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Author Topic: M.F.A Volts ?  (Read 1245 times)

john54

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M.F.A Volts ?
« on: June 17, 2008, 05:18:45 PM »

Hi All
Does anyone out there know if a mech speed controler (12v 850 motor ) would be o.k running on 14.4v ?
Useing 12v s.l.a and just about planes  :(
Dont need warp speed have boats for that (see pics)
Just want her running nice
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Martin [Admin]

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Re: M.F.A Volts ?
« Reply #1 on: June 17, 2008, 05:39:58 PM »


Should be but you need to be careful between 3/4 & full throttle where the current
is at it highest - at full throttle, the speed controller usually bypasses the resistors or windinding.
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Robert Davies

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Re: M.F.A Volts ?
« Reply #2 on: June 17, 2008, 08:22:08 PM »


Volts are not the issue, amps are.

The weak points of the MFA mechanical speed controllers tend to be where the main wiring connects to the resistor wiring. With enough current the solder blob melts and unsolders itself. The gotcha is that this happens underneath the board so you can't see it happening!

-Rob
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FullLeatherJacket

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Re: M.F.A Volts ?
« Reply #3 on: June 17, 2008, 11:40:45 PM »

Check out the L in SLA. It stands for Lead. There's also an L in Planing and another in Useless.
Buy NiMH cells and save the SLA for a battleship.
FLJ (Oops! Another L..........)
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malcolmfrary

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Re: M.F.A Volts ?
« Reply #4 on: June 18, 2008, 12:23:09 PM »

The 12v in this case is an indicator of the nominal battery voltage.  A fully charged 12v battery will be actually higher, so an actual 14.4 is near enough. 
Mechanical controllers need to be closely matched to their motors - if the motor draws a lower current than expected, there is no fine low speed control, if higher, then nothing happens until almost full throttle, when it all happens at once.  Plus, if the current is above the upper limit of the controller, bits start to melt.
ESCs have the advantage.
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