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Old Mar 12, 2011, 10:14 AM
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Thanks guys, I'll look into it.
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Old Mar 12, 2011, 10:20 AM
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I'm running the same 35a ESC with a 28mm 3200kv outrunner on 3s, and have had zero issues with current draw. I definitely don't pick up speed between 3/4 and WOT, just more noise. If I built another one I would drop to a 2800kv motor, but not because of current draw just because the extra revs don't do any good in this boat.

I had it out for a test run today (shredded the impeller, so I turned down a 30mm prop). I got about 5-6 minutes of blasting around the river (lots of WOT) and only took about 700mah out of the 2200mah pack.

I do have a cooling issue though, haven't figured it if it's a blockage or if the lines are just too small with too small of a radius on the curves between the ESC and motor.

Another thing to keep in mind with the motors is that almost all (except the 2040 3600kv motor I suggested) have a 3mm shaft, which will mean drilling out the stock coupler on the motor end. I did it easily with a cordless drill and vice grips, but if you aren't comfortable with that then you should really look at a motor with a ~2mm shaft.
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Old Mar 12, 2011, 10:30 AM
eak
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I would not do that because it's to close to the limit of the esc. The mosfets will burn up after a while.
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Old Mar 12, 2011, 10:53 AM
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Hmmm, do you have lots of water flow before the water gets to the cooling jackets?

Maybe you don't have enough of the pick up in the jet unit.
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Old Mar 12, 2011, 10:56 AM
eak
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running an electronic device over it's rating is never good.
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Old Mar 12, 2011, 11:09 AM
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Quote:
Originally Posted by eak View Post
running an electronic device over it's rating is never good.
Whats this in response to?
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Old Mar 12, 2011, 11:12 AM
eak
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to that. "I'm running the same 35a ESC with a 28mm 3200kv outrunner on 3s"
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Old Mar 12, 2011, 11:43 AM
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Mod thread

I forgot something. The escs mostly come out with 35 1000 caps which don't disapate heat well. I took a SS and took the caps off and replaced the with 5-35 470 caps to disapate heat faster due to size of caps ( 470 ) and stayed with the 20% over or under the orignal 2000UF total. My 5-470 =350 and 20% is 400. The main concern is if all the fets are touching the cooling plate, if not, you have to sand the fets so all touch and use Artic Ice as thermal paste btween the 2.
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Old Mar 12, 2011, 11:48 AM
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I wish Spektrum would come out with telemetry in their marine receivers so we could monitor the motor and esc. I guess you could run a car receiver, but its not recommended for what ever reason.

If heat is an issues i may install some kind of little fan on the esc water jacket, or go with a bigger one i guess.

Anyone running dual water pickups? One for esc, one for motor...
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Old Mar 12, 2011, 12:10 PM
eak
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Get a zigbee and a atmega168 or something and a heat sensor. code your own telemetry system with a lcd display on land with a tweeter on it or something.
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Old Mar 12, 2011, 12:11 PM
eak
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you can make it realy advanced with gyro chips and connect the mcu to a servo to controol trim planes and whatever
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Old Mar 12, 2011, 12:15 PM
eak
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Or you can go realy crazy. Add a gps chip. and make a failsafe that overides the reciver making the boat run back to land by it self if out of range.
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Old Mar 12, 2011, 01:58 PM
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I'm running a 24x45mm 3200kv water cooled inrunner on 3S with that 35A esc. Pulled the setup out of my brushless mini deep vee which I have had for over a year. That thing has submarined a few times with the throttle stuck on and the ESC is still good. That was swinging a 30mm metal prop, so I don't think amp draw should be a problem with the 19mm impeller.
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Old Mar 12, 2011, 02:25 PM
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Wow, I'm glad there is guys like eak out there that crunch numbers as all I ever find myself doing is running these damn things! LOL... Plop it in, hope for the best. Of course having a general idea as to what works helps but ya.

Thanks to guys like you man, adding to this thread with figures is sweet! Keep it up.
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Old Mar 12, 2011, 05:55 PM
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Quote:
Originally Posted by eak View Post
to that. "I'm running the same 35a ESC with a 28mm 3200kv outrunner on 3s"
If you look at the current draw after ~6 minutes of WOT running, you'll see I'm drawing far below 35a.

700mah in 6 minutes is nowhere near 20a, nevermind 35a.

A 19mm jet drive isn't really a ton of load on a 450 outrunner. I could run it without water cooling at all for river bashing, I only have it so if I'm blasting around at WOT it doesn't get too hot.
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