Series or Parallel
When batteries are connected in series, their voltages are added together. This makes them appropriate for applications that need more power. In contrast, when batteries are connected in parallel, their capacities (measured in amp-hours) are added together. This means that two 12V 30Ah batteries in parallel would give you a total capacity of 60 amp hours. The total voltage doesn’t change.
What is an amp hour?
An amp-hour is a unit of electrical charge that measures the amount of electrical energy that can be stored in a battery. It is commonly used to describe the capacity of a battery. For example, a 100Ah battery can supply 100 amps for one hour or 1 amp for 100 hours.