Model Boat Mayhem
Technical, Techniques, Hints, and Tips => Batteries & Chargers => Topic started by: 17-09 on April 21, 2025, 11:01:19 am
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Hi ,
Just a quick one, would a Torpedo 850 motor be OK on a pair of NimH 7.2V batts wired in series?
The motor is 12volts and I'm asking it to run on 14.4 or more if fully charged.
It is in an original heavy 46inch crash tender currently on 2x 6v lead acids in series.
Many thanks
Alan 17-09
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Have to say probably not but if it's in give it a try. Nothing to lose except an old motor but keep the prop size sensible to keep the current manageable
Good luck alan
Phil
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Using MFA's original data , it says the operating voltage is 6v -12v , with a current draw of 10.6 amps at 8977 RPM for maximum efficiency , which I reckon gives an input power of 127 watts . I therefore suggest you may find some form of cooling beneficial .
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Personally I would look at changing the motor the 850 are power hungry and with the batteries you are using I would be surprised if the boat came up onto the plane, and the run time would be short.
Just a thought :-)
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Depends on how serious you are but a brushless motor on a boat like this would be far more efficient and powerful but you would need an an appropriate speed control. I'm sure that other members can suggest a suitable combination.
Colin
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Hi
I am running a 50mm 450kv brushless motor on 6S Lipo(twin 3S) setup each side of the rudder.
A 50mm 2blade prop which on noload 10150rpm.
120Amp car esc.
Proformance is spot on with very good turning circle.
Harry
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Hi to both Phils, Colin and other mayhemers.
I think you are all correct, I was hoping for a quick fix but I knew deep down that I would eventually need to go brushless, the model
which I got second hand was fitted with a diesel I/C engine which I changed for a 800 which moved water about but did not get on the plane, this I changed again for a Torpedo 850 [size=78%]which improved things however I thought lightening the boat by using NimH's or Lipos would be about right. [/size]
Thanks again guy's
Alan....
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Hi 17-09
I am just about to start to build the Vintage Model Works 46 inch Crash Tender. They recommend a Tornado Thumper V2-4260 from Overlander.
Turnigy Aerodrive SK3-4250v outrunner from Hobbyking.
Personally i am going with an Overlander Thumper T4250/06 which gives the same power ic 60 according to Nexus Models.
for the ESC i will be using a Hobbyking 120 AMP Seaking on 4s Li-Pos.
Hope thiis helps i am new to brushless motors i have always used iv engines.
Regards madboats
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Run it on a 11.1v lipo, borrow one first, see how it goes.