It is very important to choose the right size Solenoid for the golf cart speed controller you are going to use.
Your solenoid is what lets voltage or current go from batteries to the speed controller. Most are activated when you press the foot peddle, a microswitch lets voltage onto the small bolts of the solenoid. The 2 small bolts are the coil, this is what makes solenoids 12v, 36v , or 48v etc referred to as coil voltage.
When proper voltage is applied to the coil the magnet moves inside causing contacts to touch in the solenoid and letting power flow from one large post to the other.
If you use voltage under what the solenoid coil is rated you might not have enough voltage to keep the contacts touching and will result in losing power off and on to your cart.
If you use over the rated voltage of the coil you can burn the coil wiring and might cause the solenoid contacts to stick together which will not turn off current flow when you let off the foot peddle.
What about the diode across the 2 small post? YES YOU NEED ONE !!
This is a reversing diode or blocking diode. It only lets voltage flow one way. When the solenoid is cut off, (letting foot peddle up) the magnet loses its magentic field which causes a voltage spike. This spike could damage the controller or other components in you golf cart. The diode dissipates the energy Most diodes are stripped, The Stripped end goes to the + Positive side when installing.
Now the 2 Large Post. this is were the voltage and higher amps flow through. All current for your speed controller and motor flow through the solenoid. So you need one rated high enough to handle the amps you are using. You need the correct braking current and carrry current rating.
When larger controllers are used, the continuous current and breaking current are very important to keep the voltage stable and clean to the controller. It also has to break the large current should a motor or controller fail. You want to be overrated when choosing a Solenoid.
You will find many different solenoids available, but not all are equal. Whats inside really matters, some are copper some are silver plated.
So what about the pre-charge resistor, do I need it also? YES !
It goes between your 2 large post.
When the solenoid is closing the pre-chargre resistor minimizes the voltage across the solenoids 2 big post, which reduces arcing, it also pre-charges the capacitors in the controller which can help extend the life of component.
The right size or gauge of your wiring is just important. The wiring needs to be able to handle the current flow and this also helps with heat.
If you have any questions our staff can help you with the correct size solenoids, motors, speed controller, wiring and F&R switches for your application.
For Educational purpose only please refer to manufacturer recommended rated components.