Installation and Operation
10
900-00264-01-001 Rev A
Figure 8
Series/Parallel String Configurations
Load Bus –
Load Bus +
Load Bus –
Load Bus +
Batteries are placed in both series and parallel for both additive voltage and amp-hour capacity.
Series strings placed in parallel have the same nominal voltage as each string. They have the same
amp-hour capacity of each string added together. Two parallel strings of two NorthStar NSB
BLUE+ batteries in series have a nominal voltage of 24 Vdc, twice the nominal voltage. They also have
double the amp-hour capacity of a single battery. Two parallel strings of four batteries in series have a
nominal voltage of 48 Vdc at double the amp-hour capacity of a single battery.
In a series-parallel bank, it is not recommended to connect the load to the positive and negative
terminals of a single string. Due to cable resistance, this will tend to put more wear on that string.
Instead, it is recommended to use “reverse-return” or “cross-corner” wiring, where the positive cable is
connected to the first string and the negative is connected to the last. This will allow current to flow
evenly among all strings.
