Model Boat Mayhem

Technical, Techniques, Hints, and Tips => DC Motors (Brushed) and Speed Controllers => Topic started by: KCS on September 14, 2014, 07:03:56 pm

Title: Speed Control Input Voltage
Post by: KCS on September 14, 2014, 07:03:56 pm

  Hi all
 
I am resurrecting an old Graupner Arrow. After some experimentation in the pool (with no radio) I settled on a 9,6V battery pack to power the motor.
 
However, I now see that my speed control’s voltage input range is 4,6V to 7,4V. Is this a no go, or will it work? Will 9,6V damage the speed control?
 
Cheers
 
KC

Title: Re: Speed Control Input Voltage
Post by: Martin (Admin) on September 14, 2014, 07:32:22 pm

   O0 especially because of the current draw!

Title: Re: Speed Control Input Voltage
Post by: KCS on September 14, 2014, 07:37:11 pm

  Thanks, thought as much. I think I will make do with a lower voltage battery pack. Don’t want to cook the ESC.
 
Cheers
 
KC

Title: Re: Speed Control Input Voltage
Post by: malcolmfrary on September 14, 2014, 08:54:20 pm

In an ESC with a low voltage rating (thinking of the Hitec Gold Brick) the voltage limit was due to the resistors feeding the output transistors working right on their power limit.  More volts across them increased the current through them, whatever the load, and they heated further, cooking first their surroundings, then themselves.  Similar may well be true of other makes, or they may contain electronics that will not handle higher voltages.
If an electronic item spec gives a maximum voltage, it is always best to assume that it is a maximum, not a guide.  The only exception is where the voltage is that of a battery - it is common for an allowance to have been made by the designer for a fully charged battery, but not for an extra cell or two.