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Old Dec 28, 2011, 06:47 PM
Busted_wing is offline
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Seaking 180 Rpm Limit?


Last summer I bought a Ul-1, it came with a swordfish 70 a esc, and a Castle Creations Vertigo 3424-1800KV (500 class heli outrunner) with the stock size prop. I took it out and ran it on a 5s 5000Mah Li-po (what I happened to have) The thing was wicked fast, way faster than my stock Supervee27. Everything came back slightly warm so I figured I had a good setup. Next run out I got the esc wet, apparently not waterproof so it was fried. As it was starting to get cold in MN I ordered up a Seaking 180A esc and 2x3s 5000 Mah batteries, wired everything up and took it out on the cold a$$ lake. the batteries were fully charged and in series 6s 5000mah. It was very slow, I'd have to guess maybe 20mph. Does anyone have any guesses why? Does a Seaking 180 have an rpm limit which is being made worse by the motor having so many poles as outrunners tend to have? Help please. Thanks!
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Old Dec 28, 2011, 07:54 PM
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The Seaking (aka Turnigy & Hobby Wing) 180 is a pretty good all around esc and will handle high rpms). The default timing should have been close for an outrunner but it may need some programming to run properly with your motor.
You might try it on 5s as you did with the other esc and see if the motor doesn't like the extra voltage. And there's always the possibility that maybe you had the packs in parallel instead of series. (a photo of the wiring would be useful in determining that)
Also, if the boat has been sitting idle for some time you may want to check for any binding or excess drag in the driveline.
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Old Dec 28, 2011, 09:35 PM
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If it's really cold, the batteries might have been too cold to deliver any useful current.

I had that happen with my tear into when it was around the freezing mark, but it runs great in warmer weather.
Old Dec 29, 2011, 12:14 AM
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The default timing on the seeking 180 is 15 degrees and should be good for a 12 or 14 pole outrunner . You can always bump it up if you want , but I would double ck. the way you wired the packs ? You might have them in parallel , that would explain the difference in speed .
Old Dec 29, 2011, 12:34 PM
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Sounds like the problem of hitting the LVC early. A lot of people report this with these Seaking & Turnigy 180 ESC's. Mine did it too. It's an internal software or firmware problem that some of the ESC's have, apparently.
Or you did not set the throttle range on the ESC with your TX as per the instructions. This is very important with these ESC's. Try that first & test it on the water.
There's a couple of checks you can do to see if it is the LVC problem.
Firstly, manually set the voltage to 6s. Don't use the auto setting. Also set the cutout to 3.2V/cell. Test it on the water.
If the problem is still there, set the cutouts to 2.8v/cell. Test it on the water.
If the problem is still there, switch OFF the LVC. But make sure the input voltage is still set at 6s. Test it again.
Always make sure you set the input voltage to whatever voltage pack you are running.

If the problem is still there then it's not the throttle range or LVC problem, and like others have said most likely a battery or connection problem.

Hope this helps a bit.
Paul.
Old Dec 31, 2011, 12:35 PM
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I was able to find a better spec sheet here on hobbyking. http://www.hobbyking.com/hobbyking/s..._Boat_ESC.html

That says -Fast clock cycle MCU combined with efficient code means 100,000rpm cpu cycle* Well I asked one of my electrical engineers at work what that means exactly and the way he explained it: Every time a magnetic pole passes a set of windings inside the motor the esc has to reverse its electrical polarity in order to keep repelling that magnet. My castle out runner has at least 12 different magnets in it, meaning that the esc must go through 12 cpu cycles just to make one revolution of the motor. Assuming 12 magnets this would limit my top rpm to 8330 rpm, way too slow for a boat...

The moral of the story... The turnigy/seaking 180 while an awesome esc... Is not well suited for use with most outrunners, and should really be used with 2 or 4 pole inrunners, even a 4 pole motor will top out at 25000 rpm with this esc.
Old Dec 31, 2011, 06:15 PM
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Well... with that electrical engineer backing you I'd say you pretty much have this under control then to your satisfaction then.
I think you'll find quite a few FE boaters that would argue the 25k figure as the max it will spin a 4 pole motor though.
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Old Jan 01, 2012, 09:26 AM
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Quote:
Originally Posted by Busted_wing View Post
I was able to find a better spec sheet here on hobbyking. http://www.hobbyking.com/hobbyking/s..._Boat_ESC.html

That says -Fast clock cycle MCU combined with efficient code means 100,000rpm cpu cycle* Well I asked one of my electrical engineers at work what that means exactly and the way he explained it: Every time a magnetic pole passes a set of windings inside the motor the esc has to reverse its electrical polarity in order to keep repelling that magnet. My castle out runner has at least 12 different magnets in it, meaning that the esc must go through 12 cpu cycles just to make one revolution of the motor. Assuming 12 magnets this would limit my top rpm to 8330 rpm, way too slow for a boat...

