esc s drop the voltage a little,  the battery should be the first check.
  The fact that your models used to run properly, but now don't makes it very unlikely that there is an issue with the settings. Also you say that the problem is on more than one boat so it must be something that is used in various models, the battery is the obvious suspect.
  If you check the voltage with the model in the bath and running, you
Might find the voltage dropping a lot further
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Shipmate60

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Re: My Boats are running Slow
« Reply #6 on: September 07, 2021, 06:17:55 pm »

What Speed Controllers are you using?


Bob
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Tug Fanatic

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Re: My Boats are running Slow
« Reply #7 on: September 07, 2021, 06:28:43 pm »


..............  The fact that your models used to run properly, but now don't makes it very unlikely that there is an issue with the settings. .........


I would agree except that there are lots of switches & dials on transmitters these days. It s very easy to flick one accidentally and find that it is set as a dual rate switch or a mix switch.
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Buccaneer

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Re: My Boats are running Slow
« Reply #8 on: September 07, 2021, 07:22:14 pm »

Thank you for your inputs so far. Each boat has it's own Battery and they are charged in situ so I don't think that can be the problem. The fact that they used to run ok but are now giving this problem rules out the 'running motors in reverse' situation mentioned by grendel - I think!


For Shipmate 60 I amusing Action Speed Controllers.
I have been through the Instruction Book again, most of it is double dutch to me I am afraid. I did find a reset procedure in which all settings are reset to the manufacturers settings so I will give that a go tomorrow morning and hopefully be able to check it out in the afternoon.


Thanks again
John
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Tug Fanatic

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Re: My Boats are running Slow
« Reply #9 on: September 07, 2021, 07:57:33 pm »

You could try these 2 simple procedures which I suggest bearing in mind that I don't know your transmitter.

Flick each switch on the transmitter and see what difference it makes. Put switch back to the original position & try the next switch.

If you have set each model as a different model number on your transmitter then this won't apply but if they are all the same number then just try running any model as a different model number. That should remove any odd programming on the one model used on the transitter.
 
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roycv

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Re: My Boats are running Slow
« Reply #10 on: September 07, 2021, 09:43:15 pm »

Hi sorry to mention the obvious but have you checked that the prop shafts and motors are moving easily.  May need a drop of oil?
Good luck
Roy
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chas

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Re: My Boats are running Slow
« Reply #11 on: September 07, 2021, 11:27:46 pm »

When trying to trace a fault, it's best to be methodical and systematic, which is why I suggested starting with the power source. Presumption isn't the same as knowing, a faulty charger or battery could easily lead to an undercharged power source.
  The 12.2 volts you mentioned in a lead acid battery is 50% charge, and that voltage might we'll drop when a load is applied. A very simple check taking a couple of minutes will confirm whether the battery is ok or not . If the battery is ok, then move on with a servo in the esc socket on the receiver to check for full movement, much better to check properly than just randomly trying things.
 
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roycv

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Re: My Boats are running Slow
« Reply #12 on: September 08, 2021, 05:54:33 am »

Hi Chas is right in his approach.  Each boat should be looked at separately, sometimes you can have too many facts, but you made the point that the commonality is the Radio and that sounds OK.  A fully charged single lead acid cell shows 2.4 volts off load.  So 6 cells (nominal 12 volts) should show 14.4 volts again off load.  Do you have a meter able to read this?

You can expect the performance of SLA batteries to drop off a bit in use and not have as much capacity as they started with.  Another thing with SLA batteries is that they need regular topping up, at least monthly to stop the internal chemistry deteriorating.  You should not leave them as you can NiMh batteries. 
One more fact and that is that SLA batteries are charged differently to NiMh and so you should leave them on charge until they go over to trickle charging.  This is called taper charging and if you use an intelligent charger it will be doing this.

Hope this helps, I stopped using them some years ago due to the high maintenance, but they make good weights when glueing wood!
Regards
Roy
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malcolmfrary

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Re: My Boats are running Slow
« Reply #13 on: September 08, 2021, 09:48:28 am »

While the transmitter is a common point, unless a setting has been accidentally tweaked, it is highly unlikely to be the culprit.  Digital devices work fully until they don't, and then they don't work at all.  Generally.
The common item with the batteries is the charger (apart from their age).  A smart charger that runs into "unexpected conditions" will often claim to have done its job when in fact it hasn't.  A session using a dumb charger and a meter can tell whether things are working as they should.
Roycv's check will help.  Check the voltage as charged, under load, and again after use under load.  A nominal 12 volt battery that drops below 13 volts under anything but extended use is suspect, but only after charging with a "dumb" charger.
The control pot in an old transmitter will wear, but I would not expect to see the range of control reduce. Spluttery, patchy performance, yes, a worn track or wiper will do that for you.
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Buccaneer

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Re: My Boats are running Slow
« Reply #14 on: September 09, 2021, 07:32:31 pm »

Having considered all the options, again!, and with the benefit of your inputs I came back to the Transmitter as it is the only common link. I looked through the Instruction Book again and came across a re-set procedure whereby all settings are reset to factory settings. (Be careful if you ever need to use this as it also resets model names. Make some notes as you go along)


I re-set all six channels and this seems to have worked on the two boats I took out yesterday afternoon. Hopefully I can get another couple out on Sunday.


Yours
John
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