SBDS – Addendum For Fuel Cell Systems
Release 1.02 April 11, 2007
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
Revision History:
Revision Changes 1.0 Initial Release
1.01 Correction to Auto_Soft-OFF(2Bh) function [Section 5.2.7] Release for voting
1.02 Removed Xpress-Px-Data(24h) as a result of review telecon held on
2/13/2007. This is because the existing ManufacturerData(23h) is able to duplicate the proposed Xpress-Px-Data(24h) function.
The command codes for those commands following 24h have all changed command codes to remove the break in sequence.
Date 8/29/06 1/1907 4/11/07
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
Table of Contents
1.
INTRODUCTION
1.1.
Scope
2. REFERENCES 3. DEFINITIONS
4.
FUEL CELL SYSTEM OVERVIEW
4.1.
Smart Battery or Fuel Cell System Software Definition
4.1.1. SMBus Host to Smart Battery or Fuel Cell System
4.1.2. Smart Battery Charger to Smart Battery or Fuel Cell System (or vice versa) 4.1.3. Smart Battery or Fuel Cell system to SMBus Host or Smart Battery Charger 4.2.
Smart Battery or Fuel Cell System Characteristics
4.2.1. Initial Conditions 4.2.2. Fuel Cell OFF State 4.2.3. Smart Fuel Soft OFF State 4.2.4. Smart Fuel Start Up Sate 4.2.5 Smart Fuel Power ON State
4.2.6.
Smart Fuel Hybrid State
4.2.7. Smart Fuel Idle State
4.2.8
State Diagram and System Transitions
4.2.9.
Safety Signal Hardware Requirements (Smart Battery Charger Interface)
5.
Smart Battery or Fuel Cell System Interface
5.1.
Standard SBDS for Fuel Cell Systems – SES Subset
5.1.1. BatteryMode() (0x03) 5.1.2. Temperature() (0x08) 5.1.3. Voltage() (0x09) 5.1.4. Current() (0x0a)
5.1.5. RelativeStateOfCharge() (0x0d) 5.1.6. RemainingCapacity() (0x0f) 5.1.7. FullChargeCapacity() (0x10) 5.1.8. AverageTimeToEmpty() (0x12) 5.1.9. BatteryStatus() (0x16)
5.1.10. ChargingCurrent() (0x14)
5 5 5 6 6 7 7 7 7 7 8 8 8 8
8 9 9
9 10 11 11 11 11 11 11 12 12 12 14 14 14
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
5.1.11. ChargingVoltage() (0x15) 5.1.12. CycleCount() (0x17) 5.1.13. DesignCapacity() (0x18) 5.1.14. DesignVoltage() (0x19) 5.1.15. ManufactureDate() (0x1b)
5.1.16. SerialNumber() (0x1c) 5.1.17. ManufacturerName() (0x20) 5.1.18. DeviceName() (0x21) 5.1.19. DeviceChemistry() (0x22) 5.1.20. ManufacturerData() (0x23) 5.2.
SBDS Addendum – Additional Functions for Fuel Cell Systems
5.2.1. DesignPower() (0x24) 5.2.2. StartTime() (0x25) 5.2.3. TotalRuntime() (0x26)
5.2.4. FCtemp() (0x27) 5.2.5. FCStatus(0x28)
5.2.6 FCMode() (0x29)
5.2.7. Auto_Soft_OFF (0x2a) 5.3.
SBDS for Fuel Cell Systems – In Addition to the SES Subset
5.3.1. ManufacturerAccess() (0x00) 5.3.2. RemainingCapacityAlarm() (0x01)
5.3.3. RemainingTimeAlarm() (0x02) 5.3.4. AtRate() (0x04)
5.3.5. AtRateTimeToFull() (0x05) 5.3.6. AtRateTimeToEmpty() (0x06) 5.3.7. AtRateOK() (0x07) 5.3.8. AverageCurrent() (0x0b) 5.3.9. MaxError() (0x0c)
5.3.10. AbsoluteStateOfCharge() (0x0e) 5.3.11. RunTimeToEmpty() (0x11) 5.3.12. AverageTimeToFull() (0x13)
5.3.13. SpecificationInfo() (0x1a)
Appendix A. Required functions for Fuel Cell Systems Appendix B. The command set in tabular form
15 15 16 16 16 16 17 17 17 18 19 19 19 19 20 20 21 22 22 22 22 22 22 23 23 23 24 24 24 25 25 25 27 28
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
1. Introduction
Smart Battery Data Specifications (SBDS) is an ideal solution for many of the issues related to batteries used in portable electronic equipment (such as laptop computer systems, cellular telephones or video cameras) but SBDS does not take into account Fuel Cell systems as power sources. This addendum is compatible with SBDS while adding new functions that allow greater control of Fuel Cell systems and will result in better performance. Additionally, this addendum specifically defines how Fuel Cell systems can respond to SBDS functions to remain compatible with current SBDS compatible devices.
Fuel Cell systems presently have a number of differences compared to traditional batteries. Fuel Cell systems can be turned on and off. They have a startup time during which they might not produce power or might produce only a very limited amount of power. Fuel Cell systems are refueled instead of recharged. Fuel Cell system peak power levels are generally far less than similarly sized battery packs. Fuel Cell systems degrade in a different manner than traditional batteries, becoming less efficient with age. Additionally some Fuel Cell systems may include internal rechargeable batteries.
The main differences of using Fuel Cell systems in place of batteries are: turning the Fuel Cell system “On” and the corresponding possible delay in power production, and maximum power limitations.
This addendum is not designed to limit innovation amongst battery manufacturers, but rather, provide the user and the SMBus Host with a consistent set of information about any particular Smart Battery or Fuel Cell System.
Additionally, although SMBUS and I2C interface are used as the underlying physical layer for this addendum, however these command sets can be implanted using other single or multi-wire interfaces.
1.1. Scope
This document specifies how Fuel Cell systems can return a data set that is compatible with SBDS. This document also defines new functions for Fuel Cell systems for added capabilities. This specification is generic with regard to the type of battery or Fuel Cell system chemistry, the battery or Fuel Cell system voltage, the battery pack or Fuel Cell system fuel cartridge capacity as well as the battery pack or system's physical packaging.
2. References
• • • • • • • • • • •
Smart Battery Data Specification, Revision 1.1, SBS-Implementers Forum, December, 1998 Smart Battery Charger Specification, Revision 1.1, SBS-Implementers Forum, December, 1998 Smart Battery Selector Specification, Revision 1.1, SBS-Implementers Forum, December, 1998
Smart Battery System Manager Specification, Revision 1.1, SBS-Implementers Forum, December, 1998 System Management Bus Specification, Revision 1.1, SBS-Implementers Forum, December, 1998 System Management Bus BIOS Interface Specification, Revision 1.0, February 15, 1995
ACPI Specifications, Version 1.0a, Intel Corporation, Microsoft Corporation, Toshiba Corp., July 1998 (http://www.teleport.com/~acpi)
The I²C-bus and how to use it, Philips Semiconductors document #98-8080-575-01.
ACCESS.bus Specifications -- Version 2.2, ACCESS.bus Industry Group, 370 Altair Way Suite 215, Sunnyvale, CA 94086 Tel (408) 991-3517
IEC SC21A - \"Alkaline Secondary Cells and Batteries\development of standard battery pack sizes and electrical specifications.)
IEC SC48B - \"Connectors\standards for batteries.)
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
3. Definitions
• • • • • • • • •
Fuel Cell: An electro-chemical device that converts fuel into electricity.
Fuel Cell System: A system consisting of a Fuel Cell, a fuel cartridge or storage tank, possibly a battery, and hardware that controls the Fuel Cell and provides present state, calculated and predicted information to its SMBus Host under software control. The content and method are described in this specification.
Fuel Cartridge: A container (either replaceable or refillable) that contains the fuel used by a Fuel Cell system to produce electricity.
