Controller Essentials: PreCharge Resistor

Ever produced a large spark when connecting your battery to the controller?  Not only is it a bit startling, it has the potential to ruin your day (and your controller).  Pre-Charge Resistors are usually required by most controller manufacturers to ease the power into the controller rather than shock the system with full voltage & amperage.  Simply attach it between the controller & positive battery lead for 3-5 seconds, remove, then make your connection.  Doing so will supply the mosfets with a small amount of power to not shock the system.  Batteries equipped with a Smart BMS, soft start function accomplish the same feat (if you utilize it).

Purpose & Benefits