How To Join 2 Batteries Together. The cable will go into a sleeve and be locked in place with set screws and the ends will twist lock into each other. Check out the diagram for more info.

The reviews of these tanks say they are great but the batteries dont last very long. A multimeter for measuring voltage and current also comes in handy. Check at a hardware or welding supply store for male and female ends for welding cables.
Normallyyou could connect the same voltage and capacity battery cells or pack in parallel.
In parallel the voltage stays the same and in series it is doubled. A multimeter for measuring voltage and current also comes in handy. This type of arrangement is used to increase capacity in this case 12v 240Ah. The plus of the first battery and the minus of the last battery are then connected to the system.

