Apr 17, 2012, 03:25 AM
Registered User
Romania
Joined Dec 2006
41 Posts
Quote:
 Originally Posted by wparsons Practical output wattage = V * I * E, you don't need to know anything about resistance, etc. V = voltage I = current E = efficiency. Input wattage is simply V * I.
I do not think this formula is correct.
This formula would result E ; E= P /V*I
This means that if I lower the supply, increase efficiency .... that contradicts the laws of physics.
 Apr 17, 2012, 04:01 AM Registered User United States, HI, Honolulu Joined Dec 2002 356 Posts I am by no means an expert, but I think since efficiency is always less than 1 (that is 100%), the above formula should be consedered OK. input wattage Pin=Uin * Iin output wattage Pout=Uin * Iin * efficiency (which is <1) so P out is always less than P in.
Apr 17, 2012, 09:29 PM
Registered User
Joined Aug 2008
9,214 Posts
Quote:
 Originally Posted by OldMann I do not think this formula is correct. This formula would result E ; E= P /V*I This means that if I lower the supply, increase efficiency .... that contradicts the laws of physics.
Input Wattage = Voltage * Current.

Output Wattage = Voltage * Current * Efficiency or Output Wattage = Input Wattage * Efficiency

Rearranging that gives:

Efficiency = Output Wattage / (Voltage * Current) or Efficiency = Output Wattage / Input Wattage which is 100% correct.

Not sure what you mean about lowering supply and increase efficiency or contradicting the laws of physics, all the above is definitely correct as far as physics is concerned.
 Apr 18, 2012, 08:57 AM United we race ! Slovenija, Ljubljana Joined Oct 2006 121 Posts Iīm still confused, about this discussion on efficiency. Max 75A on 11S is correct data (3025W). Lowering the voltage increases current, so I think on 6S (120-160Amp)? I think itīs like that isnīt it? Thanx to all comments. Kruno
Apr 18, 2012, 08:59 AM
United we race !
Slovenija, Ljubljana
Joined Oct 2006
121 Posts
Quote:
 Originally Posted by renosa Pulsar how you ar going to cool this motors? they are not water cooled!
For coolin, I wil made something like this:

http://www.hobbyking.com/hobbyking/s...ount_30mm.html

or using this:
http://www.hobbyking.com/hobbyking/s...75MM_BOAT.html
Apr 18, 2012, 04:52 PM
Registered User
United States, HI, Honolulu
Joined Dec 2002
356 Posts
I use the T600 turnigy motors, 1400KV on 6S and I use the cooling plates in your 2nd link. They work good!
The ourtunners are torque monsters!!!

Here is the first test run of the boat:
 Lithium (1 min 32 sec)
Apr 18, 2012, 09:51 PM
Registered User
Joined Aug 2008
9,214 Posts
Quote:
 Originally Posted by pulsar Iīm still confused, about this discussion on efficiency. Max 75A on 11S is correct data (3025W). Lowering the voltage increases current, so I think on 6S (120-160Amp)? I think itīs like that isnīt it? Thanx to all comments. Kruno
If you lower the voltage without changing anything else, current draw will actually go down (opposite goes if you increase voltage but change nothing else). If you want to keep the same wattage output you would have to prop up to increase load (and amp draw).
Last edited by wparsons; Apr 19, 2012 at 04:53 PM.
 Apr 19, 2012, 01:50 PM Registered User Joined Apr 2012 5 Posts send me again plase.
Apr 19, 2012, 09:59 PM
Registered User
United States, VA
Joined Aug 2011
38 Posts
Quote:
 Originally Posted by pulsar And this I hope you all know what it is. I have obut 20 models that I draw myself. If someone need something, contact me I see what I can do.
pulsar, your work is very impressive and your generousity is unparalleled. Myself and many others might be interested in this model below. Do you happen to have a design of the Outerlimits SV43?

Specs: http://www.outerlimitspowerboats.com/43SV.htm
FE model: http://www.e-powerboat.de/archives/515
Profile pics: http://i62.photobucket.com/albums/h9...hipmodlow4.jpg
Very good scratch built: http://www.offshore-rc.com/forum/ind...howtopic=25587
 May 03, 2012, 05:01 AM Registered User Joined Apr 2012 5 Posts hi; Send me Mystic C5000R autocad dxf data plaese. Hakanisik26@hotmail.com
 May 03, 2012, 05:04 AM Registered User Joined Apr 2012 5 Posts Mystic C5000R 3d autocad data hello my name is hakan send me Mystic C5000R 3D autocad data, plaese hakanisik26@hotmail.com
 May 03, 2012, 05:21 AM Registered User Joined Apr 2012 5 Posts send Mystic C5000R again plase send again plase
 May 03, 2012, 08:43 AM United we race ! Slovenija, Ljubljana Joined Oct 2006 121 Posts Hi. Ok here is the 3D file of mystic c5000r V2.
 May 04, 2012, 01:13 AM Registered User Joined Apr 2012 5 Posts tanks a lot of
 May 04, 2012, 03:28 PM Registered User Joined Mar 2012 15 Posts Hi, check your pms. I need plans for the hrp mono. Please reply!