The moral of the story... The turnigy/seaking 180 while an awesome esc... Is not well suited for use with most outrunners, and should really be used with 2 or 4 pole inrunners, even a 4 pole motor will top out at 25000 rpm with this esc.
Just a heads up, 12 magnets does not mean 12 poles. Poles is determined by winding and the polarity swapping of the magents. You could easily make a 2 pole outrunner with 12 magnets. It's very hard to determine the number of poles a motor has by feel.

I agree with Bill though, there's lots of people running these ESC's with 4+ pole motors to well above 25k rpm.
Old Jan 01, 2012, 01:04 PM
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Quote:
Originally Posted by Busted_wing View Post
I was able to find a better spec sheet here on hobbyking. http://www.hobbyking.com/hobbyking/s..._Boat_ESC.html

That says -Fast clock cycle MCU combined with efficient code means 100,000rpm cpu cycle* Well I asked one of my electrical engineers at work what that means exactly and the way he explained it: Every time a magnetic pole passes a set of windings inside the motor the esc has to reverse its electrical polarity in order to keep repelling that magnet. My castle out runner has at least 12 different magnets in it, meaning that the esc must go through 12 cpu cycles just to make one revolution of the motor. Assuming 12 magnets this would limit my top rpm to 8330 rpm, way too slow for a boat...

The moral of the story... The turnigy/seaking 180 while an awesome esc... Is not well suited for use with most outrunners, and should really be used with 2 or 4 pole inrunners, even a 4 pole motor will top out at 25000 rpm with this esc.
This must be wrong as I have hit 40,000 rpm win my 6pole outrunner and SK 180.

I say its a LVC problem caused by either cold batteries, bad batteries, too high of a lvc setting. Data loggers are invaluable in helping you find it.
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Old Jan 01, 2012, 01:06 PM
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Quote:
Originally Posted by Busted_wing View Post
Last summer I bought a Ul-1, it came with a swordfish 70 a esc, and a Castle Creations Vertigo 3424-1800KV (500 class heli outrunner) with the stock size prop. I took it out and ran it on a 5s 5000Mah Li-po (what I happened to have) The thing was wicked fast, way faster than my stock Supervee27. Everything came back slightly warm so I figured I had a good setup. Next run out I got the esc wet, apparently not waterproof so it was fried. As it was starting to get cold in MN I ordered up a Seaking 180A esc and 2x3s 5000 Mah batteries, wired everything up and took it out on the cold a$$ lake. the batteries were fully charged and in series 6s 5000mah. It was very slow, I'd have to guess maybe 20mph. Does anyone have any guesses why? Does a Seaking 180 have an rpm limit which is being made worse by the motor having so many poles as outrunners tend to have? Help please. Thanks!
What batteries exactly?
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Old Jan 02, 2012, 12:31 AM
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It is the temperature effecting you performance. The same thing happen to me last week. Temps right around 34-36 degrees in the water and outside right at 35. The batteries were to cold to perform the necesary amps therefore it goes into soft cut in my boat. The water temperature was keeping the motor and esc and batteriesto cold to work. I run a 4074 1400kv on a sk 180 on 6s 40c 4400's in my geico and run mid 50's all day. But that day 45 max and the boat shut down twice because it couldnt get the amps. Two days later temps were back up and water temp was 45 and ran 56 and 58mph. So i know it makes a difference. Also when water is cold the drag on it is little more too.
Old Jan 02, 2012, 09:25 PM
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I keep my batteries insulated and warm until I am ready to run them, that helps. Keep my hatch tape in my pocket as well.
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Old Jan 19, 2012, 04:16 PM
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Quote:
Originally Posted by Busted_wing View Post
That says -Fast clock cycle MCU combined with efficient code means 100,000rpm cpu cycle* Well I asked one of my electrical engineers at work what that means exactly and the way he explained it: Every time a magnetic pole passes a set of windings inside the motor the esc has to reverse its electrical polarity in order to keep repelling that magnet. My castle out runner has at least 12 different magnets in it, meaning that the esc must go through 12 cpu cycles just to make one revolution of the motor. Assuming 12 magnets this would limit my top rpm to 8330 rpm, way too slow for a boat...

The moral of the story... The turnigy/seaking 180 while an awesome esc... Is not well suited for use with most outrunners, and should really be used with 2 or 4 pole inrunners, even a 4 pole motor will top out at 25000 rpm with this esc.
I have a feeling its a typo on the spec sheet now that I think about it more.

100000 cycles per minute is ~1667hz, or 1.7mhz. Most modern ECU's operate at 5000hz + range, which would be 3000000 cycles per minute.
Old Jan 20, 2012, 08:28 AM
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Most are currently at 240,000.


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