Internal Battery: An optional rechargeable battery inside the Fuel Cell system which can be transparent to the host which can be recharged from external sources
I²C-bus: A two-wire bus developed by Phillips, used to transport data between low-speed devices.
Smart Battery: A battery equipped with specialized hardware that provides present state, calculated and predicted information to its SMBus Host under software control.
Smart Battery Charger: A battery charger that periodically communicates with a Smart Battery and alters its charging characteristics in response to information provided by the Smart Battery.
SMBus: The System Management Bus is a specific implementation of an I²C-bus that describes data protocols, device addresses and additional electrical requirements that is designed to physically transport commands and information between the Smart Battery, SMBus Host, Smart Battery Charger and other Smart Devices.
SMBus Host: A piece of portable electronic equipment powered by a Smart Battery. It is able to communicate with the Smart Battery and use information provided by the battery.
4. Fuel Cell System Overview
Controls Fuel Cell Optional Internal Battery Smart Battery Safety “T” Pin Smart Battery Charger AC-DC Converter (Unregulated)Cartridge System Host ACSmart Battery SMBus Status,CriticalEvents,ChargingData,Etc
The Fuel Cell System communicates with other devices (such as the SMBus Host and the Smart Battery Charger) via two separate communication interfaces:
- The first uses the SMBus CLOCK and DATA lines and is the primary communication channel between the Fuel Cell System and other SMBus devices. The Fuel Cell System will provide data when requested, send charging information to the Smart Battery Charger, and broadcast critical alarm information when parameters (measured or calculated) exceed predetermined limits within the particular Fuel Cell System.
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
- The other required communication interface is the secondary signaling mechanism or ‘Safety Signal’ (the ‘T-pin’ on a Smart Battery pack connector). This is a variable resistance output from the Smart Battery or Fuel Cell system which indicates when charging is permitted. If this ‘Safety Signal’ pin is left open, it will signal the Smart Battery Charger that charging is not allowed.
It is possible in some cases such as a tethered fuel system to include an internal rechargeable smart battery where this battery can be recharged by an external source. In these cases the system has to be able to communicate with this battery for its status as well as its charging status and requirements over the SMBus.
4.1. Smart Battery or Fuel Cell System Software Definition
4.1.1. SMBus Host to Smart Battery or Fuel Cell System
SMBus Host to Smart Battery or Fuel Cell System communications are performed:
• To allow the user to know the Smart Battery or Fuel Cell System’s remaining runtime
• To allow Smart Batteries or Fuel Cell System’s to provide accurate information to their user • To determine the SMBus Host's real-time power requirements
• To enable power management based on “real” values supplied by the battery or Fuel Cell system
• To enable battery or Fuel Cell system manufacturers to collect information about a Smart Battery or Fuel Cell
System’s usage
• To allow battery or Fuel Cell system manufacturers to electronically \"stamp\" batteries or Fuel Cell systems at
time of manufacture
• To allow the SMBus Host to change Fuel Cell system status (startup, shutdown, idle)
4.1.2. Smart Battery Charger to Smart Battery or Fuel Cell System (or vice versa)
Smart Battery Charger to Smart Battery or Fuel Cell System communications are performed:
• To allow Smart Batteries or Fuel Cell System internal batteries to be charged as rapidly and as safely as
possible
• To allow access to the \"correct\" charger algorithm for the battery or Fuel Cell system internal battery.
4.1.3. Smart Battery or Fuel Cell system to SMBus Host or Smart Battery Charger
Smart Battery or Fuel Cell System to SMBus Host or Smart Battery Charger communications are performed:
• To allow the Smart Battery or Fuel Cell System to warn other system components of potential problems.
• To allow the Smart Battery or Fuel Cell System to warn the user about potentially dangerous situations that they
can rectify.
• To allow the Smart Battery or Fuel Cell System internal battery to instruct the Smart Battery Charger what
Charge Current and Charge Voltage it would like to be charged with.
• To allow the Fuel Cell system to indicate its status (startup, shutdown, fuel cartridge removed).
4.2. Smart Battery or Fuel Cell System Characteristics
The Smart Battery or Fuel Cell System may or may not be present in a system. Additionally, it may dynamically be added or removed while the system is powered. Therefore, it must exhibit predictable behaviors when inserted in a
system and/or when the system is turned on. The following is a description of the battery or Fuel Cell system’s states and a description of the actions that take place as a result of changes.
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
4.2.1. Initial Conditions;
The system must detect when a Smart Battery or Fuel Cell System is present and this is done by using BatteryMode() status bit 10.as indicated by bit10 of BatteryMode() command.
Function (Data Value) Initial Value (Smart Battery) Initial Value (Fuel Cell Systems) Units RemainingCapacityAlarm() 10% of DesignCapacity() value 0 mAh RemainingTimeAlarm() 10 10 minutes Bit 15: Bit 15: BatteryMode() bit value
CAPACITY_MODE=0 Bit 14:
CHARGER_MODE=0 Bit 13:
ALARM_MODE=0 Bit 10 :
Fuel_Cell_Mode = 0 Bit 9:
PRIMARY_BATTERY=0 BIT 8:
CHARGE_CONTROLLER_ENABLED=0 Bit 7: INITIALIZED=1 CAPACITY_MODE=1 Bit 14:
CHARGER_MODE=1 Bit 13:
ALARM_MODE=1 Bit 10 :
Fuel_Cell_Mode = 1 Bit 9:
PRIMARY_BATTERY=0 BIT 8:
CHARGE_CONTROLLER_ENABLED=0 Bit 7: INITIALIZED=1 BatteryStatus() CycleCount() typically less than 5 typically less than 5 bit value decimal
4.2.2. Fuel Cell ‘OFF” State
The Fuel Cell System may enter the “Off State” whenever the SMBus Clock and Data lines both remain low for greater than 2.5 seconds or driven by the host to this state. In this condition the power is removed from the Fuel Cell and no communication will occur. If the Fuel Cell system has a physical “On/Off switch”, it will go into OFF state immediately when the switch is moved to the “Off” position and will stop communicating via SMBus.
Fuel Cell must enter this mode automatically in case of any critical alarms and or loss of system communications.
4.2.3. Soft-OFF State:
In this mode the Fuel Cell can communicate to the host or other system electronics. System may drive the Fuel Cell to this state from idle mode when the load no longer exists and or charging is complete.
The Fuel Cell must enter Soft OFF mode automatically after charging the optional internal battery is complete with or without the host intervention
The Fuel Cell enters this state whenever it detects that the SMBus Clock and Data lines go high and will remain in this mode until its operating mode is changed via the SFMode() function call.
The Fuel Cell may also automatically transition to Start Up state after entering Soft-Off state in order to prepare to produce power.
.The Fuel Cell system may not disrupt traffic on the SMBus, however the physical act of inserting a new device onto a live bus may cause an inadvertent communication interruption. The Smart Fuel Cell System may not begin broadcasting messages to either the SMBus Host or Smart Battery Charger for at least 10 seconds after entering the SMBus “On State.” Including the Soft-Off State.
4.2.4. STARTUP State:
In this state, the Fuel Cell system prepares itself to provide power since the fuel cell system can not deliver the load power immediately and requires a set up time (SetupTime(0x26h). The Fuel Cell should automatically enter this state initially by changing FCMode() upon power up and when ready it should transition to Idle state awaiting command to provide power.
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
4.2.5. Power ON State:
In this state, the Fuel Cell system is producing power to the load and could be charging the battery at the same time.
4.2.6. Hybrid State:
Hybrid state is when the load power requirements exceed the capability of the Fuel Cell. Under this condition the Fuel Cell is working in conjunction (parallel) with battery to produce the required platform power and must be able to toggle to the Power-ON state automatically once the load’s power is with in the Fuel Cell’s capability.
