Re: Alternator and battery question?
1553<br />Hard to follow your wireing. If I understand, then all three negitive wires are tied together and also have wire to the engine block.<br /><br />Starting positive has a red to the starter solenoid and a orange to the alternator output post.<br /><br />Two batteries you call parallel have the positive post tied together and one has a black wire that run to the same alternator output post as the starting battery orange wire.<br /><br />If this is correct then all 3 batteries are wired in parallel and you batteries are only as good as the weakest battery.<br /><br />One way you could test this is with the motor off take sll three positive batteries cables off. Lay them on a block of wood or carboard so they will not short out. Now with a meter connect the ground (black wire of meter)to the engine block or one of the negitive battery posts. Connect the red meter wire to one of the posts of the parallel batteries. Meter should read zero volts. Now connect the positive post of the starting battery and check the meter. If it now reads 12 volts then all three batteries are in parallel.<br /><br />If you do not have a meter then you could do the same thing by turning on the radio. If the radio plays when you connect the starting battery postive post then they are all in parallel.<br /><br />I would start by at least changing the black wire from your alternator to your parallel batteries postive post to a RED wire.<br /><br />Wired that way any device left on will run down all 3 batteries. A dead cell in any battery will also discharge the other two.<br /><br />I would install a battery isolator and isolate all three batteries.