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anthony_marquart

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Long history with nitro boats. First electric. Bought a UL19.
running 6s, stock prop, yeah I know.
never even pulled full throttle. Cool down pass after every kinda fast run.

ran one battery pack. Either heat or low battery restriction came on the esc. It limped in. No big deal. Motor and esc were hot to touch. Not burning. Could hold finger on them for 3-4 seconds.
Let it cool and changed batteries, which were just warm and brand new.
Adjusted batteries a little further back and pulled the turn fin up a bit.
Returned to the water. Boat was faster. Still never squeezed the trigger all the way. 2 passes and the motor stopped all at once.
Got the boat in within 5 min. Motor warm, esc a little warmer. Not hot. Rudder still working. Motor not working at all. Not locked or feeling any different than before. Light on esc is out. Probably ran 10% of second battery packs.

any suggestions?
 

longballlumber

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Sounds like you burnt up a motor.... 2000kv on 25v (6S lipo) is not advised. Especially, if your using the same propeller as run on 4S. Typically, when an FE motor "burns up" they will still turn. it's the coating on the motor windings that degrade and ultimately cause a short.

IMO, this is all extremely poor advise if suggested by Horizon.

Do you have another motor that you can confirm the controller power FET's weren't taken out in the process? It's a positive sign the servo was still working
 

longballlumber

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Additionally, running FE boats on partial throttle can be particularly hard on the ESC. They are far more efficient and produce less heat when ran at full throttle. This is why its important to keep props small in high RPM setups, and "sneak" up in size.
 

anthony_marquart

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I have no other FE parts except batteries. The manual says to run 6s w stock prop u need to do cool down passes between fast passes. That’s what I did.
Is there a direct replacement motor that would do well on 6s? Would the light on the ESC go out with dead motor?

Other than this crap, this is a pretty cool boat for a RTR.
 

longballlumber

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Like I said poor advise by Horizon....

Not sure about the light on or off with the controller.

If it's just going to be a fun boat any motor in the 36mm-40mm can diameter and 56mm-72mm length will work. IMO its less about motor diameter/length as it is the correct KV for the voltage that you intend on running then the correct prop.

I would suggest a KV of 1200-1500 for 6S. However, I will say the boat size lends itself to more of a 4S boat.

OSE has a wide variety of motors to choose from. RC Boats by Offshore Electrics
 

Grimracer

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Dec 27, 2001
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part throttle removes more cowls on FE boats.. LOL your lucky it did not do it on yours!

Grim
 

anthony_marquart

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Well guys I’m learning! So run close to flat out or just enough to stay on plane? Maybe I missed a meeting, but what do you mean “removes more cowl”?
Nice to talk Talk with u guys again.

it was fast for a minute!
 

anthony_marquart

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So probably that first run w a lot of mid to low throttle passes overheated the motor and or esc. Is that what we suspect? Going nitro to electric is like being a newby all over again.
 

anthony_marquart

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Ok I just have to ask a question. I’ve been thinking about this “hotter running at mid throttle than full” thing. Trying to understand this. The only thing I can figure is the components get as hot at mid as they do at full throttle. But they get a lot less water flow. And then over heat. Is that why?
 

Steve White

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Current draw is consistent, at partial throttle the heat dissipation in the controller is extreme because of the voltage drop across it. Volts x amps = watts. So at partial throttle = more watts into the controller.
 

longballlumber

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Regardless of Full Throttle or Partial Throttle...... 6S on 2000kv is TOO MUCH. THAT is your root cause. I don't care what horizon says. As a matter of fact, I would contact them and see what they say. You followed their instructions and you burnt something up.

One major difference between FE and IC is the lack of instant feedback. If an IC boat isn't right i.e. boat set up, prop (load), motor issues, or all of the above; you're going to get instant feedback. It won't run or it will die when you throw it in.

With an FE boat you don't get instant feedback and may times you don't get feedback until it's too late (after a run). If the boat isn't happy i.e. running wet (setup), too much prop (load) it's going to show itself in the form of heat. Heat can start to degrade components. Sometimes in 30sec or over the course of several runs.