4.2.7. Idle State
In IDLE state the Fuel Cell System could deliver power and is ready to enter the Power On state. This state could also be used as a low power state (standby) where the Fuel Cell System is awaiting for the load to be turned on. The Fuel Cell system may also enter Idel state under alarm conditions
4.2.8 State Diagram and System Transitions
Power removed
Or Go-toLow Power StateStart Up/Turn-ONCommandOFF(000)SoftOFF(001)Start Up(010)Start UpCompleteLoad = OnPower Applied Or Go-to Communicating stateTurn-Off Now CMDTurn-Off Delayed (Hybrid Full)Or Error ConditionIDLE(011)Load ONCMDLoad OFFCMDPower Off-NowPower ON(100)Load > PmaxHybrid(101)Load < PmaxTransition Table
Host Fuel Cell Possible Conditions initiated initiated
OFF to Soft OFF 000 Æ 001 - - User initiated (On-Off Switch) Soft OFF to OFF 001 Æ 000 Alarm, System disconnect, Turn Of√ √ Soft OFF to Start Up 001 Æ 010 - System ON √ Start Up to Soft OFF 010 Æ 001 Error √ √ Start Up to Idle 010 Æ011 - √ Start-up complete, system interruptsIdle to Soft Off 011 Æ 001 Error, Alarm, Turn-OFF √ √ Idel to Power-ON/Hybrid 011 Æ 10x - Load ready, Toggle to battery if Pow√ Load Power to Idle 10x Æ 011 Load off command, Alarm, Error √ √
Note: All other Transitions are invalid and ignored.
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
4.2.9. Safety Signal Hardware Requirements (Smart Battery Charger Interface)
The Fuel Cell System, similar to Smart Batteries, must also provide an additional signal to allow for safe charging. This ‘Safety Signal’ is also commonly referenced as the ‘T-pin’ or ‘Thermistor’ on some Smart Battery hardware connectors. The ‘Safety Signal’ is an output from the Smart Battery and may be used by a Smart Battery Charger (or other device) to determine if charging of the Smart Battery is permitted. This signal is a variable resistance output as measured between the ‘Safety Signal’ pin and the negative terminal of the battery.
If a Fuel Cell System has an internal rechargeable battery that has the capability of being recharged by the Smart Battery Charger, it must have a Safety Signal Resistance of 2850Ω to 31.5kΩ. Otherwise, the Safety Signal should be open (Rss > 95k Ω). If a Fuel Cell system wants to stop the Smart Battery Charger from charging its internal battery, the Safety Signal should be open (Rss > 95k Ω).
The Smart Battery Charger’s capabilities are altered by the value of the Safety Signal. As a required safety feature, the charger must NOT charge a battery when it senses the resistance between the Safety Signal pin and ground to be in the range between 425 and 3150 ohms. The valid ranges of the Safety Signal are summarized below along with the charger’s capabilities for the range. (Please also refer to the Smart Battery Charger Specification.)
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
5. Smart Battery or Fuel Cell System Interface
The following functions are used by the Smart Battery or Fuel Cell System to communicate with a SMBus Host, Smart Battery Charger and other devices connected via the SMBus.
The SMBus Host, acting in the role of a SMBus master, uses the Read Word and Write Word protocols to communicate numeric data with the Smart Battery or Fuel Cell System. Non-numeric data, such as the ManufacturerName(), is read using the Read Block protocol.
The Host Device can obtain data that can then be either presented to a user or applied by the Device’s power
management system. Two types of data are available from the Smart Battery: static data and dynamic data. Static data includes items that are not changing, such as chemistry, the original capacity, or the design voltage. Dynamic data includes both measured and calculated information. Measured data is obtained by the monitoring electronics and includes items such as temperature, voltage and current. Calculated information is based on the battery or Fuel Cell system’s present state and the battery or Fuel Cell system’s characteristics, such as the remaining life at the present rate of drain.
The functions are described as follows:
FunctionName() 0xnn (command code)
Description: A brief description of the function.
Purpose: The purpose of the function, and an example where appropriate. SMBus Protocol: Refer to Section 6 for details.
Required: Is this function required for SES compatible Fuel Cell Systems? Data Type: Dynamic or Static
Input, Output or Input/Output: A description of the data supplied to or returned by the function. The data is described as follows:
Data type: The type of data the function conveys Units: The units the data is presented in Range: The range of valid data Granularity: described as percentage of a maximum value, determined by least accurate data. Accuracy: How \"good\" is the data.
Fuel Cell system: A description of how a Fuel Cell System will return information to this function to be compatible with SBDS and SES PX.
If an optional internal smart battery exists as part of the Fuel Cell, all commands associated with this battery return the same vales as any other smart battery in the system unless noted so.
A Fuel Cell System that complies with SBDS v1.1 must support all the command codes contained in this
specification. It must support the defaults as specified. Additionally, it must support all modes and functions specified except those which it can explicitly signal the presence or absence thereof (e.g. the presence of an internal charge controller and the ability to enable or disable that controller). Portions of this specification designated ‘optional’ are not required for compliance.
To be compatible with SBDS, Fuel Cell Systems must supply values for functions as described in the “Fuel Cell system” headings in sections 5.1.1-5.1.21 and 5.3.1-5.3.13. For extra functionality, Fuel Cell Systems must also supply values for functions as described in the “Fuel Cell system” headings in sections 5.2.1-5.2.6. To be compatible with SES function definitions, Fuel Cell Systems need only supply values for functions as described in the “Fuel Cell system” headings in sections 5.1.1-5.1.21.
5.1. Standard SBDS for Fuel Cell Systems – SES Subset
This section lists SES Px function definitions and the values that Fuel Cell Systems will report for these functions. SES Px functions are a subset of SBDS. For full compatibility with SBDS, Fuel Cell Systems must also return values for the
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
functions listed in section 5.3. In a sense, this is a guide to Fuel Cell system manufacturers as to how to make Fuel Cell Systems compatible with devices designed for standard Smart Batteries.
5.1.1. BatteryMode(03h)
Description: This function reports the battery system’s operational modes and capabilities, and flags minor conditions requiring attention.
Purpose: To allow the Host Device to determine the presence of Fuel Cell system and the particular data reporting formats. (See individual bit definitions). SMBus Protocol: Read or Write Word Required?: Yes
Data Type: Dynamic
Input/Output: unsigned int – bit mapped Units: not applicable Range: 0…1
Fuel Cell system: In SBDS, BatteryMode has eight reserved bits along with eight defined bits (see SBDS spec). The currently reserved bits are 2-6 and 10-12. Fuel Cell systems will use Bit,10, to report presence of Fuel Cells as an alternative source of energy The BatteryMode flag bit 10 is set when the SBDS Primary Exchange electronics are representing a fuel-cell device. This is an indication to the Host Device that there may be load limitations, start-up delays, or other aspects of Fuel Cell operation that may change operational parameters. Additionally, the Host device will recognize the new additional functions such as DesignMaxCurrent(0x25),StartTime(0x26), FuelCellRegister(0x2A) and other optional new functions defined in the SBDS addendum for Fuel Cells.
Bit 15 (read only) always is set (1) as Capacity_mode () for current is not supported for Fuel Cells (It only reports capacity in Watts)
5.1.2. Temperature(08h)
Description: Returns the battery pack’s internal temperature in degrees Kelvin (ºK)
Purpose: The Temperature function provides an accurate temperature for use by the battery-powered device’s thermal management system. Since Fuel Cell systems may have a variety of internal temperatures, it is more appropriate that they report ambient temperature or internal battery temperature. SMBus Protocol: Read Word Required?: Yes
Data Type: Dynamic
Output: unsigned int – battery temperature in tenth degree Kelvin increments Units: 0.1 ºK Range: 0 to +6553.5 ºK Granularity: 1.0 ºK or better Accuracy: ± 4 ºK
Fuel Cell system: This function is used only for reporting internal battery temperature. For reporting internal temperatures associated with Fuel Cell, FCTemp() command must be used.
