I agree with Slartibartfast.. also some place will let you go in the yard with your vehicle ...so you could also operate the grinder with the inverter pluged on your car/truck... this way you don't have to go around with a 30+ lbs battery and grinder etc...
on another note, Slartibartfast, do you know if such a body repair manual exists for the R50 platform (2001-2004) ? (Sorry to highjack the thread , but this 1990 repair book has some pretty good procedures in it... I would love to get my hands on the R50 version...(if it exists)...
S.