# Battery string

Canonical URL: https://eloragrid.ai/symbols/battery-string
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: BS
Drawing use: SLD, Schematic
Reference families: IEC, IEEE / ANSI

A series connection of cells or modules reaching the system DC voltage, often with its own fuse or breaker and monitoring.

## In plain English

### What does Battery string mean?

A battery string is a group of cells or modules connected in series to reach the operating DC voltage of an inverter, UPS or DC system. Several strings may run in parallel to increase capacity, and each string normally has its own protective device and disconnect so that one string can be isolated without shutting down the others.

### A simple example

Drawings show the battery symbol with the cell or module count annotated, a dashed line indicating omitted cells, and the string fuse or breaker at the positive and sometimes negative terminal. String current sensors and the battery management connections are often drawn at the same point.

### What the drawings help you do

The symbol does not state how strings share current or what happens when one string has a weak cell. Parallel strings of different ages or states of health share current unevenly, which the drawing alone cannot reveal.

### This particular reference

A series connection of cells or modules reaching the system DC voltage, often with its own fuse or breaker and monitoring. A string is one series chain; a battery bank or rack may contain several strings in parallel.

### Terms

- DC: Direct current: electricity flowing in one direction.
- Terminal: An identified point where a conductor connects.
- Signal: Electrical information passed between devices, rather than necessarily the main power supply.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [xStorage battery energy storage system](https://www.eaton.com/us/en-us/catalog/energy-storage/xstorage-battery-energy-storage-system.html)
- [IEC graphical symbols for diagrams](https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/)


## What it represents

A battery string is a group of cells or modules connected in series to reach the operating DC voltage of an inverter, UPS or DC system. Several strings may run in parallel to increase capacity, and each string normally has its own protective device and disconnect so that one string can be isolated without shutting down the others.
Drawings show the battery symbol with the cell or module count annotated, a dashed line indicating omitted cells, and the string fuse or breaker at the positive and sometimes negative terminal. String current sensors and the battery management connections are often drawn at the same point.
The symbol does not state how strings share current or what happens when one string has a weak cell. Parallel strings of different ages or states of health share current unevenly, which the drawing alone cannot reveal.

## How to read it

- Read the annotated number of cells or modules in series.
- Each parallel string should have its own isolation and protection.

## Information to show or reference

- State cells or modules in series and nominal string voltage.
- Show string fuse or breaker and disconnect.
- Reference string current measurement.

## Important distinction

A string is one series chain; a battery bank or rack may contain several strings in parallel.

## Facts

- Connection: Series
- Protection: Per-string fuse or breaker
- Annotation: Cells or modules in series
- Preview: Independent educational illustration; consult the applicable standard and project legend for the exact graphic

## Public references

- [xStorage battery energy storage system](https://www.eaton.com/us/en-us/catalog/energy-storage/xstorage-battery-energy-storage-system.html) — Eaton. Public battery energy storage system context including string arrangements.
- [IEC graphical symbols for diagrams](https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/) — IEC. IEC graphical symbol context for batteries.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.