5.1.3. Voltage(09h)
Description: Returns the battery pack or Fuel Cell system voltage in milli-Volts (mV). Purpose: The Voltage function provides the battery or Fuel Cell system terminal voltage SMBus Protocol: Read Word Required?: Yes
Data Type: Dynamic
Output: unsigned int – battery or Fuel Cell system terminal voltage in milli-Volts Units: mV Range: 0 to 65,535 mV Granularity: 0.5% of DesignVoltage Accuracy: ± 2.0% of DesignVoltage Fuel Cell system: returns same.
5.1.4. Current(0Ah)
Description: Returns the current being supplied through the battery or Fuel Cell system’s terminals in milli-Amps (mA) Purpose: The Current function provides a measurement of the current flowing out of the battery or Fuel Cell system. SMBus Protocol: Read Word
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
Required?: Yes
Data Type: Dynamic
Output: unsigned int – discharge rate in mA increments, negative for discharge Units: mA Range: 0 to -32,768 mA for discharge Granularity: 0.5% of DesignCapacity Accuracy: ± 2.0% of DesignCapacity Fuel Cell system: returns same.
5.1.5. RelativeStateOfCharge(0Dh)
Description: Returns the predicted remaining battery capacity or Fuel Cell system fuel cartridge capacity expressed as a percentage of the DesignCapacity (%)
Purpose: The RelativeStateOfCharge function is used to estimate the amount of charge remaining in the battery or fuel in the Fuel Cell system fuel cartridge(s). SMBus Protocol: Read Word Required?: Yes
Data Type: Dynamic
Output: unsigned int – percent of remaining capacity Units: % Range: 0 to 100% Granularity: 2% Accuracy: 10%
Fuel Cell system: Returns the predicted remaining fuel in fuel cartridge expressed as a percentage of the DesignCapacity (%). If no fuel cartridge is installed, return 0.
5.1.6. RemainingCapacity(0Fh)
Description: Returns the predicted remaining battery capacity or Fuel Cell system internal battery capacity in milli-Amp-hours (mAh)
Purpose: The RemainingCapacity function returns the battery or Fuel Cell system fuel cartridge(s) remaining capacity in absolute terms but relative to a specific discharge rate. SMBus Protocol: Read Word Required?: No
Data Type: Dynamic
Output: unsigned int – remaining charge in mAh Units: mAh Range: 0 to 65,535 mAh Granularity: 0.5% of DesignCapacity Accuracy: not applicable
Fuel Cell system: If the Fuel Cell system has an internal rechargeable battery, this function returns the predicted remaining capacity in that battery in milli-Amp-hours (mAh). If the Fuel Cell system does not have an internal rechargeable battery, return the result of this calculation: RelativeStateOfCharge(0Dh)* DesignCapacity(18h)
5.1.7. FullChargeCapacity(10h)
Description: Returns the predicted pack capacity or Fuel Cell system internal battery capacity when it is fully charged in milli-Amp-hours (mAh)
Purpose: The FullChargeCapacity function provide the user with a means of understanding the “tank size” of their battery or Fuel Cell system fuel cartridge(s). SMBus Protocol: Read Word Required?: No
Data Type: Dynamic
Output: unsigned int – estimated full charge capacity in mAh Units: mAh Range: 0 to 65,535 mAh Granularity: 0.5% of DesignCapacity Accuracy: not applicable
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
Fuel Cell system: If the Fuel Cell system has an internal rechargeable battery, this function returns the predicted pack capacity of that battery when it is fully charged in milli-Amp-hours (mAh). If the Fuel Cell system does not have an internal rechargeable battery, return the same value as DesignCapacity(18h)
5.1.8. AverageTimeToEmpty(12h)
Description: Returns a rolling average of the predicted remaining battery life or Fuel Cell system fuel cartridge remaining runtime in minutes.
Purpose: The AverageTimeToEmpty displays state-of-charge information in a more useful way. By averaging the estimations, the remaining time will not appear to “jump” around. SMBus Protocol: Read Word Required?: Yes
Data Type: Dynamic
Output: unsigned int – minutes of operation left Units: minutes Range: 0 to 65,535 min Granularity: 5 minutes Accuracy: 25 minutes Invalid Data Indication: 65,535 indicates battery or Fuel Cell system is not being discharged.
Fuel Cell system: Returns a rolling average of the predicted remaining number of minutes of runtime of the Fuel Cell system using the currently installed fuel cartridge(s). If the Fuel Cell system is in PRODUCING POWER MODE, this number is calculated based on power out of the Fuel Cell system. If the Fuel Cell system is not in PRODUCING
POWER MODE, return 65,535. If no fuel cartridge is installed, return time until Fuel Cell system enters SHUTDOWN MODE or IDLE MODE from PRODUCING POWER MODE.
5.1.9. BatteryStatus(16h)
Description: Returns the status word which contains alarm and status bit flags which indicate end-of-discharge, over-temperature, and other conditions.
Purpose: The BatteryStatus() function is used by the Host Device to get alarm and status bits, as well as error codes from the Smart Battery.
SMBus Protocol: Read Word Required?: Yes
Data Type: Dynamic
Output: unsigned int – Status Register with alarm conditions bit mapped as follows: *****Alarm Bits*****
0x8000 OVER_CHARGED_ALARM
0x4000 TERMINATE_CHARGE_ALARM 0x2000 reserved
0x1000 OVER_TEMP_ALARM
0x0800 TERMINATE_DISCHARGE_ALARM 0x0400 reserved
0x0200 REMAINING_CAPACITY_ALARM 0x0100 REMAINING_TIME_ALARM *****Status Bits***** 0x0080 INITIALIZED 0x0040 DISCHARGING 0x0020 FULLY_CHARGED 0x0010 FULLY_DISCHARGED
Fuel Cell system: Returns only internal battery alarms if present. A new command FCStatus has been defined for Fuel Cell Alarm conditions.
5.1.10. ChargingCurrent(14h)
Description: Returns the Smart Battery’s desired charging rate in milli-Amps (mA)
Purpose: The ChargingCurrent function returns the maximum current that a Smart Battery Charger may deliver to the Smart Battery. In combination with the ChargingVoltage these functions permit a Smart Battery Charger to dynamically adjust its charging profile (current/voltage) for optimal charge. The battery can effectively turn off the Smart Battery
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
Charger by returning a value of 0 for this function. Smart Battery Chargers may be operated as a constant voltage source above their maximum regulated current range by returning a ChargingCurrent value of 65535. Note: The Smart Battery Charger is expected to respond in one of three ways:
• Supply the current requested
• Supply its maximum current if the request is greater than its maximum and less than 65535 • Supply its maximum safe current if the request is 65535
Note: It is incumbent upon the battery or Fuel Cell system to be able to withstand considerable variations in the actual charging current supplied if the load varies rapidly during charging. SMBus Protocol: Read Word Required?: No
Data Type: Dynamic
Output: unsigned int – maximum charger output current in mA Units: mA Range: 0 to 65,535 mA Granularity: 0.5% of DesignCapacity Accuracy: not applicable Invalid Data Indication: 65,535 indicates the Smart Battery Charger should operate as a voltage source
outside its maximum regulated current range.
Fuel Cell system: If the Fuel Cell System has an internal rechargeable battery, this function returns that battery’s desired charging rate in milli-Amps (mA). If the Fuel Cell system does not have an internal rechargeable battery, this function returns 0.
5.1.11. ChargingVoltage(15h)
Description: Returns the Smart Battery’s desired charging voltage in milli-Volts (mV). This represents the maximum voltage which may be provided by the Smart Battery Charger during charging.
