How to check the number of parallel and string power supplies in the battery cabinet

Multiple interconnected batteries are called a battery bank. When batteries are connected in series, the voltage increases. When batteries are connected in parallel, the capacity increases. When batteries are connected in series/parallel, both the voltage and the capacity increase. Single battery. Two batteries in series. Two batteries in parallel.

Lithium battery in series: the voltage is added, the capacity remains the same, and the internal resistance increases. Lithium batteries in parallel: the voltage remains the same, the capacity is added, the internal resistance is reduced, and the power supply time is extended.

Lithium battery pack 48V20AH generally single lithium battery is 3.5V, so 48V lithium battery pack needs 48/3.5=13.7, just take 14 in series. If the manufacturer has provided a set of 12V lithium batteries, then 4 can be connected in series. As long as the output voltage is 48V, the current is 2A or 4A.

Paralleling strings together greatly increases the complexity of managing the battery pack and should be avoided unless there is a specific reason to use this configuration. In this setup, each string must essentially be treated as its own battery pack for a variety of reasons. In a below example, 2 strings of 8 cells each are placed in parallel.

Lithium batteries in parallel: the voltage remains the same, the capacity is added, the internal resistance is reduced, and the power supply time is extended. Lithium battery series and parallel: There are both parallel and series combinations in the middle of the battery pack, which increases the voltage and increases the capacity.

The maximum is at around 3 (or 4) paralleled strings. The reason for this is that with a large battery bank like this, it becomes tricky to create a balanced battery bank. In a large series/parallel battery bank, an imbalance is created because of wiring variations and slight differences in battery internal resistance.