Digital Notebook Battery
User's Guide
Part Number: ER-NBBTR-BM. A01
Digital Equipment Corporation
User's Guide
Digital Notebook Battery
.
July 1996
The information in this document is subject to change without notice and should not be construed as a commitment by Digital Equipment Corporation.
Digital Equipment Corporation assumes no responsibility for any errors that might appear in this document.
The software described in this document is furnished under a license and may be used or copied only in accordance with the terms of such license. No responsibility is assumed for the use or reliability of software or equipment that is not supplied by Digital Equipment Corporation or its affiliated companies.
Any changes or modifications made to this equipment may void the user's authority to operate this equipment.
This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:
Reorient or relocate the receiving antenna
Increase the separation between the equipment and receiver
Connect the equipment into an outlet on a circuit different from that to which the receiver is connected
Consult the dealer or an experienced radio/TV technician
for help
Ó 1996 Digital
Equipment Corporation. All Rights Reserved.
DEC, HiNote, HiNote VP, and the Digital logo are trademarks of Digital Equipment Corporation.
Contents
1 General Battery Information 1 Introduction 1 Important! 1 Typical Characteristics 2 Power Saving Habits 2 Storing Your Battery 4 Replacing Batteries 42 NiMH (Nickel-Metal Hydride) Batteries 5 Introduction 5 Memory Effect 6 Forming the Battery to Minimize Memory Effect 73 LiIon (Lithium-Ion) Batteries 9 Introduction 94 Battery Performance 11 Introduction 11 Performance Tests 11
The length of time that your system can be operated on battery power directly depends on your operating habits, system characteristics, milliamp/hour capacity of the battery, and battery technology (nickel-metal hydride - NiMH or lithium-ion - LiIon).
This guide provides information on how to maximize your battery's life span and run time. Also provided in this guide is information on how you can expect your notebook's battery to perform under diverse operating conditions.
No matter what type of battery technology your notebook incorporates, even a new battery may not be fully charged at the time of purchase. This is because all batteries lose some of their charge during storage, even the "storage" time before a notebook system is purchased. Therefore, before using battery power for the first time, you should make sure your battery is fully charged.
If you have a NiMH battery, this means you must "form" the battery (refer to the Nickel-Metal Hydride Batteries section of this guide).
If you have a lithium-ion battery, simply charge the battery before using it for the first time.
All batteries have a limited life span. A battery's life span is measured by the number of charging and draining cycles it can undergo before it can no longer be charged. The amount of time that your system can be operated from battery power before the battery is exhausted is referred to as battery run time.
When using your Digital notebook on battery power, it is important to develop good power saving habits to help optimize battery run time. When all power management settings are enabled, and aggressive power management techniques are used, battery run times at the high end of the range specified in your user documentation are possible. Your notebook is equipped with several built-in power conserving features that can be configured from the BIOS setup.
By enabling these features, you will receive the longest battery run time possible depending on your operating requirements and habits. Refer to the BIOS Setup section in your User's Guide for complete details. You can further extend the time that the notebook can be run from battery power by practicing the following power conserving habits.
If you need to momentarily stop using the notebook, immediately press the key combination to enter Standby mode (refer to your User's Guide for the correct key combination). The system will turn off the LCD and spin down the hard disk drive (HDD) to conserve some battery power. Touchpad, trackball, or keyboard activity returns the system to normal operation.
If you need to stop using the notebook for longer than a few moments, press the Suspend/Resume (Power) button or, if you own a HiNote, HiNote Ultra, or HiNote Ultra II, you can also close the lid. Either action suspends the system to conserve battery power and increase run time. In suspend mode all high power consuming items (LCD, HDD, CD-ROM, FDD, and CPU) are turned off and open applications and data are stored in memory. Press the Suspend/Resume (Power) button to return the system to where you stopped.
The brighter the LCD display screen, the shorter the battery run time. Avoid setting the screen brightness higher than necessary. This can extend battery run time between 10 and 30 minutes.
The floppy disk and CD-ROM drives are motor-driven and consume a lot of battery power. Playing an audio CD on your system while using battery power can reduce your battery run time to as little as 30 minutes. Conserve power by using these devices as little as possible during battery operation.