Purpose: The ChargingVoltage function sets the maximum voltage that a Smart Battery Charger may deliver to the Smart Battery. In combination with the ChargingCurrent function these values permit a Smart Battery Charger to dynamically adjust its charging profile (current/voltage) for optimal charge. The battery can effectively turn off the Smart Battery Charger by returning a value of 0 for this function. Smart Battery Chargers may be operated as a constant current source above their maximum regulated voltage range by returning a ChargingVoltage value of 65535. Note: The Smart Battery Charger is expected to respond in one of three ways:
• Supply the voltage requested
• Supply its maximum voltage if the request is greater than its maximum and less than 65535 • Supply its maximum voltage if the request is 65535
SMBus Protocol: Read Word Required?: No Data Type: Static
Output: unsigned int –charger output voltage in mV Units: mV Range: 0 to 65,535 mV Granularity: 0.5% of the DesignVoltage Accuracy: not applicable Invalid Data Indication: 65,535 indicates the Smart Battery Charger should operate as a current source outside
its maximum regulated voltage range.
Fuel Cell system: If the Fuel Cell System has an internal rechargeable battery, this function returns that battery’s desired charging voltage in milli-Volts (mV). If the Fuel Cell system does not have an internal rechargeable battery, this function returns 0.
5.1.12. CycleCount(17h)
Description: Returns the number of cycles the battery or Fuel Cell system has experienced. A cycle is defined as: An amount of discharge approximately equal to the value of DesignCapacity.
Purpose: The CycleCount function provides a means to determine the battery’s wear. It may be used to give advanced warning that the battery is nearing its end of life. The CycleCount returned value multiplied by the DesignCapacity value can give an approximate “odometer” reading for the total capacity delivered by the battery. SMBus Protocol: Read Word
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
Required?: No
Data Type: Dynamic
Output: unsigned int –count of charge/discharge cycles the battery or Fuel Cell system’s internal battery has
experienced.
Units: cycle Range: 0 to 65,534 cycles; 65,535 indicates battery has experienced 65,535 or more cycles. Granularity: 1 cycle Accuracy: absolute count
Fuel Cell system: This function returns the number of start/stop cycles that Fuel Cell has accumulated over its life.
5.1.13, DesignCapacity(18h)
Description: Returns the full capacity of a new battery pack or Fuel Cell system fuel cartridge(s) in milli-Amp-hours (mAh). This value is expressed in mAh at a C/5 discharge rate.
Purpose: The DesignCapacity function provides a static value representing the full charge capacity of the battery pack or Fuel Cell system fuel cartridge(s). It can be used along with the RelativeStateOfCharge value to determine a remaining capacity value in mAh. SMBus Protocol: Read Word Required?: Yes
Data Type: Dynamic
Output: unsigned int – the battery or Fuel Cell system fuel cartridge capacity in mAh Units: mAh Range: 0 to 65,535 mAh
Fuel Cell system: Returns the full capacity in milli-Amp-hours (mAh) of the fuel cartridge(s) being used by the Fuel Cell system. This value is expressed in mAh and is calculated using the Fuel Cell system’s rated efficiency at a rolling average of its current power usage. If no fuel cartridges are installed, return 0. 5.1.14. DesignVoltage(19h)
Description: Returns the design voltage of a new battery pack or Fuel Cell system in milli-Volts (mV).
Purpose: The DesignVoltage function can be used to give additional information about a particular battery or Fuel Cell system’s terminal voltage. SMBus Protocol: Read Word Required?: Yes Data Type: Static
Output: unsigned int –the battery or Fuel Cell system’s designed terminal voltage in mV Units: mV Range: 0 to 65,535 mV Fuel Cell system: returns same.
5.1.15. ManufactureDate(1Bh)
Description: This function returns the date the cell pack was manufactured in a packed integer. The date is packed in the following fashion: (Year-1980)*512+Month*32+day.
Purpose: The ManufactureDate provides the system with information that can be used to uniquely identify a particular battery or Fuel Cell system. It also helps indicate the age of the battery. SMBus Protocol: Read Word Required?: Yes Data Type: Static
Output: unsigned int – packed date of manufacture
Fuel Cell system: returns same. 5.1.16. SerialNumber(1Ch)
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
Description: This function is used to return a serial number. This number when combined with the ManufacturerName, the DeviceName, and the ManufacturerDate will uniquely identify the battery.
Purpose: The SerialNumber function is used to help identify a particular battery or Fuel Cell system. SMBus Protocol: Read Word Required?: Yes Data Type: Static Output: unsigned int Range: 0 to 65,535 Fuel Cell system: returns same.
5.1.17. ManufacturerName(20h)
Desciption: This function returns a character array containing the battery or Fuel Cell manufacturer’s name. For example, “BestBatt” would identify the battery or Fuel Cell’s manufacturer as BestBatt.
Purpose: The ManufactureName function returns the name of the battery or Fuel Cell system manufacturer or assembler and is used for identification. SMBus Protocol: Read Block Required?: Yes Data Type: Static
Output: string – character string – LIMITED TO EIGHT (8) CHARACTERS Fuel Cell system: returns same. 5.1.18. DeviceName(21h)
Description: This function returns a character string that contains the battery or Fuel Cell’s name. For example, a DeviceName of “SamrtB” would indicate that the battery is a model SmartB.
Purpose: The DeviceName function returns the battery or Fuel Cell system’s name and is used to uniquely identify the battery or Fuel Cell system. SMBus Protocol: Read Block Required?: Yes Data Type: Static
Output: string – character string – LIMITED TO EIGHT (8) CHARACTERS Fuel Cell system: returns same.
5.1.19. DeviceChemistry(22h)
Description: This function returns a character string that contains the battery or Fuel Cell’s chemistry. For example, if the DeviceChemistry function returns “LS02,” the battery pack would contain primary lithium cells. Purpose: The DeviceChemistry function gives cell chemistry information. SMBus Protocol: Read Block Required?: Yes Data Type: Static
Output: string – character string – LIMITED TO FOUR (4) CHARACTERS
Note: The following is a partial list of chemistries and their expected abbreviations. These abbreviations are NOT case sensitive.
Lithium Sulfur Dioxide LSO2 Lithium Manganese Dioxide LMnO
Lithium LCFx Lead Acid PbAc Lithium Ion LION Nickel Cadmium NiCd Nickel Metal Hydride NiMH Nickel Zinc NiZn Rechargeabe Alkaline-Manganese RAM Zinc Air ZnAr Lithium Polymer LiP
Additional chemistry types:
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
Hydrogen Fuel Cell NaBH Fuel Cell
Reformed Methanol Fuel Cell Direct Methanol Fuel Cell Formic Acid Fuel Cell Butane Fuel Cell Propane Fuel Cell Solid Oxide Fuel Cell
H2FC BHFC RMFC DMFC FAFC BSFC PSFC SOFC
5.1.20. ManufacturerData(23h) – OPTIONAL
Description: This function is optional and its meaning is implementation specific. It may be used by a battery
manufacturer or silicon supplier to return specific version information, internal calibration information, or some other manufacturer specific function. There is no implied or required use for this function and therefore it may be used for multiple purposes. Fuel Cell systems may use this to return additional system information including internal temperatures, component status, and additional error codes.
Purpose: This function’s purpose is manufacturer specific. No functional requirement is implied although example uses are mentioned in this text.
SMBus Protocol: Read Block (Write Block Optional) Required?: No
Data Type: Dynamic
Output: Block – Content determined by the Smart Battery’s manufacturer Fuel Cell system: returns same.
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
5.2. SBDS Addendum – Additional Functions for Fuel Cell Systems
For compatibility with Fuel Cell systems, several new required functions need to be added to the standard set of SBDS defined functions
5.2.1. DesignMaxPower(24h)
Description: Returns the maximum continuous net current of a Fuel Cell system in milli-Watts (mW).
