SLEEP mode is a reduced functionality state that can be optionally used to reduce power dissipation when there is little or no system load current or charging in progress, but still provides voltage at the battery pack terminals to keep the system alive. At initial power up, the Settings:Configuration:Power Config[SLEEP] bit determines whether the device is allowed to enter SLEEP mode. After initialization, SLEEP mode can be allowed or disallowed using the 0x0099 SLEEP_ENABLE() and 0x009A SLEEP_DISABLE() subcommands. The 0x12 Battery Status()[SLEEP] bit indicates whether the device is presently in SLEEP mode or not. The 0x62 Alarm Status()[SLEEP] and 0x62 Alarm Status()[WAKE] bits can be used to generate an interrupt to the host when the device operating state changes between SLEEP and NORMAL modes.

When the magnitude of the 0x3C CC1 Current() measurement falls below a programmable current threshold given by Power:Sleep:Sleep Current, the system is considered in relax mode, and the device autonomously transitions into SLEEP mode, if settings permit. During SLEEP mode, comparator-based protections operate the same as during NORMAL mode. ADC-based current, voltage, and temperature measurements are taken every Power:Sleep:Voltage Time seconds. When the device is configured such that 0x3C CC1 Current() is not available, the device uses the current wake detector to decide when to enter and exit SLEEP mode using the Power:Sleep:Wake Comparator Current setting.

The device exits SLEEP mode if a protection alert occurs or significant current is detected, or the 0x009A SLEEP_DISABLE() subcommand is sent. The current is checked by the current wake detector approximately every 2.44 ms and, if it exceeds Power:Sleep:Wake Comparator Current in magnitude, the device transitions back to NORMAL mode. When exiting based on current flow, the device first runs a SLEEP mode measurement cycle, then restarts the NORMAL mode measurement loop.

The device also includes a 10-second hysteresis on the SLEEP mode entrance, in order to avoid the device quickly entering and exiting SLEEP mode based on a dynamic load. After transitioning from SLEEP mode to NORMAL mode, the device does not enter SLEEP mode again for 10 seconds.