PC (PCMCIA) Cards also tax your battery power, significantly reducing run time. A PCMCIA modem or PCMCIA ATA Hard Drive plugged in to a PCMCIA slot, even if not in use, can reduce battery run time by 11 to 18 minutes. When using the notebook on battery power, use PC Cards as little as possible, and when finished using your PC Card, eject it from the PC Card slot.
The following are some power conserving features provided in the BIOS setup program. Refer to the BIOS Setup section in your User's Guide for details.
Maximum Battery Life -- This setting can extend battery run time significantly when the system will have light use with repeated pauses that last several minutes (Standby and Suspend automatically activate in these instances). This setting is a combination of several power settings. You can also select them individually depending on your computing needs and which notebook you own (refer to the BIOS Setup section in User's Guide for more details).
Half Speed -- This setting allows you to choose the speed of the CPU. Choosing 50% speed improves battery life, especially during CPU intensive tasks.
PCMCIA Socket Power in Suspend = Off (Battery Operation) -- This setting extends battery run time by turning off power to the PCMCIA socket in Suspend. (this feature is not available on the HiNote VP notebook model.)
IR= Off/Disabled -- This setting extends battery run time by turning off power to the IR sensor.
Batteries slowly lose their charge, even when the notebook is in the power off mode. If you own the HiNote Ultra model, do not leave a depleted battery in the notebook for more than 30 days. It will continue to drain to the point where it cannot be recharged. When batteries are stored outside the notebook they hold their charge much longer. So, if your batteries will not be used for an extended period of time, store them fully charged, outside the system.
Digital recommends that you charge even fully charged stored NiMH batteries at least every six months and stored LiIon batteries every 90 days. If you have any backup batteries, remember to periodically recharge them as well.
Of course the ideal way to prevent your notebook battery from losing its charge during extended non-use is to keep your notebook plugged into ac power using a surge protector to avoid damage from power surges.
When replacing batteries, use only Digital qualified batteries that are compatible with the notebook computer's electrical requirements and charging circuitry.
Although LiIon battery technology is very stable,
there is still a danger of explosion if a LiIon battery is incorrectly
replaced with a battery not qualified by Digital Equipment Corporation.
LiIon batteries must be replaced with the equivalent battery
qualified by Digital. Consult your authorized Digital notebook
provider if you have questions about replacement batteries.
NiMH batteries appear in many different kinds of devices, such as cellular phones and camcorders. NiMH technology offers users notable advances over its predecessor, nickel-cadmium (NiCd) technology.
Digital has incorporated NiMH battery technology into the design of the HiNote. This technology supports 30% more charge capacity than NiCd batteries, providing users with significantly more run time. Containing no toxic metals, NiMH batteries do not require any special disposal procedures, making them extremely environmentally friendly.
Your battery not only powers the notebook, but also significantly affects system performance. It is therefore important to take proper care of your NiMH battery. When a battery is not properly cared for, both its life span and runtime will decline.
A NiMH battery in poor or declining condition may begin to exhibit characteristics of "memory effect." A memory effect will occur when a user frequently charges the battery before it is fully drained. For example, if you use the battery for 20 minutes at a time and then recharge it, the battery will tend to "remember" that it only needs to operate 20 minutes per charge. As a result, during the charging process the declining battery will only receive a portion of its charge capacity. The declining battery will also exhibit some characteristics of a fully charged battery. For example, during charging, the battery temperature will rise, prompting the system to stop charging.
The memory effect also has a direct impact on the battery's life span. NiMH batteries have a typical life (charge/drain cycles) of up to 800 cycles. If the battery is used an average of 30 minutes per cycle, you can expect a total life of 400 hours. If you use the battery 3 hours per cycle, you can expect a total life of 2,400 hours. Therefore, it is advantageous to use the battery as much as possible during each cycle.
The battery charge gauge (on the LCD Status Display) may give inaccurate readings when the battery is suffering memory effect. When the battery temperature has risen as part of memory effect, the battery charge gauge may assume that the battery is more charged than it actually is and display the full-charge battery icon.
The battery charge gauge may also give inaccurate readings after a "fresh" battery is swapped in without turning off the system. This occurs because the battery charge gauge readings are based on a new estimate, not having tracked the newly inserted battery charge or discharge amounts. The gauge is not reporting only the condition of the new battery. As a result, the battery charge gauge may report a higher or lower charge than is accurate.
