Project - Analysis of a practical automotive wiring circuit

Q 3 [ANS] The fuse rating from a total load of 10A from a battery will be 15A.

Q 4[ANS] This depends upon the load which is going to be consumed for a particular time.

GIVEN : load 500W , battery voltage=12v

This will require to deliver 41.66amps continuously

FOR EXAMPLE: assuming the time as 5 hrs of backup

500W multiply by 5hr=2500wh

W=V multiply by A[DC]

So its a 2500VAh

2500VAh/12V=208.33Ah

therefore for a safer side a 225 ah capacity battery is required according to me.