The solenoid on your golf cart is the most used switch next to the accelerator pedal microswitch. Every time you hit your pedal, it gets clicked in. What is actually happening is a movable contact internally located inside the solenoid slams into the two stationary contacts at the top of the solenoid. Those contacts are the same ones that your heavy cables that connect your batteries and controller are wired. What this means is that the solenoid acts as a power bridge between those two destinations. So if you have upgraded your controller or motor, you will need an E-Z-GO 36-Volt Heavy Duty Solenoid to handle the load.The golf cart solenoid is just the tip of the heavy-duty iceberg. Everything needs to be upgraded on that caddie. The cables on the batteries run throughout the cart to the forward and reverse switch on series systems. Once you start demanding more power, these things are at risk. Call Buggies Unlimited and get one ordered today.