Specifications

Smart Battery Charger Specification
SBS Implementers Forum -Page 6- Revision 1.1
than a Level 2 charger. In some cases, a system designer may choose to use the system host to
communicate with both the Smart Battery and a Level 2 Smart Battery Charger to provide a hybrid Level 3
functionality.
4.3. Interface Definition
The interface is separated into two types: normal communications that are either Smart Battery-to-Smart
Battery Charger or Smart Battery Charger-to-Smart Battery, and critical communications that are
exclusively Smart Battery-to-Smart Battery Charger. None of the communications require the system’s
Host take any action to control charging.
4.3.1. Typical Communications between a Smart Battery-and-Smart Battery Charger
Communication between the Smart Battery and the Smart Battery Charger may be initiated by either the
battery or the charger depending upon the specific implementation, but the same minimum set of
information is exchanged between the battery and the charger, regardless of which device initiated the
transaction. For example, a Level 3 Smart Battery Charger may poll the battery periodically to determine
the appropriate charge voltage and current, while a Level 2 charger must wait for the battery to initiate the
data transmission. In both cases, data (charging voltage and current) is supplied by the battery to the
charger.
Smart Battery to Smart Battery Charger communications are performed:
• To allow the Smart Battery to instruct the Smart Battery Charger to set the appropriate charge current
and charge voltage.
• To allow access to the "correct" charge algorithm for the battery.
• To allow Smart Batteries to be charged as rapidly and as safely as possible.
• To allow new and different battery technologies to be used in existing equipment.
4.3.2. Critical Communications from a Smart Battery to the Smart Battery Charger
A Smart Battery must have the ability to inform the Smart Battery Charger of potentially dangerous
conditions. These notifications represent a critical effort on the part of the battery to inform the Smart
Battery Charger and System Host that the battery is being overcharged. The Smart Battery expects the
Smart Battery Charger and/or the System Host to take the appropriate corrective action.
Smart Battery-to-Smart Battery Charger or System Host communications are performed:
• To allow the Smart Battery to instruct the Smart Battery Charger to discontinue charging due to:
♦ over charge
♦ end of normal charge
♦ over temperature.
• To allow the Smart Battery to instruct the Smart Battery Charger to restart charging when:
♦ the battery alarm conditions have returned to normal
♦ an end of discharge cycle has occurred during battery conditioning.