Purpose: The DesignMaxCurrent function provides the maximum continuous power that a Fuel Cell system can provide. SMBus Protocol: Read Word Required?: Yes
Data Type: Dynamic
Output: unsigned int – design maximum current in milli watt increments Units: 10 milli Watts Range: 0 to 65,535
5.2.2. StartTime(25h)
Description: Returns the time until the Fuel Cell System is capable of providing its DesignMaxPower in seconds (s) Purpose: The StartTime is useful when hybridizing with a second power source to determine the most efficient usage of the Fuel Cell system. If the Fuel Cell system is in Power ON mode StartTime returns 0. If the Fuel Cell system is in STARTUP MODE or IDLE MODE, StartTime returns a value calculated from real internal and environmental
conditions. If the Fuel Cell system is in SHUTDOWN MODE StartTime returns either a standard startup time for the Fuel Cell system, or a value calculated from real time internal and environmental conditions. If the Fuel Cell System can provide instant power out, return 0. If the Fuel Cell System does not know when it will be able to provide power, return 65,535
SMBus Protocol: Read Word Required?: Yes
Data Type: Dynamic
Output: unsigned int – start time in s Units: s Range: 0 to 65,534 s. 65,535 means system can’t predict time.
5.2.3. TotalRuntime(26h)
Description: Returns the total runtime that the battery or Fuel Cell system has accumulated over its life.
Purpose: The TotalRuntime function provides a means to determine the Fuel Cell system’s wear. It may be used to give advanced warning that the Fuel Cell system is nearing its end of life. Although serving a similar purpose as CycleCount, TotalRuntime is a better indicator of system wear for some Fuel Cell systems. If the battery or Fuel Cell system can’t calculate its total runtime, it may return a value of: CycleCount*DesignCapacity for this function. SMBus Protocol: Read Word Required?: No
Data Type: Dynamic
Output: unsigned int – count of runtime in hours that the battery or Fuel Cell system has experienced. Units: hours Range: 0 to 65,534 hours; 65,535 indicates system has experienced 65,535 or more hours of total runtime. Granularity: 1 hour Accuracy: 5 hours
5.2.4. FCTemp(27h)
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
Description: Returns the internal temperature of Fuel Cell stack and or any reformers associated with the Fuel Cell in a two byte format. The upper byte (MSB) reports the Fuel Cell’s STACK temperature while the lower byte (LSB) reports the Reformer’s temperature SMBus Protocol: Read Word Required?: Yes
Data Type: Dynamic Output: unsigned int
Units: Temperature in degrees Celsius.
Granularity: 1 or 2 degrees Celsius based on FCMode() bit 12 setting Range: 0 – 255 / 511 Degrees Celsius
5.2.5. FCStatus(28h)
Description: This function communicates various Fuel Cell status, presence of fuel cartridge and internal battery . Purpose: to allow communication between Fuel Cell and system electronics SMBUS protocol, Read Required: Yes
DataType: Dynamic Input / Output: Unsigned integer bit mapped Units: N/A
15 MSB 8 7 LSB 0 R R res res R R R R res res res res res R R R
The following table summarizes the meanings of the individual bits of the FCStatus() word and specifies the default values if any..
Internal_battery 15 Read 0= absence of optional internal battery
1= presence of optional internal battery
Cartridge_Status 14 Read =0 absence of fuel cartridge
1= presence of fuel cartridge
Reserved 13-12 - Alarms conditions 8-11 Read 1111 = INITIALIZED
1000 = OVERLOAD
0111 = CELL DAMAGE (MEA) 0110 =OVER_TEMP_ALARM
0101 = REMAINING FUEL_CAPACITY_ALARM 0100 = REMAINING_FUEL_TIME_ALARM 0011 =INSUFFICIENT_AIR_FLOW 0010 = LIQUID LEAKAGE
0001 = BOP DAMAGE (PUMP/COMPRESSOR/ETC) 0000 = NO ALARMS
All other values reserved for future use
Reserved 3-7 - State 2-0 Read 000 Fuel Cell is in OFF state
001 Fuel Cell is in soft-OFF state (responds to commands) 010 = Fuel Cell is in Startup mode
011 = Fuel Cell is in Idle mode (load off)
100 = Fuel Cell is ON and producing power or charging
101 = Fuel Cell is ON and producing power in parallel with battery (running in Hybrid mode) Other values: Reserved
Specific Definitions of each bit:
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
Internal_Battery: Setting this bit indicates the existence of an internal battery used only by Fuel Cell system for startup. Cartridge_Status: This bit indicates the presence or absence of fuel cartridge
Alarm condtions_: These bits indicate alarm conditions which require host or controller service. For example if
INSUFFICIENT AIR FLOW alarm is set whenever the Fuel Cell system detects that it is not able to breathe enough air to produce full power. When this condition is set, load should be reduced or shutoff.
This alarm bits must be cleared when the Fuel Cell system detects that the condition no longer exists.
State: refer to Fuel Cell systems modes for description of these modes
5.2.6 FCMode (29h)
Description: This function configures various Fuel Cell states and or settings. Purpose: to allow changing Fuel Cell mode of operation by the Fuel Cell or Host SMBUS protocol, Read or Write Word Required: Yes
DataType: Dynamic Input / Output: Unsigned integer bit mapped Units: N/A.
15 MSB 8 7 LSB 0 res res RW RW res res res res res res res res R/W R/W R/W RW
The following table summarizes the meanings of the individual bits of the FCMode() word and specifies the default values if any
Reserved 14-15 - Fuel Cell Selector 13 R/W 0= information from or to internal battery 1=Information from or to Fuel Cell
FCTemp_granularity 12 R/W 0 = 1 degrees C ( FCTemperature() )
1 = 2 degrees C ( FCTemperature())
Reserved 11-4 - Change Status Enable 3 R/W 0 = FCMode() change disabled
1 = FC(mode() change enabled
Set-Mode 0-2 R/W 000 Set Fuel Cell to off State
001 Set Fuel Cell to soft-off sate (responds to commands)
010 = Set Fuel Cell to startup mode
011 = Set Fuel Cell to idle mode (load off)
100 = Set Fuel Cell to ON and producing power or charging
101 = Set Fuel Cell to ON and producing power in parallel with battery (running in Hybrid mode) Other values: Reserved
Specific Definitions for each bit:
Fuel Cell Selector: This bit selects the targeted component by the host for communication which could be either the Fuel Cell or its internal battery
FCTemp_granularity: This bit sets the maximum possible temperature ranges. See FCTemp()
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
Change Status Enable: Setting this bit allows changes via FCMode() command.
Set-Mode: Same as State mode in FCStatus() command, except that by using FCMode() command one can change the operating state of the Fuel Cell.
5.2.7 Auto_Soft-OFF(2Ah)
Description: This command transitions the Fuel Cell to the Soft OFF
Purpose: Auto-Soft-OFF is useful when system has detected charge completion and or load removal, however is awaiting possible changes in system usage whereby it allows adoption of power management policies. SMBus Protocol: Read Word Required?: Optional Data Type: Dynamic
Output: unsigned int – awaiting Soft-Off command Units: s Range: 0 to 65,535 s.
5.3. SBDS for Fuel Cell Systems – In Addition to the SES Subset
This section lists standard SBDS function definitions not already described This section, along with section 5.1 is a guide to Fuel Cell system manufacturers as to how to make Fuel Cell Systems compatible with devices designed for standard Smart Batteries.
5.3.1. ManufacturerAccess() (0x00)
Description: This function is optional and its meaning is implementation specific. Purpose: The ManufacturerAccess() function's purpose is manufacturer specific. SMBus Protocol: Read or Write Word Data Type: Static
Input/Output: word -- Content determined by the Smart Battery's manufacturer Fuel Cell system: Returns same.
