acer laptop battery
A typical life of a Li-ion is 300-500 discharge/charge cycles or two years from time of manufacturing. The loss of battery capacity occurs gradually and often without the knowledge of the user. Although fully charged, the battery eventually regresses to a point where it may hold less than half of its original capacity. The function of the battery analyzer is to identify these weak batteries and “weed’ them out.
A battery analyzer can also be used to troubleshoot the cause of short runtimes. The charger may not provide a full charge or the portable device may draw more current than expected. Many of today’s battery analyzers can simulate the load signature of a digital device and verify the runtime based on the available battery capacity.
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An important feature of modern battery analyzers is its ability to read the internal battery resistance, a test that only takes a few seconds to complet. As part of natural aging, the internal resistance of a Li-ion gradually increases due to cell oxidation. The higher the resistance, the less energy the battery can deliver.
To utilize the OhmTest as a battery validation, it is essential to obtain a reference reading of a good battery with known performance. Because each battery type may be different, a reference reading will be required for each model.
A more reliable method of measuring the state-of-health of a battery is through quick-test methods. Cadex has developed a system that uses an inference algorithm to test battery capacities. The Quicktest algorithm is made battery specific by using a trend-learning algorithm that resembles the thinking process of the human brain.
The Cadex Quicktest can be performed with a charge level of between 20 and 90 percent. If the battery is insufficiently charged, or has too high a charge, the analyzer automatically applies the appropriate charge or discharge to bring the battery within testing range. Within this range, different charge levels do not affect the readings. The test lasts about two minutes and supports Li-ion/Polymer, NiMH and NiCd batteries.
The Cadex quick test is added to the Cadex 7200 and 7400 battery analyzers. These platforms feature interchangeable battery adapters that contain the battery configuration codes and matrix for the quick test.
Summary The Li-ion receives good grades in performance and reliability. Supply shortages have eased and prices have become competitive with nickel-based equivalents. As a result, more portable equipment is being fitted with the Li-ion battery.
The Li-ion has found a strong market niche with portable devices demanding small form factor. The most popular uses are mobile phones and laptop computers. Because of the aging aspect, the Li-ion is most suitable for applications with a hectic user pattern. Where the Li-ion falls short is on high current applications, such as power tools, heart defibrillators and two-way radios for public safety.
Another field where the Li-ion has proven less favorable is in applications that require only occasional battery use. On a laptop that is mostly powered by AC, for example, the Li-ion battery ages over time and the full benefit of the battery cannot be realized. High heat levels inside most laptops also cause the Li-ion to age prematurely. Field tests have revealed, however, that Li-ion is less affected by heat than NiMH.
The Lithium Ion Polymer systems are struggling to meet and surpass the performance of the Li-ion battery. High energy cost ratio limits the Li-ion Polymer to small portable devices, such as mobile phones. It is expected that once mass-produced, the Li-ion Polymer will be lower priced than the Li-ion because of simpler packaging.
This article contains excerpts from the second edition book entitled Batteries in a Portable World — A Handbook on Rechargeable Batteries for Non-Engineers. In the book, Mr. Buchmann evaluates the battery in everyday use and explains their strengths and weaknesses in laymen’s terms. The 300-page book is available from Cadex Electronics Inc. through book@cadex.com, tel. 604-231-7777 or most bookstores. For additional information on battery technology visit www.buchmann.ca.
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About the Author Isidor Buchmann is the founder and CEO of Cadex Electronics Inc., in Richmond (Vancouver) British Columbia, Canada. Mr. Buchmann has a background in radio communications and has studied the behavior of rechargeable batteries in practical, everyday applications for two decades. The author of many articles and books on battery maintenance technology, Mr. Buchmann is a well-known speaker who has delivered technical papers and presentations at seminars and conferences around the world.
About the Company Cadex Electronics Inc. is a world leader in the design and manufacture of advanced battery analyzers and chargers. Their award-winning products are used to prolong battery life in wireless communications, emergency services, mobile computing, avionics, biomedical, broadcasting and defense. Cadex products are sold in over 100 countries.
Acknowledgements The author would like to thank Mr. Ulrich Von-Sacken, Ph.D., Mr. Mark Reid and Mr. Paul Craig of NEC Moli Energy (Canada) Ltd. for their comments and suggestions.
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