Compaq Lithium-ion battery user manual

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Lithium-ion battery technology:
Getting the most from Smart Batteries


Abstract.............................................................................................................................................. 2
Introduction......................................................................................................................................... 2
Lithium-ion batteries..............................................................................................

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Abstract This paper tells HP notebook users how to get the most out of their lithium-ion rechargeable batteries in terms of run time and lifespan. Detailed in this document are important facts about Li-Ion batteries, information about HP Smart Battery Technology, and proper battery care practices. Introduction One of the most common questions asked by notebook computer users is "How long will the battery last?" The answer is not simple. Users inevitably discover that battery run time varie

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Battery cycle life Battery cycle life is the total number of discharge-charge cycles (Figure 1) a battery yields before it can no longer hold a useful amount of charge. Estimating the cycle life of a rechargeable Li-Ion battery is difficult because cycle life is affected by the average operating temperature of the battery and its energy discharge rate. Basically, higher temperatures and higher energy discharge rates decrease battery cycle life. The operating temperature of the battery depen

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Warranty period HP provides a 12-month warranty for Li-Ion batteries. The warranty period is based upon the expectation that the battery will deliver 80% of its initial capacity after 300 cycles at low to moderate power loads. High power loads may cause a battery to reach 80% of initial capacity in less than the 12-month warranty period. Li-Ion batteries will continue to operate below the 80% capacity threshold; however, the capacity (run time) delivered between charges will continue to dec

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Smart Battery Technology Estimating battery run time is further complicated by the inaccuracy of the system that monitors and reports the battery charge status to the user. Some notebooks estimate the battery charge state based on manufacturer testing of the specific product model with a particular configuration. This method is inaccurate when another battery with a different state-of-charge is inserted, because charge status of each battery is estimated based on its history in the system.

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Battery care practices After reading the information presented in this paper, users should be aware of conditions that negatively impact battery run time and lifespan. In summary: • Li-Ion battery cells suffer gradual, irreversible capacity loss with each discharge-charge cycle. Such aging occurs more rapidly as temperature and discharge loads increase. • The self-discharge rate of a Li-Ion battery is higher if the battery is left in an unpowered notebook. • During prolonged storage or non

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For more information For additional information, refer to the resources detailed below. Resource description* Web address Commercial Notebook ftp://ftp.compaq.com/pub/supportinformation/papers/155l-0601a-wwen.pdf Batteries: Performance Optimization white paper contains instructions on calibrating Li-Ion batteries Smart Battery System http://www.sbs-forum.org/ Implementers Forum *The information provided by these resources may not apply to all systems. © Copyright 2004 Hewlett-P