this is a bit of a long shot but here goes.
I need to buy a speed controller for an electric ride on car and I've had no success in finding one with a reverse polarity switch and one that also accepts a hall sensor as a throttle, they all come with potentiometers which are useless to me.
So, I know i can use a DPDT relay or a switch to change polarity but as there'll be currents in excess of 20a going through the relay at times, i don't want that relay near my son's gear shift, in case it fails under load.
My thinking is to have the motor connected to the relay/switch to take the brunt of the current and control the relay/switch with the gear shift that is a DPDT on,off,on switch. Is this possible? I just can't figure out how I would wire up the switch to the motor connected relay/switch to control it...any ideas?