Combining the two provides the best of both worlds. Increasing both voltage and amperage.

How To Connect Your Batteries To Make Up A 24v Or 48v System
Batteries in series and parallel. A parallel configuration is not meant to. As n numbers of cells are connected in each series the emf of each series as well as the battery will be ne. How to connect lithium batteries in parallel and series. Laptop batteries commonly have four 36v li ion cells in series to achieve a nominal voltage 144v and two in parallel to boost the capacity from 2400mah to 4800mah. Connecting in parallel increases amp hour capacity only. As m number of series connected in parallel equivalent internal resistance of that series and parallel battery is nrm.
For more information on wiring in series see connecting batteries in series or our article on building battery banks. Series connection increases battery voltageparellel connection increases battery capacity. Following this example we will have two 24v 200ah blocks wired in parallel thus forming overall a 24v 400ah battery bank. Such a configuration is called 4s2p meaning four cells in series and two in parallel. Hence when charging these batteries it is important to utilize a charger that satisfies the 12 volt capacity that is necessary for both the 6 volt batteries connected in series. In contrast batteries connected in a parallel configuration are able to increase the amp hour capacity of your batteries at the same voltage.
Batteries joined together in series and parallel. Batteries that are only in parallel keep the same voltage and increase their capacity. The above diagram shows how we start to create a bank of batteries as we would use in principle on an ev electric vehicle. Batteries that are only in series keep the same capacity and increase their voltage. Video presentation about series parallel batteries. Combining the parallel connection with series connection we will double the nominal voltage and the capacity.
In other words it is series nor parallel circuit but known as series parallel circuit. The equivalent resistance of the series is nr. The basic concept is that when connecting in parallel you add the amp hour ratings of the batteries together but the voltage remains the same. For example two 6 volt batteries connected in series will deliver 12 volts of output but will carry the same amp hour capacity. Series parallel connection of batteries if we connect two pairs of two batteries in series and then connect these series connected batteries in parallel then this configuration of batteries would be called series parallel connection of batteries. Some packs may consist of a combination of series and parallel connections.
By joining two battery banks already linked in series and connecting them in parallel we increase the battery banks voltage and ampere hours.