I just bought a clamp meter, and I am testing it on our 1990s Starex, is it better to use the clamp on the positive battery cable or the negative battery cable? What is the desirable milliamp range for a normal battery drain? Thank you.

As of now the findings of my test found that my battery is discharging 1.2 amps on the negative terminal cable. Do you think I have to look for a electrician to find where is the culprit?