MOSFET design help needed.
#2
Here is a simple circuit that connects to the throttle output of the receiver (usually channel 2) and gives a digital output that was originally intended to drive LEDs for brake lights:

You can connect the output to the gate of an appropriate MOSFET to drive larger currents for motors, etc. The MOSFET must have a logic-level gate drive. The one you have shown does not. And don't forget to put a Schottky diode across the motor terminals to protect the MOSFET from voltage spikes.
Is the motor just a starter motor, or are you replacing the IC engine with the electric motor? If replacing the engine with the motor, what battery will power the vehicle? If LiPo, how will you handle the low-voltage cutoff?

You can connect the output to the gate of an appropriate MOSFET to drive larger currents for motors, etc. The MOSFET must have a logic-level gate drive. The one you have shown does not. And don't forget to put a Schottky diode across the motor terminals to protect the MOSFET from voltage spikes.
Is the motor just a starter motor, or are you replacing the IC engine with the electric motor? If replacing the engine with the motor, what battery will power the vehicle? If LiPo, how will you handle the low-voltage cutoff?
#3
Thread Starter
Tech Rookie
Joined: Dec 2016
Posts: 2
Many thanks.
I will be using my A123 2200 ma hr cells. The motor is a battery powered chainsaw one. I would like to use a Opto Isolator to drive the MOSFET gate. Should simplify gate turn on / off. Provide isolation to circuits of the receiver & servo board. I will put a load resistor across the servo motor leads to square up the gate signal.
motor specs below. Will not up load.
14 to 20 vdc
15,000 rpm 25 amp 345 watts is maximum efficiency speed.
stall current is 180 amps. in the weeds.
I will be using my A123 2200 ma hr cells. The motor is a battery powered chainsaw one. I would like to use a Opto Isolator to drive the MOSFET gate. Should simplify gate turn on / off. Provide isolation to circuits of the receiver & servo board. I will put a load resistor across the servo motor leads to square up the gate signal.
motor specs below. Will not up load.
14 to 20 vdc
15,000 rpm 25 amp 345 watts is maximum efficiency speed.
stall current is 180 amps. in the weeds.




