Cranking performance not only depends upon the power available, but also upon the amount of load. The load of a given engine design is largely controlled by the viscosity of the engine oil. Because of these two conditions, cold cranking performance is primarily determined by the inter-relationship of a team composed of battery, cables, cranking motor, and engine oil.
To establish a better understanding of cold cranking requirements and electrical cranking system performance, the variable characteristics of each team member are discussed individually and in combination. Engine oil viscosity has the greatest individual effect on cranking system performance. The performance of the team depends not only on design of the components, but also upon their proper selection and combination. Skill in the original application to a particular engine combined with strict adherence to manufacturer's recommendations will guarantee good cranking performance throughout the life of an engine in the field.