what thickness cable is ok for battery relocation

[cully]

IF you relocating the battery on a diesel id go for 35mm to reduce the cranking voltdrop as the ecu wont like it and throw wobblies
also use the same 35mm on the earth straps from the battery to the shell

diesels are real hard on batterys when cranking from cold

if its a petrol then 25mm minimum this is all core size not measured outside sheath diameter