Work out battery cranking amps instantly with clear inputs, formula shown and shareable results.
Cranking demand scales with displacement and is much higher for diesels because of their compression ratio: roughly 230 A per litre against 160 for petrol. Cold makes it worse from both directions — the oil thickens while the battery's available current falls.
Cranking requirement
CCA required = displacement x amps per litre x cold factor
Compression ratios of 16-22:1 demand far more torque to turn over, and glow plugs draw current at the same time.
Yes, provided it fits physically and the terminals match. A higher rating gives margin and does not harm the charging system.