24v 120lb DIY brushless motor project

Discussion in 'Electric Propulsion' started by Catguy, Jun 7, 2017.

  1. Catguy
    Joined: Jun 2017
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    Location: St Cloud, Mn.

    Catguy New Member

    I am a new member and have purchased a 24v 120lb Caroute DIY motor for our project. The brushless feature of this motor interested me and decided to give it a try and report my findings here. The motor arrived nicely packaged in one week. The factory representative was helpful in steering me to the model selection. The motor has been opened to adapt my mounting system. I found the electronics to be nicely potted and well protected, high quality connectors, balanced rotor, NSK bearings, ball thrust bearing at the front and two propeller shaft seals with a third wiper. The post is .1" stainless. The wiring is high flex with high temp flexible insulation.The components fit with precision. To sum it up, I am impressed with this motor so far. I will add posts as the project advances IMG_2687[1].JPG IMG_2688[1].JPG IMG_2690[1].JPG IMG_2678[1].JPG IMG_2702[1].JPG
     
    Last edited: Jun 7, 2017
  2. Caroute Motor
    Joined: Jun 2016
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    Location: CN

    Caroute Motor Junior Member

    Thank you. Catguy. Looking forward more photos on your boat.
     
  3. Catguy
    Joined: Jun 2017
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    Location: St Cloud, Mn.

    Catguy New Member

    Hello all,

    Project update:

    We launched at a local lake yesterday with intentions of collecting data such as thrust, voltage, amperage, and speed. Our landing was on the east side of a three mile lake, and the wind was coming on shore with gusts over 30 mph. To make a short story longer, we boarded at the dock and went straight to full power on the motor for 1-1/2 miles into white caps, some over three feet to the protection of an island for set up. This is an 18 ft. catamaran that we are modifying for pleasure sailing. There were four souls onboard. Several waves came over the front trampoline and since our storage hatches do not have seals yet, we found our measuring equipment bobbing in the water at the bottom of the compartment so no data at this time, only opinion. We are impressed since our progress was steady and reasonable, considering as the nose would rise over a crest 96 sq. ft. of trampoline was exposed to the wind. It was difficult to measure time on this leg because we were focused on keeping the nose in the wind, hanging on and wondering if the motor could handle the load. We guessed around 30 minutes to cover this distance. (disclaimer - our estimates may have been distorted by adrenaline).

    Later in the evening the wind died and we were able to measure top speed at 5 mph. I imagined the top speed would have been higher however it seems this motor is designed for steady thrust rather than speed due to it's large diameter, flat pitch propeller. This motor is smooth throughout the full speed range and the controller works wonderfully. One quirk we found was a wobbly propeller which was corrected by shimming the propeller to shaft clearance and milling the slot for the shear pin at a slight slant.

    Attached are pics of our project including adapter cone and fiberglass spinner.

    On a personal note, this project is an incredibly fun and rewarding adventure for us and hope to collect more data soon.

    Happy sailing.
     

    Attached Files:

  4. kerosene
    Joined: Jul 2006
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    Location: finland

    kerosene Senior Member

    The under propping is to be expected. Keeps power loads lower and allows creative marketing (our 1kW matches competitions 5kW).

    Does it have temp sensor for overheating? 3d printing more reasonable prop might be realistic further down the line. 5mph for slim hulled boat is quite modest.
     
  5. Catguy
    Joined: Jun 2017
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    Location: St Cloud, Mn.

    Catguy New Member

    Yes it has internal overheat protection. May experiment with props later.
     
  6. Jed233
    Joined: May 2017
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    Location: Baker, Florida

    Jed233 Junior Member

    I just looked up that 160lb trolling motor. The specs said max RPM is 1500. That is gonna be about 5 mph even with a bigger prop. I don't know how they come up with 2100 watts being equal to 7 hp gas outboard, I get about 2.8 mechanical hp on the conversion.
     
  7. kerosene
    Joined: Jul 2006
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    Location: finland

    kerosene Senior Member

    Jed, prop rise or whether the term is (escapes me now) is what will impact the top speed. Trolling motors have low pitch blades so that their low/no speed pull force is very high compared to hp. Thus they twist the numbers and compare the lb of pull to much larger motor that has the same pull at that speed. Then they throw in nonsense about the efficiency on the electronics and the high low speed torque of the e-motor. Neither of which matter an ounce. AT low speed propeller (unless stuck by weeds) does not need high torque so its 100% mute point and the efficiencies do not matter either as the gas OB hp is taken from prop shaft.

