How To Hook Up Two Batteries In A Car. To do this you need to connect the POS terminal of the first battery to the NEG - terminal of the second battery. Do not connect a positive terminal to a negative terminal creating a seriesYou may have seen this in other situations involving batteries but this is not the appropriate setup in this case.
Think of it as comparable to adding a larger gas tank. Hence the positive terminals of both batteries go to the positive end of the series and all negative terminals to the other end of the series. A dual battery with an isolator for those who dont know is pretty much what it sounds like.
First you need space enough for a dual battery setup either in your engine bay in the cabin of your vehicle or in the tray if you have a ute.
At its most basic an automotive dual-battery system with the batteries connected in a parallel circuit essentially doubles the amount of electricity you have available. Its nothing more than a switch capable of identifying the increase in voltage generated by your cars alternator when the engine is on and then connect both batteries. For example you can connect two 6Volt 10Ah batteries together in series but you can not connect one 6V 10Ah battery with one 12V 10Ah battery. How do you hook up a battery to a car stereo.
