Battery novices often argue that advanced battery systems are now available that offer very high energy densities, deliver 1000?charge/discharge cycles and are paper thin. These attributes are indeed achievable — unfortunately not in the same battery pack. A given apple battery may be designed for small size and long runtime, but this pack would have a limited cycle life. Another battery may be built for durability, but it would be big and bulky. A third pack may have high energy density and long durability, but would be too expensive for the commercial consumer.

Battery manufacturers are well aware of customer needs and have responded by offering battery packs that best suit the specific application. The mobile phone industry is an example of this clever adaptation. For this market, the emphasis is placed on small size and high energy density. Longevity comes in second.

The mention of NiMH on a battery pack does not automatically guarantee high energy density. A prismatic NiMH battery for a mobile phone, for example, is made for slim geometry and may only have an energy density of 60Wh/kg. The cycle count for this battery would be limited to around 300. In comparison, a cylindrical NiMH offers energy densities of 80Wh/kg and higher. Still, the cycle count of this battery will be moderate to low. High durability NiMH batteries, which are intended for industrial use and the electric vehicle enduring 1000?discharges to 80?percent depth-of discharge, are packaged in large cylindrical cells. The energy density on these cells is a modest 70Wh/kg.

Similarly, laptop battery for defense applications are being produced that far exceed the energy density of the commercial equivalent. Unfortunately, these super-high capacity Li-ion batteries are deemed unsafe in the hands of the public. Neither would the general public be able to afford to buy them.

When energy densities and cycle life are mentioned, this book refers to a middle-of-the-road commercial battery that offers a reasonable compromise in size, energy density, cycle life and price. The book excludes miracle ibm laptop battery that only live in controlled environments

Motherboard battery failure

The laptop battery is dead motherboard cause of computer failure can not be started, see dell battery.

A telephone rings, I awakened from a dream that a friend’s computer problem: press the power button, the computer and nothing happens repeatedly press the power switch is still invalid. After my initial analysis, is likely to be part of the problem of power is not enough power (power of low-grade “patent”) is a short-circuit switch, Collect a variety of tools for a pretty good idea after a friend went straight home.

Indeed, such as friends above, no matter how pressing the power switch (socket and verify that there is good access to electricity), the computer just like wood, like the “one drop of a hat.” Computer does not have any alarm sound, the motherboard does not seem to load the required voltage, power supply fan is not moving, it appears that the computer simply will not be able to power up. Open the chassis closer look at the motherboard and power supply connections and there is nothing abnormal, the power switch is also not short-circuit signs readily connect to other parts again still boot failure.

As the power of “suspects” the greatest, I have decided to replace the method used to verify, just-on-hand to have a 250W power supply, installed after the computer is still “silent”; Is this 250W power supply is Li dell latitude d520 battery, dell latitude d600 battery, dell latitude d610 battery? At this time I noted the chassis installed in the four IDE devices: two hard drives and two CD-ROM. Friends said that just to upgrade, it appears that is likely to be caused by excessive power supply, two of which I immediately unplug the power plug of equipment, try to boot, the computer has not the slightest reaction.

While I am prepared to give up when suddenly the computer’s power supply fan spinning up, then heard the sound of the hard drive self-test, the display is also slowly changing light, the computer launched! But soon, start interrupting, showing “CMOS Load Failure”, and prompted by the “F2″ key to start, according to “Del” to enter the BIOS settings, no matter, I press the F2 key to enable the system to continue to guide, but in any case can not enter the Windows XP desktop, had to restart. The press “Del” key to enter the BIOS settings, friends trying to enter a password, but directly to the, and found the time to view positioned at 0:00 on January 1, 1999, and it is clear the CMOS gd761, td347, dell inspiron 6400 battery is dead . Immediately bought a new battery into one, and all equipment connected to the boot again, the smooth startup of the computer, but still showed “CMOS Load Failure”, had no choice but to enter the BIOS settings to choose “Load BIOS SAFE DEFAULTS” and restart the smooth into the Windows XP desktop, and all the restoration unabated. In the thought that the problem has been resolved, the friends suddenly find missing floppy drive icon, the system did not identify the floppy! Is just now beginning to think that the song might touch the floppy drive connection, so no choice but to open the case more thin, but still can not see the boot floppy. Calm down, just recall the operation “Load BIOS SAFE DEFAULTS”, the floppy drive is set to the default “None”, and restart to enter the BIOS settings, was to prove my idea to come back immediately, with a floppy drive while .

Recalling the whole process, everything is small CMOS battery to blame, it seems that analysis can not be in accordance with the experience of walking, but should be adaptable, to deal with the specific environment; as to why no power CMOS, the computer can start suddenly, Although my analysis may be connected to power after the computer does not start, but the power supply has power to the motherboard, the motherboard CMOS battery to be sufficient dell inspiron e1505 battery, dell inspiron 6400 battery power to start the computer, they have taken place in front of the scene.