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ESC Help

Old 09-26-2010, 06:49 PM
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stevemic
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Default ESC Help

ok i have 2 esc's, i would like to know if they can be water cooled and used in a boat application.. anyone ever used one of these in a boat??? thank you so much for any help.
Old 09-27-2010, 03:12 PM
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Default RE: ESC Help

They can be used in a boat with a motor, battery & prop that will ..NOT... pull more amps than the ESC is rated for.

Just do not get the ESC,s guts wet.

ESC,s do not care what they are put into.
Old 09-27-2010, 04:51 PM
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Default RE: ESC Help

Very cool, ive run big gas boats for a few years, this is first EP build. thank you
Old 09-30-2010, 07:30 AM
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pompebled
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Default RE: ESC Help

Hi syog100,

As Cyclops2 said, ESC don't mind where they are put in, as long as the requirements stay within the specs.

Having said that 60A isn't a lot for a fast electric, so watercooling might be a good idea.
The cheap Chinese ESC's have the nasty habit of being poorly manufactured; sometimes less than 30% of the fets has physical contact with the heatsink, trying to power something that draws around 40 A will usually make such an ESC go poof...
As an example one of my 100A Mystery with the heatsink off:

The dark patches are the spots where the fets touched the heatsink.

I sand the fets flat and add a watercooler like this one:

Made out of 6 mm aluminum, drilled with 3,2 mm.

I use a heat transfer compound between the fets and the cooler and add a new piece of shrinkwrap.

A before and after picture:


Regards, Jan.
Old 09-30-2010, 08:15 AM
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Default RE: ESC Help

Thanks im luvn all the info. ok, this is what i got, tell me if it will work lol i just bought a r2 hobbies 32 cat, it has a inrunner 1880kv. will the mystery 60 amp esc be a good choice ( i got it cause it was cheap) and i would like to run lipo's, the boat has a tray for just 1 battery. is this a good start or no lol yhank you guys so much..
Old 09-30-2010, 11:35 AM
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pompebled
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Default RE: ESC Help

Hi syog100,

I assume you got this cat?
http://r2hobbies.com/eng/proddetail....bt0402001_code

I run the R2hobbies Arowana, which has the same motor, I get about 6-7 minutes runtime with a 5000mAh 4S1P 25C Lipo.

I use a 100A watercooled Mystery ESC, which gets warm after a full six minute run.
As the max motor current is 47A, which it will draw getting out of the hole, probably close to double that amount, I doubt if a 60A ESC, properly watercooled will cope...

As all RTR boats (there's no such thing as ready to run! At best the boat is assembled at the factory, often not very good either...) the cat needs to be checked for leaks, all bolts tightened and secured with Loctite, the drive train lubed and alligned.
Don't assume the Chinese did this for you, do it yourself!

If you want to run two packs, put them in the sponsons with Velcro and connect them in series, if you use two 2S packs, or in parallel if you use two 4S packs.
Getting the weight down from the tunnel is good for the CoG and improves the handling.

Regards, Jan.
Old 09-30-2010, 12:00 PM
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Default RE: ESC Help

YEP thats the one... so i guess i should have gotten a 100 or more esc? oh im not racing it, just using on a semi small lake. the lake is just big enough for a proboatsv27 ep. so i would be happy with that kinda speed or close to it for now.
Old 09-30-2010, 01:43 PM
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pompebled
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Default RE: ESC Help

Hi syog100,

Our moderately set-up Arowana's run 65+ km/h (40+ mph), with a faster motor, or a 5-6S Lipo 50 mph is possible.

As a cat generates lift, it will run faster than our monohulls, but needs to make wide turns at speed, so watch out on your 'semi small lake', you may run out of water fast.

Regards, Jan.
Old 09-30-2010, 03:21 PM
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Default RE: ESC Help

so i should get an esc rated higher than 100 amps?? ill be running lipos
Old 09-30-2010, 04:11 PM
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pompebled
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Default RE: ESC Help

Yes,

A watercooled 100A ESC is sufficient for the 1880KV motor.

Short leads between the Lipo('s) and the ESC are also important.

Regards, Jan.
Old 09-30-2010, 04:30 PM
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Default RE: ESC Help



ok cool, I cant thank you enough for the info and taken the time to answer my questions..THANK YOU i might bug ya again if needed lol

Old 10-02-2010, 03:47 AM
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pompebled
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Default RE: ESC Help

Bug away, that's what a forum is about.

Regards, Jan.
Old 10-02-2010, 04:45 AM
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Default RE: ESC Help



LOL

Old 11-10-2010, 09:32 AM
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Default RE: ESC Help

Just received my 100 amp mystery esc, Was kinda sorta thinking of using 2 cooling plates 1 on each side, like sandwiched in-or would that just be a waste. figured it would keep it cooler.
Old 11-10-2010, 11:51 AM
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pompebled
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Default RE: ESC Help

Hi syog100,

I added a picture of the Mystery ESC without the shrinkwrap and the cooling plate; as you can see there are two PCB's with the powerfets and on the underside of the bottom one is the processor unit.

It's rather pointless to cool that side as there's very little to cool...

If you want to go overboard on the watercooling, it's possible to separate the two PCB's and rebuild the ESC with a cooling plate between the two (which consists of a brass plate with water tubing soldered onto the sides outside the PCB).

For the motor at hand this elaborate cooling is overkill, and very labour intensive aswel, I once added double cooling plates to a 100A Mystery, it worked very well, for about a year, until the ESC got wet (poof...).

I have some pictures of how I did that, let me know if you want to try that and I'll upload them.
Wait, there must be an old topic called 'watercooling a Mystery ESC', try the search function, the pictures should be there.
Found it:
http://www.rcuniverse.com/forum/m_79...tm.htm#7948096

Regards, Jan.
Old 11-10-2010, 12:18 PM
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stevemic
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Default RE: ESC Help

Very cool thank you, I am cooling the motor and esc separetly so they each have there own cooling. can u direct me to a better prop? not sure what to use. dont wanna use the stock. again thank you
Old 11-10-2010, 05:15 PM
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pompebled
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Default RE: ESC Help

Hi syog100,

Usually having seperate cooling lines for the ESC and the motor isn't really necessary, but it doesn't hurt either...

The water that runs through the ESC first only gets a bit warmer, so the motor gets plenty of cooling, at least in our 31,5" Arowana set-ups.

As the occasional prop breaks running in competition, I usually run Graupner K-series props, they are carbon fibre reinforced and much stiffer than the plastic stock props that come with the boat.

Start with a 42K and work your way up, 45K usually is the limit, you'll know when the motor won't rev out at speed and things get hot inside; lipo, ESC, motor.

Once youve found the best carbon propsize you could replace that with a similar metal one, more expensive, but more efficient too.
Most do need sharpening and balancing, so you'll have another craft to learn...

Regards, Jan.
Old 11-12-2010, 09:03 AM
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stevemic
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Default RE: ESC Help



OH you gotta help me on a prop lol I dont wanna use the stock, lol. I'm not going to use 2 cooling plates, but i allready put in seperate cooling lines. just looking for the right size water pickup, was thinking of getting the water pickup for the traxxas villian EX,looks like a good size for my transom. also using the rudder pickup.


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