As has already been said, a good set of clamps works every time. Friend of mine usta have a surplus store on the outskirts of town (he closed about 10 years ago and I still miss him). He sold mostly new and used metal, but also lots of other stuff. He went to many of the government-surplus auctions in the SE and would come home with some 'finds'. One time he had several thousand feet of cable (00 iirc)....which I think had been used as welder leads on one of the TVA dams. I bought enough to replace the leads on the welder and make 5 or 6....long.....sets of booster cables; a set for the shop, one for each truck, etc. I think the clamps I put on 'em were 1600 amp. I'm long retired and have a newer pickup, but I'm sure I'll have my old 1st generation-Cummins one-ton dually when I die; it'll be 20 years old this Valentine's day. I special ordered it from the dealer and remember the day it came. The booster cables I keep in it are behind the seat and have clamps only on one end.