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Old Jan 29, 2013, 06:58 AM
*Miss Geigo*
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Large Brushless DC Motor Suggestion

Hello Boaters

please need suggestions about a large dc motor that can pull a

Vee Hull
-280 cm length
-120 cm beam
-200 Kg Weight
and having a speed of 35 mile

thank you very much ! I'll bring some pictures for the hull soon .
Regards
Jad
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Old Jan 29, 2013, 01:57 PM
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At that weight you'll probably be much better off with a gas engine, that's about the size of a seadoo.
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Old Jan 29, 2013, 04:38 PM
*Miss Geigo*
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Originally Posted by wparsons View Post
At that weight you'll probably be much better off with a gas engine, that's about the size of a seadoo.
Wparsons my friend the idea is using a complete rc system instead of a gas engine
I'm studying the problem for now running a small boat on dc motor
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Old Jan 29, 2013, 07:52 PM
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You can still have a complete RC system when using a gas motor.
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Old Jan 29, 2013, 09:27 PM
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It all depends on what voltage you intend to run as to which KV rating is suitable.

This might be enough. 12,000w. Available in various Kv ratings.

http://shop.rcboatbitz.com.au/index....ort=20a&page=4

Then there's this one perhaps. 23,000w, if you've got deep pockets.

http://shop.rcboatbitz.com.au/index....oducts_id=1057
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Old Jan 30, 2013, 08:00 AM
*Miss Geigo*
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Quote:
Originally Posted by wparsons View Post
You can still have a complete RC system when using a gas motor.
I want to run the boat on electric system only .

Quote:
Originally Posted by 785boats View Post
785boats
ohh god the 23,000w need input voltage between 33 and 170 v from where should I bring all this voltage ! :O
I'm thinking about running the boat on 36~48V and any suitable KV

Question !
can I ran this kind of motor on a Boliden battery 100 A ?or above
or just lipo is required ?

Thank you guys
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Old Jan 30, 2013, 12:29 PM
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If you want 12000w on 48v you would be drawing 250a constant, if you wanted 23000w on 36v you would need 640a constant.

If you want to run relatively lower voltage, you will need a lot more amperage to get the wattage needed to make the boat move.

23000w is only 30hp, is that enough to move a boat that size/weight at the speed you want?
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Old Jan 30, 2013, 01:09 PM
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Old Jan 30, 2013, 02:55 PM
*Miss Geigo*
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Quote:
Originally Posted by wparsons View Post
If you want 12000w on 48v you would be drawing 250a constant, if you wanted 23000w on 36v you would need 640a constant.

If you want to run relatively lower voltage, you will need a lot more amperage to get the wattage needed to make the boat move.

23000w is only 30hp, is that enough to move a boat that size/weight at the speed you want?
wow that's really a big number of Amps ! in this case I need a power plant for my boat :P

yeah 30 hp is my purpose but I'm still thinking if this motor is able to move the boat , but I'm afraid of the drawing A :/
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Old Jan 31, 2013, 09:48 AM
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It's roughly 765 watts per HP, and volts * amps gives you watts. If you know how much hp you need, then you can calculate the watts, volts and amps needed. Keep in mind that my calculations assumed the motor is 100% efficient, which it won't be.

If you want to keep the amp draw around 100a you would need 230v+ to get 30hp.
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Old Jan 31, 2013, 02:49 PM
*Miss Geigo*
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Quote:
Originally Posted by wparsons View Post
It's roughly 765 watts per HP, and volts * amps gives you watts. If you know how much hp you need, then you can calculate the watts, volts and amps needed. Keep in mind that my calculations assumed the motor is 100% efficient, which it won't be.

If you want to keep the amp draw around 100a you would need 230v+ to get 30hp.
wow !!!! it's impossible to get 230v+ !
any way thank you wparsons for your help I really think that the gasoline motor is 100% successful for that hull then the dc motor
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Old Jan 31, 2013, 08:07 PM
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Motorcycle engine DD -say a 250cc should do it. Ninja 250R makes 30HP@10500 rpm. 2blade 5.5Dx6P would be a good start for speed. Do a search for Ron Hill he designs and makes race props and can make to suite rpm / hp at the prop to reach 30mph.
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Old Feb 03, 2013, 08:16 AM
*Miss Geigo*
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Originally Posted by Amp Abuser View Post
Motorcycle engine DD -say a 250cc should do it. Ninja 250R makes 30HP@10500 rpm. 2blade 5.5Dx6P would be a good start for speed. Do a search for Ron Hill he designs and makes race props and can make to suite rpm / hp at the prop to reach 30mph.
thank you for your suggestion
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