5.3.2. RemainingCapacityAlarm() (0x01)
Description: Sets or gets the Low Capacity alarm threshold value. Whenever the RemainingCapacity() falls below the Low Capacity value, the Smart Battery or Fuel Cell System sends AlarmWarning() messages to the SMBus Host with the REMAINING_CAPACITY_ALARM bit set. A Low Capacity value of 0 disables this alarm.
Purpose: The RemainingCapacityAlarm() function can be used by systems to indicate a first level near end of discharge state.
SMBus Protocol: Read or Write Word Data Type: Dynamic
Input/Output: unsigned int -- value below which Low Capacity messages will be sent Units: mAh @ C/5 or DesignMaxCurrent() value Range: 0 to 65,534 mAh Accuracy: see RemainingCapacity()
Fuel Cell system: If the Fuel Cell System has an internal rechargeable battery and is in STARTUP MODE or IDLE MODE, return the value needed for the internal battery to startup or finish starting up the system. If no fuel cartridges are installed, or if the Fuel Cell System is in PRODUCING POWER MODE or SHUTDOWN MODE, return 0.
5.3.3. RemainingTimeAlarm() (0x02)
Description: Sets or gets the Remaining Time alarm value. Whenever the AverageTimeToEmpty() falls below the Remaining Time value, the Smart Battery sends AlarmWarning() messages to the SMBus Host with the REMAINING_TIME_ALARM bit set. A Remaining Time value of 0 effectively disables this alarm.
Purpose: The RemainingTimeAlarm() function can be used by systems that want to adjust when the remaining time alarm warning is sent.
SMBus Protocol: Read or Write Word Data Type: Dynamic
Input/Output: unsigned int -- the point below which Remaining Time messages will be sent
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
Units: minutes Range: 0 to 65,535 minutes Accuracy: see AverageTimeToEmpty()
Fuel Cell system: Returns same. Default is 10 minutes.
5.3.4. AtRate(04h)
Description: The AtRate() function is the first half of a two-function call-set used to set the AtRate value used in calculations made by the AtRateTimeToFull(), AtRateTimeToEmpty(), and AtRateOK() functions. Purpose:
• When the AtRate value is positive, the AtRateTimeToFull() function returns the predicted time to fullcharge at
the AtRate value of charge.
• When the AtRate value is negative, the AtRateTimeToEmpty() function returns the predicted operating time at
the AtRate value of discharge.
• When the AtRate value is negative, the AtRateOK() function returns a Boolean value that predicts the battery or
Fuel Cell system's ability to supply the AtRate value of additional discharge energy for a minimum of 10 seconds.
SMBus Protocol: Read or Write Word Data Type: Dynamic
Input/Output: unsigned int -- the point below which Remaining Time messages will be sent
Units: mA
Charge Range: 1 to 32,767 mA Discharge Range: -1 to -32,768 mA Granularity: 1 unit
Fuel Cell system: See AtRateTimeToFull(), AtRateTimeToEmpty(), and AtRateOK() functions
5.3.5. AtRateTimeToFull(05h)
Description: Returns the predicted remaining time to fully charge the battery or Fuel Cell system internal battery at the previously written AtRate value in mA.
Purpose: The AtRateTimeToFull() function is part of a two-function call-set used to determine the predicted remaining charge time at the AtRate value (mA). Refer to AtRate() for additional usage information. SMBus Protocol: Read Word Data Type: Dynamic
Output: unsigned int -- predicted time in minutes to fully charge the battery
Units: minutes Range: 0 to 65,534 min Granularity: 2 min or better Accuracy: ±MaxError()∗FullChargeCapacity() ÷ AtRate()
Invalid Data Indication: 65,535 indicates the battery is not being charged
Fuel Cell system: Returns same for Fuel Cell system internal battery. If the Fuel Cell System does not have an internal rechargeable battery, this function returns 65,535.
5.3.6. AtRateTimeToEmpty(06h)
Description: Returns the predicted remaining operating time if the battery or Fuel Cell system fuel cartridge is discharged at the previously written AtRate value.
Purpose: The AtRateTimeToEmpty() function is part of a two-function call-set used to determine the remaining operating time at the AtRate value. Refer to AtRate() for additional usage information. SMBus Protocol: Read Word Data Type: Dynamic
Output: unsigned int -- estimated operating time left
Units: minutes Range: 0 to 65,534 min Granularity: 2 min or better
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
Accuracy: −0,+MaxError()∗DesignCapacity() ÷ AtRate()
Invalid Data Indication: 65,535 indicates the battery or Fuel Cell system is not being discharged
Fuel Cell system: Returns the predicted remaining time until the attached fuel cartridge(s) are empty if the Fuel Cell system fuel cartridge is discharged at the previously written AtRate value.
5.3.7. AtRateOK(07h)
Description: Returns a Boolean value that indicates whether or not the battery or Fuel Cell system can deliver the
previously written AtRate value of additional energy for 10 seconds (Boolean). If the AtRate value is zero or positive, the AtRateOK() function will ALWAYS return true.
Purpose: The AtRateOK() function is part of a two-function call-set used by power management systems to determine if the battery or Fuel Cell system can safely supply enough energy for an additional load. Refer to AtRate() for additional usage information. SMBus Protocol: Read Word Data Type: Dynamic
Output: Boolean -- indicates if the battery can supply the additional energy requested
Units: Boolean Range: TRUE (non-zero), FALSE (zero) Granularity: not applicable Accuracy: not applicable
Fuel Cell system: Returns same. If the AtRate value is positive, return TRUE. If the AtRate value is negative, and if − AtRate() value − Current() < DesignMaxCurrent(), then return TRUE, otherwise return FALSE.
5.3.8. AverageCurrent(0Bh)
Description: Returns a one-minute rolling average based on the current being supplied (or accepted) through the battery or Fuel Cell system's terminals (mA).
Purpose: The AverageCurrent() function provides the average current flowing into or out of the battery or Fuel Cell system for the power management system. SMBus Protocol: Read Word Data Type: Dynamic
Output: signed int -- charge/discharge rate in mA increments - positive for charge, negative for discharge
Units: mA Range: 0 to 32,767 mA for charge or 0 to -32,768 mA for discharge Granularity: 0.2% of the DesignCapacity() or better Accuracy: ±1.0% of the DesignCapacity()
Fuel Cell system: Returns same.
5.3.9. MaxError(0Ch)
Description: Returns the expected margin of error (%) in the state of charge calculation. For example, when MaxError() returns 10% and RelativeStateOfCharge() returns 50%, the Relative StateOfCharge() is actually between 50 and 60%. Purpose: The MaxError() function does not exist on most systems today. SMBus Protocol: Read Word Data Type: Static
Output: unsigned int -- percent uncertainty for selected information
Units: % Range: 0 to 100% Granularity: 1% Accuracy: not applicable
Fuel Cell system: Returns uncertainty of fuel cartridge fill estimate. Default value for new cartridge is 5%. As cartridge empties, typical value may increase to 10% or more. If no fuel cartridge is installed, return 10%
5.3.10. AbsoluteStateOfCharge(0Eh)
Description: Returns the predicted remaining battery or Fuel Cell system fuel cartridge capacity expressed as a percentage of DesignCapacity() (%).
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
Purpose: See RelativeStateOfCharge() function description. SMBus Protocol: Read Word Data Type: Dynamic
Output: unsigned int -- percent of remaining capacity
Units: % Range: 0 to 100+% Granularity: 1% Accuracy: -0, +MaxError()
Fuel Cell system: Returns the predicted remaining fuel cartridge capacity expressed as a percentage of DesignCapacity() (%). If no fuel cartridge is installed, return 0.
5.3.11. RunTimeToEmpty(11h)
Description: Returns the predicted remaining battery life or Fuel Cell system fuel cartridge runtime at the present rate of discharge (minutes).
