AMPs question

[Kwacker]

What sort of AMPs run through the battery cable to the engine when it running?

I'm in the process of moving the battery to the boot and want to make sure I get the right size battery cable.

Thanks

Kwacker

[Poledriver]

Very little when running, it's on starting that max current is drawn. If moving battery from front to back you should really increase cable size by 50% cross-sectional area. Maybe someone can come on here with an actual figure for current drawn?

[red griff roger]

As a clue, there is (sometimes) a 100A fuse. It is a big current

[The AJP Griff]

There are a few variables that affect how many amps a cable can safely carry,and these need to be take into consideration when choosing the cable size.The length of the cable and the ambient temperature it lives in will have the greatest affects,so where you choose to route it will make a difference.Please dont just buy 100A cable as it's higher rated than the fuse,the fuse normally lives between the alternator and the starter motor,and has no place on the circuit which carries the highest load,that which runs from the battery to the starter.You need to allow for when load increases,such as a cold battery producing lower volts,or continual cranking in hot weather and the cable is hot(high resistance).Big is beautiful when it comes to cable selection,and as long as it fits well then the bigger the better.
Whilst i could probably get away with 40mm csa cable on mine when i put my battery in the boot,i'll be looking at using 55/60mm csa if i can.

The usual disclaimers apply here.