RSSHow to measure the internal resistance of a battery?
Apr 15
Battery technology, Digital camera review, laptop Ibm thinkpad r50 series battery Comments Off
There are several techniques for measuring the internal resistance of a Ibm thinkpad r50 series battery , each giving slightly different results. One common method is the load test by which the DC current is applied to discharge the battery while measuring the voltage drop. The voltage divided by the current gives the internal resistance.
The CA method, also known under the term conductivity test, measures the electrochemical characteristics of a battery by applying an alternating current. The corrosion of the battery and other conditions contributing to the loss of capacity, alter the conductivity of the battery meter that can read.
Cadex uses a proprietary method for measuring the pulse of the Ibm thinkpad r50e battery internal resistance. Analyzers battery Cadex 7000 Series (Figure 7), we apply a number of pulses of charge and discharge calculating the internal resistance of the battery, according to voltage deviations. Known as the OhmTest, reading mO is obtained in five seconds without discharging the battery. The OhmTest can perform tests on a bulk quantity of batteries, a technique that is useful to vendors of cellular phones to monitor the performance of the battery before selling it. Return on security can also be checked in large part.
However, it is noted that the OhmTest gives no real conclusion about the charge status and health status of the hp pavilion dv6000 battery . The reading can vary greatly and mO is the chemical composition of the battery, the size of the cell (mAh rate), the type of item, the number of elements connected in series, and the kind of son contacts used. It is essential to have good connections to the terminal because a poor contact will give a high reading. Alligator clips and son connection is too long to avoid. A battery must have a load of at least 50% to obtain a reading mOhm significant.
Figure 1:Cadex battery analyzer 7400. The battery analyzers Series 7000 Cadex measure the internal resistance of the battery. MO readings can be made using a 5-second test on the battery or can be included in the maintenance program.
For best results, it is recommended to measure a good Ibm thinkpad r50p battery whose performance is known and use this reading as reference. A reading of mO is required for each battery. The following numbers can be used as reference for digital cellular phones:
* 150 or less per 3.6 V excellent
* 150 to 250 mO by 3.6 V good
* 250 to 350 mO by marginal 3.6V
* 350 to 500 mO by 3.6 V low
* More than 500 mO by 3.6V failure
It should be noted that the battery voltage is mentioned in relation to the reading of milliohms. A cell phone runs on electricity, which means that as the battery voltage, the greater the power requirements are reduced. In theory, a 7.2 volt battery can hold twice the reading mO a battery pack 3.6 volts, because it draws only half the current for the same power.
The OhmTest seems to work better with Li-ion, because the performance degradation is associated with corrosion of the internal element that corresponds to a high internal resistance. The performance of NiMH batteries can also be identified in large part, but the NiCd battery does not lend itself well to the test mOhm.
A low reading mO does not necessarily guarantee a high yield of the NiCd battery. Unlike the Li-ion, NiCd a high internal resistance can often be restored using the program of rehabilitation of a battery analyzer series 7000 Cadex, because the problem may be caused by memory. A successful rehabilitation is known to lower the reading mO by a factor of two or three. The complete restoration of the battery regularly.
Summary
Consumer demands have forced manufacturers to equip mobile phones battery to extend the possible duration of the conversation. However, adding more energy to a battery pack, other qualities have been neglected, especially its durability.
The family of a NiCd battery provides long service life and as might be expected, a low reading of mO. Unfortunately, this chemical composition is more popular for mobile phones because of its moderate energy density. In addition, negative publicity about the phenomenon of memory and a desire to metal toxicity have prompted customers to make other choices.
The battery is the item most expensive cell phone and the only element that is often lacking during the lifetime of the product. It is therefore prudent that manufacturers rely on the link that requires the most attention, including the battery.
About the author
Isidor Buchmann is the founder and CEO of Cadex Electronics Inc.., Richmond (Vancouver) British Columbia, Canada. Mr. Buchmann has received training in radio communications and has studied the behavior of rechargeable batteries for two decades in practice in everyday applications. Author of numerous articles and several books on battery maintenance technology, Mr. Buchmann is a well known speaker who has written technical reports and has made presentations at seminars and conferences worldwide.
About the company
Cadex Electronics Inc.. is a world leader in the field of design and manufacture of analyzers and battery chargers modern. Its successful products are used to prolong Dell xps m1730 battery life in the areas of wireless communications, emergency services, laptop computers, avionics, biochemistry, broadcasting and defense. Cadex products are sold in over 100 countries.