There is a misconception about FE that it can be "easy" or "plug-n-play" AND go REALLY fast all at the same time.... FE CAN be very stable and reliable, but that requires conservative set-ups. unfortunately, those setups don't typically wet the appetite of most boaters (racers or rec boaters). The faster you want to go; the higher the risk of burning stuff up.
 

longballlumber

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Current draw is consistent, at partial throttle the heat dissipation in the controller is extreme because of the voltage drop across it. Volts x amps = watts. So at partial throttle = more watts into the controller.
Sorry Steve, but I don't agree with your comment.

Current (amp) Draw is dependent on load (AKA prop) and is not consistent while running a boat. If your load is consistent then your current will be consistent.... Generally speaking more prop (pitch, diameter, or both) will be more load. Less prop (pitch, diameter, or both) less load. Not to mention starting an FE boat from standstill in the water is MUCH more current than when it gets on plane and is running in a straight line. As your prop comes in and out of the water; you will get current (amp) draw spikes. You will have less current in the straights than you will in the turns. Again, generally speaking.

My very simplistic explanation of controllers - Controllers contain FETS. FETS, are "switches". as you pull the throttle the switches start turning on and off (opening and closing). Full throttle is always open. partial throttle they are turning on and off (opening and closing) very slowly. Now, what doesn't change is the input voltage (battery). While those switches are closed they still see your input voltage. In-turn this generates heat in the controller. Again, this is a very basic explanation.
 

Samuel Hagan JR

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We run our UL19 on 4S for 3 years and no issues. Haven’t replaced a motor yet or a ESC.
 

Steve White

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Sorry Steve, but I don't agree with your comment.

Current (amp) Draw is dependent on load (AKA prop) and is not consistent while running a boat. If your load is consistent then your current will be consistent.... Generally speaking more prop (pitch, diameter, or both) will be more load. Less prop (pitch, diameter, or both) less load. Not to mention starting an FE boat from standstill in the water is MUCH more current than when it gets on plane and is running in a straight line. As your prop comes in and out of the water; you will get current (amp) draw spikes. You will have less current in the straights than you will in the turns. Again, generally speaking.

My very simplistic explanation of controllers - Controllers contain FETS. FETS, are "switches". as you pull the throttle the switches start turning on and off (opening and closing). Full throttle is always open. partial throttle they are turning on and off (opening and closing) very slowly. Now, what doesn't change is the input voltage (battery). While those switches are closed they still see your input voltage. In-turn this generates heat in the controller. Again, this is a very basic explanation.
I was up at the 10,000' level bro. Of course load varies with prop which is directly tied to current draw and a host of other variables.

Given one understands the basics, consider my comment - moving the throttle position on the transmitter causes current to flow from the battery, through the controller and motor. Battery voltage output is essentially constant (yes if we want to split hairs and deal with internal resistance, the changes thereof with heat -vs- load then the battery isn't constant) so at a partial throttle or less than full speed setting the controller takes a beating. The worst case operating region for the controller will be somewhere between 50% on up to near 100% - where at 100% the controller gets a break from the power/heat dissipation levels.

I stand firmly by my comment that moving the throttle position from somewhere around 50% on up, the current draw will be fairly consistent in the circuit as the boat comes up onto plane and from there approaches full speed AND power dissipation in the controller is brutal at lower speed settings in a race setup. Somewhere around 75% power level is where the controller will take the most beating.

Simple electronics physics. Thanks for your comments.
 
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Grimracer

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Dec 27, 2001
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8,454
It might help to think of it this way..

At part throttle the power from the batteries needs to go someplace.
At full throttle its battery's to motor.
At part throttle its battery's to controller to motor.

In the end 6S is WAY to much.. when I was developing that stuff It was a CONSTANT market push to **** out a 6S boat WITH the equipment we had.. NOPE.. was not a real popular answer.. Horizon CAVED bigly!

Grim
 

rhomodel

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Jul 15, 2003
Messages
293
6S 2000kv is about 25 volts fully charged @2000 rpm= 50 k rpm.
If that will not fry the engine, also running half throttle, as the others said, is a major stressing thing on the regulator.
4S and 2000kv should be plenty, and I would not run a lot of half or semi throttle. Unless you are after records there should not be a need to have cooling stretches, especially not for a RTR boat, that should about tho be bomb proof.
Out of curiosity: what is the rating of the esc in terms of max V and A?

And the remark hoods popping: By product of overheating is hydrogen production. Combined with enough heat or a spark ( I know is brushless, but if things get hot enough they ignate, and plop there goes the hood...
 
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