---
title: DC Battery Systems
…341 unchanged lines
label: Duty Cycle Duration
type: select
+drawing_ref: true
options:
- "1 hour (typical attended substation)"
- "4 hours"
- "8 hours (typical unattended substation)"
- "24 hours (remote / isolated site)"
− - "Site-specific — see drawings"
default: "8 hours (typical unattended substation)"
```
…642 unchanged lines
## A spare cell that has been allowed to sit on the shelf for years without freshening is not a spare; it is a failed cell that the Owner does not yet know is failed. {note}