i gota 81 k5 with dual batterys, 140 amp one wire summit altanator. both batterys are mounted behind front seats with primay battery having a 72" 4 gauge battery cable goin to the starter and 10 ga. wire goin to battery. and jus the 4 kc lites goin to 2nd batt. ok, so with the 2nd battery unhooked and i turn on head lights and heater turned on hi. the volts will drop to 12 until it runs for while then it holds at 13 volts...but after running for a while with wipers and heater and headligh ts on it will drop to 12 when it idles (which make sense sense volts dropwith rpms)... and belt starts screaching.but the belts tight.....and if just heater turned on hi with nuthin else on just heater.....it will draw more then 4 kc lights....its the factory heater....same with stock headlights they will draw more then 4 kc lights.... would a thicker battery cable help this