In either of these situations, a full-charge battery icon may display when the battery is actually only partially charged and the system may suspend without warning due to a depleted battery. This can result in the illusion of reduced battery run time. Uncertain as to the cause of the problem, some users will send their notebook to product repair centers, resulting in unwanted downtime. You can receive a more accurate battery charge reading after swapping in a fresh battery by rebooting the system. This action has the effect of "resetting" the battery charge gauge. The following section describes how to minimize the more far reaching problem of memory effect.
In attempts to prevent the memory effect, it may not always be practical to continuously use your notebook until the battery drains to its minimum level. As a solution, Digital recommends that users periodically "form" or condition the battery. "Forming" allows the battery to achieve its maximum life span as well as providing the maximum battery run time possible, depending upon your requirements and operating habits.
When a battery is formed, it is put through a series of charging and draining cycles. A battery that has been formed can be charged to its maximum capacity. As a result, a formed battery will perform better and last longer than a battery that has not been formed.
It will take approximately 10.5 hours to complete the battery forming process.
In power off mode, it takes approximately 1.5 hours to fully charge the battery. Depending on your work habits, the battery will reach a low state after approximately 3 hours of use. Forming requires three charging sessions (4.5 hours) and two draining sessions (6 hours)--a total of 10.5 hours.
Software is available to help you completely drain the battery. Much of this software is available in shareware form. Performance varies from program to program; however, one application that has proven effective is "Rundown." Without this type of software, you can expedite the battery draining process by:
Proven first in cameras and then in camcorders, Digital is pioneering lithium-ion (LiIon) battery technology for the mobile computer user. Digital uses LiIon batteries that are extremely light weight, a highly sought after feature in the portable computing industry.
As a result of its high charge density and voltage, the size of a Digital LiIon battery is minimal, helping to meet the overall system goal of portability while enhancing ergonomics. LiIon batteries have a solid composition that allows the batteries to be fashioned in a variety of shapes, suiting the lowest profile requirement. Digital took advantage of this characteristic in the HiNote Ultra system where the battery is hinged to support the notebook at an angle. As a result, Digital engineers are able to provide users with a more ergonomically designed typing surface for greater comfort.
LiIon batteries offer a higher charge density than NiMH batteries. Thus, when comparing a LiIon battery to a NiMH battery of the same weight, the LiIon battery will have significantly longer run time.
LiIon batteries also have a longer life span, averaging
1,000 complete charge/discharge cycles. In actual use, the number
is larger due to the fact that most users will not fully discharge
the battery. Unlike the NiMH battery, there is no need to be concerned
with fully discharging the battery before charging it again since
LiIon technology is not susceptible to memory effect.
Your manual and other related documents contain information on what you should be able to achieve for battery run time. These numbers may have been higher than what some users actually experienced. The reason for the difference is varying user operating requirements and habits.
A battery's performance is directly related to how the notebook is operated. For example, frequent use of high energy draining components such as the floppy diskette drive (FDD) and PCMCIA card sockets will significantly shorten the battery's run time. The battery run times represented in your documentation were derived from tests under optimal operating conditions: full use of advanced power management features in the BIOS Setup Program, full use of the notebook's suspend/resume feature, lower LCD brightness, and minimum use of components such as the FDD and PCMCIA card sockets.
Digital performs a number of battery performance tests to determine how our batteries perform under various conditions. The results of these tests help us validate the expected battery run times published in your user documentation, and also help us better understand how our customers might tax battery resources in our notebook computers. Digital has utilized both internal and external testing sites to subject the HiNote Ultra II and HiNote VP to a series of tests over hundreds of hours of use.
The VeriTest Cross Country, Zdigit, and WinDrain battery performance tests are commonly used in the industry. Each test is typically a high or medium activity test that does not take advantage of aggressive power management features. such as, LCD turn-off, HDD spin downs, and time in Standby or Suspend. Therefore, the numbers reported by these tests will always be lower than what the typical user should experience.
The VeriTest Cross Country battery performance profile is specifically designed to simulate the use of a notebook computer on a cross-country airplane flight by a typical executive user.
The WinDrain test, also performed at Ziff Davis, is a high activity test that does not allow any power management features to be used. The battery is constantly used.