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Thread: total electric package

  1. #1
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    Default total electric package

    Setting up a new boat, 36 in 1/10 scale dumas hydro, with sss 3660 3 phase brushless motor, ESC 150A, 4S, 42000mAH, ran two batteries in parallel, ran it a little on test run, seemed to get a little hot, so have been working on a better cooling system. Am I going in the right direction with this hardware? Should I run batteries in series? Size of batteries OK? A lot I do not know about what questions to ask for help.

  2. #2
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    Mar 2011
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    Not in series. You want them in parallel. Both postives(red) married to one another and both negatives(black) married to one another then into ESC.

    Series would be positive from one battery to negative of second battery then the remaining loose red/black to ESC.

    I just reread, you got that part. What size prop are you running? Flex cable or straight shaft? If you have a flex then you should have a gap between the strut and the drive dog of propeller
    Shawn

  3. #3
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    Not in series. That would double the input voltage, and likely kill your ESC.
    Sometimes, the fittings can be a constraint on cooling flow, and so can sharp bends in the cooling line.
    Cheetah, Super Rio, (Mod) Starship (Mod and sold),

  4. #4
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    When you say a little hot, how hot? For some 120°F is hot while for others 120°F is normal. What prop are you using. . .size, two or three blade? Have you tried different props and if you have, still a little hot? As for your battery questions it's been answered but to clarify so you have a better underestanding. . .you are currently running two 4S 4200mah in parallel which gives you 4S 8400mah which will give you same voltage of 4S but double the capacity. . .result will give you longer run time which is fine. If you run it in series two 4S 4200mah this will give you double the voltage to 8S but capacity remains 4200mah. . .in your setup the result is bad, "POOF". . . no no no.

  5. #5
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    Aug 2018
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    So I also ran 3s lipo batteries , in series in the boat, seemed to run all right. Maybe it was not to hot, I could hold my finger on cooling coil for a while. Is my ESC 150 amps the right size? I think I did burn one up, I just replaced it. Will check on size of props and let you know. We have two boats the same size, have been moving things around so lost track of the problems.

  6. #6
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    Apr 2007
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    OP, to diagnose your issue we need to know:

    Exactly what motor Kv?

    Exactly what prop?

    Exactly long did you run?

    Exactly how did you run - full throttle all the time, mostly part throttle?

    Is the hydro running light on the water, plowing, what?



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  7. #7
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    Aug 2018
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    WA
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    Motor is SSS Brushless, 3660/2726KV, 150A ESC we have two boats,, Boat 1, straight shaft with Propeller # 448, 2 blade 48mmX 1.4 pitch, lipo 4 Cells 2 batteries in parallel, Boat No. 2, flex shaft Grim racer Prop 42X55, two three cell lipo batteries in series, Boats got a three minute run, very speeds, hydro up on steps, looked OK, on both boats after short run it seamed that the ESC cut out altogether, then re started with on and off motor running, then just stopped dead, . Have installed new 150A ESC's and up graded the water cooling systems on both boats. Is it that easy to burn out the ESC? How do we check them out to see if they are toast. Before we hit the water again, we want to make sure we have the right set up.

  8. #8
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    Well at 2700 KV that is really only a 3s setup. So two 3s packs in series is 6s. Way too much for the ESC. 4s with the 448 prop would be too much prop too. Really I don’t think a 3660 motor will turn that prop.

    So really you should try 3s and like 42mm props. Perhaps Jay will chime in here with more experience.

  9. #9
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    Mar 2017
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    VI
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    Like the guy said a 2700kv motor is a 3s motor. A 42mm prop on 3s sounds suitable.

    And to get 3 minutes runtime with a 448 on 4s and and 4255 on 6s you had a lot of runtime. Those setups are easily over 200 to 250amps on a 150amp ESC.

  10. #10
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    The Dumas kits make large, very heavy boats and those SSS motors are simply not appropriate. Who recommended that motor to the OP? They did him no favors there and cost him a lot of $$$. Too, 3S is simply not enough power for these hulls.

    If he is not formally racing the boats there are several ways to go. Running 4S with a 40x82/1500 Kv motor and an x447 (preferred) or x448 prop should work with that ESC and give decent performance, although changing to a flex drive would help a lot too. Or on 6S a 40x82/1100 Kv motor with the same prop will give similar performance at a lower amp draw. I doubt that the boats were running constantly on step for three minutes, it is very easy to over estimate run time without a timer.

    One could go with higher power, higher amp setups for more speed, at the cost of less run time and a better ESC. Regardless, these hulls will be limited in what they can do.


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  11. #11
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    Aug 2018
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    WA
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    Fluid: Boat No.1, Last run 10 20 2018, what a day, boat ran great with a little problem, later about that. To re-cap, dumas hydro 36in. weight full load 7.5lbs., 3660/2726kV, brushless, 3s lipo 5200mah, two in parallel, 150 A ESC, 42/55 prop. Ran 3-5 minutes, what a thrill SO it stopped, puller it out of water motor very hot, even after 10 minutes. battery lead to ESC had to pry apart with screwdriver, one lead from motor to ESC discolored joined and burnt. I plan to change cooling on motor from coils to water jacket what else do I need to look at. Boat No 2 never hit the water, after moving parts around and checking out, found motor will run a little very slow slow. this boat also has a new ESC as above are our amps too high? should we change to a 36/? motor that will turn at 1800 to cut down the heat, have looked at the ones at OE, thanks for the help still on the learning curve. Puget Sound Bob.

  12. #12
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    Oct 2015
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    Ca
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    Take note of Fluids post above. His advice is spot on. That is way too small and too hot of a motor for a boat that size. A couple of years ago I converted a Dumas Pay n Pack 32" hydro to electric power. With a leopard 4082 1600kv motor and it ran pretty good on 5s. What size connectors are you running? They should be a minimum of 5.5 mm. You also mention cooling coils, are you talking about the kind that use soft copper tubing to wrap around the motor? They are about 98% useless. I stopped using them in the early 90's because they just don't work. Keep us posted on your progress. I know the boat you are running and would like to see how it works out for you.

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