Solar energy needs to be stored and the larger the solar system, the larger the battery capacity needs to be. The largest leisure / deep-cycle batteries available on the market today are 250-300Ah and this may not be enough for your system. If this is the case, we need to connect a number of batteries together to create a battery bank with a greater collective capacity. We may also want to change the system voltage from 12V to 24V or 48V; this could be because we want to use 24V devices or because we want to reduce power loss by increasing the system voltage. To calculate the size of the battery bank you require, please visit our advice page: Battery Bank Size Calculations.
There are various ways that you may choose to wire together a number of batteries in order to create a battery bank to suit your requirements. As a general rule, connecting batteries 'in series' (i.e. +ve to -ve to +ve to -ve) adds the voltages together, but the Ah capacity remains the same; connecting batteries 'in parallel' (i.e. -ve to -ve and +ve to +ve) combines the capacities, but leaves the voltage unchanged.