    Prop choice is like a gear selector. E-motors are using very low gear and most gas OBs some kind of universal average. Smaller gas OBs are propped to 5-15 knot speeds. In general the high thrust models with larger and lower pitch props are better for boats that never reach 10 knots.

    E-outboards also use low pitch motors as it acts as a natural power limiter. You will never ask too high torque with the low pitch prop. With higher pitch prop you quickly get in range where you run out of power (torque) and the motor will start drawing high amps (and heat up and eat up battery capacity).
     
  8. Jed233
    Joined: May 2017
    Posts: 16
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    Location: Baker, Florida

    Jed233 Junior Member

    Yeah, I learned all that the hard way. I doubled thrust when I went to a 24 volt 86 lb thrust motor on my kayak and gained only 1 knot in speed. The trolling motor makers play hide the salami with the real amp draw and watt usage specs on their motors. I found out that 86 lb motor rated about .8 hp in real numbers. I now am working on a 24 volt, 4.5 hp 4 kw, 160 amp short tail 'mud motor' surface drive. I am going to install a small stern foil so it will plane. The surface drive will also ease the amp draw. This new motor can run on 12 or 24 volts which gives me options in different conditions. I have no intention of running around at 20 mph in a kayak but I will get 10 mph without overheating or losing too much range. The extra power will be there when I need it. I love the quiet and great speed control of emotor drives so I think it is worth building.
     
  9. Caroute Motor
    Joined: Jun 2016
    Posts: 54
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    Location: CN

    Caroute Motor Junior Member

    No temp sensor, just monitor the current. Internal overheat protection can help to decrease the current. But if the current rise too much higher in short time, it's also have burn up risk.
     
  10. Caroute Motor
    Joined: Jun 2016
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    Location: CN

    Caroute Motor Junior Member

    You know well. But 120lbs motor ratied input power is 1470W. Max shaft power is about 1083W. Even a 2 HP gas OBs can not propped to 5-15 knot speeds. 1mph speed rising, it also need double power increasing. 5-15 knot is too big range.
     
  11. Caroute Motor
    Joined: Jun 2016
    Posts: 54
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    Location: CN

    Caroute Motor Junior Member

    120lbs-24V motor for kayak can acheive about 6-7 mph speed. The speed is also depended on kayak shape and width, I mean the boat resistance.
     
  12. Caroute Motor
    Joined: Jun 2016
    Posts: 54
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    Location: CN

    Caroute Motor Junior Member

    Thank you for moving here. Any assistance, please let us know. For 3D printing props, the long pitch props may not suitbale for the motor's controler IC program.
     
  13. kerosene
    Joined: Jul 2006
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    Location: finland

    kerosene Senior Member

    First, why are you now comparing to 2hp when on amazon you comapre to 5 hp petrol ob?
    secondly, it really depends on the boat what speed range, power and prop combinations are a good fit.


    "Here are two Youtube clips - firstly using the 2hp Honda, with which I achieved a consistent 7.9 knots measured by GPS with my weight aboard, and 7.1 knots with my wife joining me (she only weighs 60kg/132lbs. The 9.8 Tohatsu gave 15.5 knots (17.8 mph or 28.6 kph) with two heavy men aboard plus gear."

    from here:
    Ross Lillistone Wooden Boats: Fleet - Videos of performance with Two Different Motors http://rosslillistonewoodenboat.blogspot.fi/2015/11/fleet-videos-of-performance-with-two.html
     
  14. Caroute Motor
    Joined: Jun 2016
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    Location: CN

    Caroute Motor Junior Member

    See the video. You have a nice boat. It's smaller and narrow boat. Electric motor was compaired with the efficiency with ob gas motor. Shaft power 2hp is 2hp, no different. But 120 electric motor can push 2000kgs boat and can achive 4 knots. How about 2HP gas motor for such big boat´╝č
     

  15. kerosene
    Joined: Jul 2006
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    Location: finland

    kerosene Senior Member

    About efficiency, "2hp Honda, with which I achieved a consistent 7.9 knot" can your 1.5 hp (or whatever the shaft power 0n 120lb motor is) achieve that?
    Efficiency is not the term for either your or my questions. I am not (nor ever have) arguing that your motor couldn't achieve high low speed thrust. I am arguing that most e-motor marketers misrepresent what it means and try to make it appear as if there was more efficiency or more power available than in a gas/petrol outboard with same output. You have done this over and over too.

    oh and btw the boat I linked to is not mine. Just used as an example of boat's role in the outcome.
     
    Last edited: Jun 21, 2017
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