Purpose: The RunTimeToEmpty() can be used by the power management system to get information about the relative gain or loss in remaining life in response to a change in power policy. This information is NOT the same as the AverageTimeToEmpty(), which is not suitable to determine the effects that result from a change in power policy. SMBus Protocol: Read Word Data Type: Dynamic
Output: unsigned int -- minutes of operation left
Units: minutes Range: 0 to 65,534 min Granularity: 2 min or better Accuracy: -0, +MaxError() * DesignCapacity() / Current()
Invalid Data Indication: 65,535 indicates battery is not being discharged
Fuel Cell system: Returns the predicted remaining fuel cartridge runtime in minutes at the present rate of discharge. If no fuel cartridge is installed, return 0.
5.3.12. AverageTimeToFull(13h)
Description: Returns a one minute rolling average of the predicted remaining time until the Smart Battery or Fuel Cell System’s internal battery reaches full charge (minutes).
Purpose: The AverageTimeToFull() function can be used by the SMBus Host's power management system to aid in its policy. It may also be used to find out how long the system must be left on to achieve full charge. SMBus Protocol: Read Word Data Type: Dynamic
Output: unsigned int -- remaining time in minutes
Units: minutes Range: 0 to 65,534 min Granularity: 2 min or better Accuracy: ±MaxError() * FullChargeCapacity() / AverageCurrent() Invalid Data Indication: 65,535 indicates the battery is not being charged
Fuel Cell system: If the Fuel Cell system has an internal rechargeable battery, this function returns a one minute rolling average of the predicted remaining time until it reaches full charge (minutes). If the Fuel Cell system does not have an internal rechargeable battery, return 65,534.
5.3.13. SpecificationInfo(1Ah)
Description: Returns the version number of the Smart Battery specification the battery pack or Fuel Cell system
supports, as well as voltage and current and capacity scaling information in a packed unsigned integer. Power scaling is the product of the voltage scaling times the current scaling.
This value may also indicate a version of SMBus error checking implementation. Refer to the SMBus Specification for actual implementation information.
The SpecificationInfo is packed in the following fashion: (major version number * 0x10 + minor revision number) + (voltage scaling + current scaling * 0x10) * 0x100.
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
Purpose: The SpecificationInfo() function is used by the SMBus Host's power management system to determine what information the Smart Battery can provide. It can be used by Smart Battery Systems where the defined 16-bit data values do not provide enough range for higher power applications. SMBus Protocol: Read Word Data Type: Static
Output: unsigned int -- packed specification number and scaling information
Field Bits Used Format Allowable Values Revision 0...3 4 bit binary value 0001 - Version 1.0 and 1.1
all other values reserved
Version 4...7 4 bit binary value 0001 – Version 1.0 0010 – Version 1.1
VScale
8...11
0011 - Version 1.1 with optional PEC support all other values reserved
4 bit binary value 0 - 3 (multiplies voltages* by 10 ^
VScale)
IPScale 12...15 4 bit binary value 0 - 3 (multiplies currents* and capacities
by 10 ^ IPScale)
*Note: Except ChargingVoltage() and ChargingCurrent() values. Example: The specification version supported by a particular battery is 1.0 and all current readings are to be scaled by a factor of 10. Power readings will be scaled by the voltage factor times the current factor (10^0* 10 ^ 1) or 10 in this case. SpecificationInfo() will return 4112 (0x1010). Fuel Cell system: Returns same.
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SBDS addendum for Fuel Cell System: Initial release April 11th 2007
Appendix A. Required functions for Fuel Cell Systems
The table below shows an overview of the functions included in SES PX and standard SBDS.
Definitions used in SES PX and standard SBDS
Additional definitions used in SES PX, and standard SBDS Additional definitions used in standard SBDS
New definitions needed for Fuel Cells
Functions used in Functions needed for Functions needed for Fuel standard SBDS Fuel Cells Cells (standard definitions for (with internal (without internal smart batteries) rechargeable battery) rechargeable battery)
1 ManufacturerAccess Same Same 2 RemainingCapacityAlarm Same Same 3 RemainingTimeAlarm Same Same 4 BatteryMode BatteryMode (Bit 10) BatteryMode(Bit 10) 5 AtRate Same Same 6 AtRateTimeToFull Same N/A 7 AtRateTimeToEmpty Same N/A 8 AtRateOK Same Same 9 Temperature Internal battery only N/A (new temp call) 10 Voltage Same Same 11 Current Same Same 12 AverageCurrent Same Same 13 MaxError Same Same 14 RelativeStateOfCharge Same N/A 15 AbsoluteStateOfCharge Same N/A 16 RemainingCapacity Same Same 17 FullChargeCapacity Same Same
18 RunTimeToEmpty Same Same 19 AverageTimeToEmpty Same Same
20 AverageTimeToFull Same Same 21 ChargingCurrent Same N/A 22 ChargingVoltage Same N/A 23 BatteryStatus Same Same 24 CycleCount Same Same 25 DesignCapacity Same Same 26 DesignVoltage Same Same 27 SpecificationInfo Same Same 28 ManufactureDate Same Same 29 SerialNumber Same Same 30 ManufacturerName Same Same 31 DeviceName Same Same 32 DeviceChemistry Same+ Additional Types Same + Additional Types 33 ManufacturerData Same Same 35 DesignMaxPower New Call New Call
36 StartTime
New Call New Call 37 Total RunTime New Call New Call 38 FCtemp New Call New Call 39 FCStatus New Call New Call 40 FCMode New Call New Call 41 Aut-Soft-OFF New Call New Call 42 OptionalMfgFunction5 43 OptionalMfgFunction4
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44 OptionalMfgFunction3 45 OptionalMfgFunction2 46 OptionalMfgFunction1
Appendix B. The command set in tabular form
The following table summarizes the Smart Battery or Fuel Cell System command set. It includes the function name, code, access (r,w), and data type. For a battery or Fuel Cell system to be recognized as a Smart Battery or Fuel Cell System, it must support all the functions described by this specification.
Slave Functions Code Access Data
ManufacturerAccess 0x00 r/w word RemainingCapacityAlarm 0x01 r/w mAh RemainingTimeAlarm 0x02 r/w minutes BatteryMode 0x03 r/w bit flags AtRate 0x04 r/w mA AtRateTimeToFull 0x05 r minutes AtRateTimeToEmpty 0x06 r minutes AtRateOK 0x07 r Boolean Temperature 0x08 r 0.1°K Voltage 0x09 r mV Current 0x0a r mA AverageCurrent 0x0b r mA MaxError 0x0c r percent RelativeStateOfCharge 0x0d r percent AbsoluteStateOfCharge 0x0e r percent RemainingCapacity 0x0f r mAh FullChargeCapacity 0x10 r mAh RunTimeToEmpty 0x11 r minutes AverageTimeToEmpty 0x12 r minutes AverageTimeToFull 0x13 r minutes ChargingCurrent 0x14 r mA ChargingVoltage 0x15 r mV BatteryStatus 0x16 r bit flags CycleCount 0x17 r count DesignCapacity 0x18 r mAh DesignVoltage 0x19 r mV SpecificationInfo 0x1a r unsigned int ManufactureDate 0x1b r unsigned int SerialNumber 0x1c r number reserved 0x1d - 0x1f ManufacturerName 0x20 r string DeviceName 0x21 r string DeviceChemistry 0x22 r string ManufacturerData 0x23 r data DesignMaxPower 0x24 r data StartTime 0x25 r data TotalRuntime 0x26 r data FCTemp 0x27 r data FCStatus 0x28 r bit flags FCMode 0x29 r/w bit flags Auto-Soft_OFF 0x2a r data reserved 0x2b-0x2e OptionalMfgFunction5 0x2f r/w data 28
SBDS addendum for Fuel Cell System: Initial release April 11th 2007
reserved
OptionalMfgFunction4 OptionalMfgFunction3-1
0x30-0x3b 0x3c 0x3d-0x3f
r/w r/w
word word
29
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