dont bother with it....

good idea but its just going to be a reliability risk

if its only 30amp forget it

and like was said if you want it in your dash you essentially need to run all the cars power from battery to dash and then distribute to everything from their

an inductive ammeter is potential a much better prospect in theory but i havent actually seen one of them

but then my multimeter has an induction loop and that works well.... so there it is... get an induction one or forget it