Yes you should be using 5mm but na ho toh go for two 2.5mm for each terminal because starter take very high current. Also battery ke negative me isliye nhi lgate kyonki jab hum connect disconnect krte hai tab spark niklte hai which not safe as battery emits hydrogen gas
@@scienceperspective8999i tried to help one guy with 2 sqmm wire it didn't work mechanic came and he have big cable heavy it started in one second. First i checked with small wire so i thought it's self motor and alternator all gone . mechanic said wire should be strong. Which wire will you suggest to keep in car
