What is a zero cracking power?

Answer 1

ZERO CRANKING POWER: It was the first cold weather rating and is applicable in relation to crafts which ply in freezing weather.This-degree performance test gives a valuable insight into battery quality.Large batteries are tested at a 300 A drain with battery chilled to -18 C (0 F) whereas smaller sizes are tested at half this value.This test consist of two part (a) the battery is first chilled to - 18 C (0 F) and the load applied for 5 second.Mean while,the voltage output is recorded.It is first part of zero-cranking power rating.(b)The test is continued further till voltage drops to 5 V.The number of minutes it takes to reduce the voltage to 5 V forms the second half of the rating.Higher both the digits,better the battery quality.