To wire batteries in a parallel circuit, use an insulated wire to connect a bank of batteries from positive to positive terminals and negative to negative terminals. Fasten the wire or cable from the positive terminal of one battery to the positive terminal to another battery of the same voltage and capacity. This carries the voltage and combines the amperage capacity from battery to battery. Ground this parallel circuit by connecting the negative terminals of the same batteries.
When using parallel circuits, the cables combine the capacity of the batteries while the voltage stays the same. Therefore, in correct parallel-circuited battery banks, the power load can be connected to single battery while the electrical load drains all the batteries equally. Parallel circuits can take advantage of vast banks of batteries, adding multiple batteries in sequence. Increasing the number of batteries increases the electrical capacity. The increased amperage capacity can cause wires and cables to burn or fry, so it is important to use heavily insulated wires and cables.
When connecting a series of batteries with a parallel circuit, it is useful to color code the positive and negative cables and wires to avoid connecting positive terminals to negative terminals. Mixing up these terminal wires could cause a malfunction or create a serial-parallel circuit.