48 amps is rather small, but you probably have other problems. Leece Neville makes a 1 wire 160 amp alternator that we used successfully for many years on our over the road trucks. Our newer ones now use a pad mount. The old are small enough to put any where and they are reasonable. 150 at a truck dealer and sometimes around 75 on eBay. We call them 1 wire but they are actually 2 so polarity can be reversed. We run a 6 gauge wire to the starter lug and another to a ground on the engine. No other wiring modifications are necessary.
