When charging batteries in parallel it is common to have batteries fail sooner than anticipated. This is largely in part because the batteries are simply connected as instructed: positive to positive and negati. In typical installations, the batteries are connected side-by-side (negative to negative, and positive to positive), starting with the first battery connected to the second, and so o. The easiest method to achieve better 'Balanced Charging' is to rewire one set of leads (positive or negative) so it is connected to the opposite end of the battery bank; se. Figure 4 below shows a perfectly balanced charging system. Please note that the image is a little misleading as the negative lead was routed below the battery bank to not cover up or c. Connecting or charging batteries in series is done to increase the output of your batteries nominal voltage rating. To do this you need to connect the POS (+) terminal of the first batter.