Electrical Best Practices Page |1 Contents Scope ........................................................................................................................................................................................................................... 9 Common Electrical Problems ...................................................................................................................................................................................... 10 GENERAL INFORMATION ........................................................................................................................................................................................ 10 FAILURE MODES ..................................................................................................................................................................................................... 10 Short Circuit ........................................................................................................................................................................................................ 10 Open Circuit........................................................................................................................................................................................................ 10 Intermittent Circuit ............................................................................................................................................................................................. 11 Sources of Electrical Problems ............................................................................................................................................................................ 12 OEM and Auxiliary Battery Guidelines ........................................................................................................................................................................ 17 OEM BATTERY GUIDELINES ..................................................................................................................................................................................... 17 General Information ........................................................................................................................................................................................... 17 Discharge Prevention .......................................................................................................................................................................................... 18 Charging Procedures ........................................................................................................................................................................................... 19 OEM BATTERY RELOCATION GUIDELINES ............................................................................................................................................................ 20 Location .............................................................................................................................................................................................................. 20 Vibration: ........................................................................................................................................................................................................... 20 Accessibility ........................................................................................................................................................................................................ 20 Tilt Angles ........................................................................................................................................................................................................... 21 Temperature ...................................................................................................................................................................................................... 21 AUXILIARY BATTERY GUIDELINES ............................................................................................................................................................................ 21 General Information ........................................................................................................................................................................................... 21 Location .............................................................................................................................................................................................................. 21 Venting ............................................................................................................................................................................................................... 22 Mounting and Fastening ..................................................................................................................................................................................... 22 Connecting and Grounding ................................................................................................................................................................................. 22 Best Practices – Electrical 2018 Revised Date: 09/30/2017 Electrical Best Practices Page |2 Cable Sizing......................................................................................................................................................................................................... 22 BATTERY DISCHARGE LIMITER GUIDELINES ......................................................................................................................................................... 23 Electrical System Interfacing – New Circuit Guidelines ................................................................................................................................................ 25 NEW CIRCUIT GUIDELINES .................................................................................................................................................................................. 25 Interfacing to the OEM Electrical System ............................................................................................................................................................ 25 Body Builder Junction Block/Connector .............................................................................................................................................................. 26 EXTENDING OEM CIRCUIT GUIDELINES ............................................................................................................................................................... 26 Electrical System Interfacing – Design Guidelines........................................................................................................................................................ 28 Design Guidelines ................................................................................................................................................................................................... 28 Cable (Wire) Selection Guidelines ....................................................................................................................................................................... 28 Cable Ampacity ................................................................................................................................................................................................... 28 Design Recommendations .................................................................................................................................................................................. 28 Cable (Wire) Types.................................................................................................................................................................................................. 29 • Passenger compartment .................................................................................................................................................................................. 29 • Engine compartment ....................................................................................................................................................................................... 29 Typical Calculation Example ................................................................................................................................................................................ 32 WIRE HARNESS ASSEMBLY GUIDELINES .................................................................................................................................................................. 33 Design Recommendations .................................................................................................................................................................................. 33 CONNECTING GUIDELINES ...................................................................................................................................................................................... 33 Design Recommendations .................................................................................................................................................................................. 33 CONNECTOR TYPES ................................................................................................................................................................................................