1. Software Update

   • The MacBook Pro´s OS X operating system includes a component called “Software Update.” By default, Software Update is configured to check for new software updates via the Internet on a weekly basis. Software Update checks for updates to individual Apple software applications, such as iTunes and QuickTime, as well as for updates to the OS X operating system.

   Configuration

   • Mac OS X´s System Preferences menu includes an icon that allows you to access the settings for Software Update. As well as allowing you to change the frequency of update checking to daily or weekly, you can also disable the Software Update functionality using these options. It is unwise to do this, as you may miss important security patches for your MacBook Pro. However, sometimes disabling updates temporarily may be necessary, such as when you are using an expensive mobile Internet connection.

   Installation

   • When your MacBook Pro has downloaded updates to your computer, a dialog box appears to request that you install them. Before installing the updates, you can view information about each of them, which includes details of whether you will need to restart your computer to complete the installation. If it is not convenient to install updates when the dialog box appears, you can click the “Not now” button to postpone the updates.

     If you prefer not to wait until Software Update automatically updates based on its scheduled settings, you can manually trigger the Software Update utility, by clicking “Software Update” from the Apple menu.

   Recommendation

   • It is always best to keep on top of software updates for your MacBook Pro, so that the computer runs at its best and is secure from the most recently discovered vulnerabilities. Leave the system configured to update on at least a weekly basis, and ensure you run Software Update manually once connected to your normal Internet connection if you have cause to disable it temporarily.

   • read more:

   Apple MacBook 13.3 inch Aluminum Unibody MB466LL/A MB467LL/A A1280,

   APPLE A1045 A1078,

   PowerBook G4 15-inch Aluminum series,

   Apple MacBook Pro 13″ Series ,MacBook 13″ MB467CH/A

Windows 7 is more energy-efficient than Vista

Overall, when users watch DVD through the laptop when the laptop battery life under Windows7 be increased by 10% to 20%. Panabeike said it was a great performance.

Last week, has been reported that the use of Windows7 operating system, Internet this Toshiba laptop battery life decreased by 1 / 3. Focus on the laptop reported “Laptop” magazine this week that Toshiba, the Internet has been tested, the results of the use of the Internet after Windows7 reduce the time of the battery life of 2.5 hours. In the XP system, the battery life of 9 hours, 24 minutes, while Windows7 only 6 hours 53 minutes.

According to Toms Hardware site testing, the XP system, the Acer AcerAspireOne access to this Sony laptop battery life is 8 hours and 28 minutes, while in Windows 7, under 5 hours, 54 minutes, the same reduction of 2.5 hours.

The Dell XPS M1330 is designed for those that want power on the go. If you’re also fashion conscious and like to standout in a crowd, the looks of the XPS M1330 will help you in that area too. Sleek design coupled with a portable form factor and powerful components come together to make for a compelling notebook.

Build and Design

Our pre-production XPS M1330 as equipped:

Unlike the bulky, unattractive 12-inch Dell XPS m1210 with li-ion xps M1210 battery , the M1330 has clearly been built with an emphasis on good looks and clean lines, ditching the earlier model’s cumbersome, rotating Web cam and thick chassis. The system is slightly wedge shaped, going from 0.87 inch in the front to 1.3 inches in the rear. At less than four pounds, it’s one of the lightest 13-inch laptops we’ve seen–nearly a full pound lighter than the popular yet hefty 13-inch Apple MacBook, and a touch lighter than the 12-inch XPS M1210 with powerful dell xps m1210 battery .

The keyboard tray is brushed silver with black accents, while the lid is available in black, white, or red. Our review unit had the matte-red finish (Dell calls it Crimson Red), which looks great, but more color options (as with the newly revamped Inspiron line of laptops) would have been welcome.

Dell manages to squeeze a good number of extras onto the keyboard tray, including touch-sensitive controls for volume and media playback, an eject button for the slot-loading DVD drive, and a quick-launch button for Dell’s proprietary Media Direct software. The biggest drawback we found with the M1330’s design was the tiny, 2.75-inch touchpad, which we found to be particularly frustrating given the fact that there’s plenty of room on the wrist rest for a bigger pad.

You will love:Dell XPS M1330 has 2 megapixel camera sensor resolution which is higher in comparison with similar priced notebooks. Dell XPS M1330 has only 4-pound weight,9 cells dell xps M1330 battery. Price comes upto $715 this notebook has great features for the money.

You will hate:Screen size 13.3-inch is somewhat smaller than some similarly priced notebooks. This notebook has a modest 2.0 GHz CPU speed. Graphics-intensive applications will certainly hinder performance on a system that relies on relies shared video RAM.

Summary

There are very few 13-inch laptops on the market that bring the caliber of hardware and performance of the Dell XPS M1330. We’re getting a glimpse of the future in ultraportable power with the Dell XPS M1330 battery .Its battery is as good as inspiron e1505 battery . Game-capable graphics, blazing processor speed, and a pile of RAM all packed into a lovely chassis that’s as comfortable to carry as a hardback airport romance novel. Despite the extra cash you’ll shell out, we think the Dell XPS M1330 is the clear choice over other cheaper, less powerful notebooks.

Legend car industry, car head FLYER Wang Chuanfu build electric car was already present on the surface, as a matter of iron nails. Yesterday, reporter learned from deputy general manager of BYD Automobile Co., Ltd. Wang permanent Department confirmed the first batch of 200 electric vehicles will soon BYD line , and the streets as taxis in Shenzhen debut. He said that the first batch of 200 BYD electric cars in the trial after the process of improving and perfecting with Pavilion dv4000 battery inspiron 5150 battery Inspiron E1705 battery, the production will soon be, available for sale.

BYD to take the lead private enterprises to create the first of a pure electric vehicle, the matter of China’s car industry is no doubt a major miracle. It also triggered a lot of suspense. The feasibility of electric cars from their own point of view, the core issue of debate lies in batteries, electric bicycle very well-known to describe the problem to Thinkpad T30 battery IBM 40Y9797 EVO N410C battery.

A few years ago, appeared in the market for electric bicycles, pedal the liberation of the suffering consumers, it also highlights a number of electric vehicles of its own problems: First, the use of rechargeable batteries for electric vehicles as fuel for a major common problem is lack of motivation, Start slowly and accelerate slowly Apple A1078; Second, rechargeable batteries are usually “short-lived”; Third, the easy circuit failure, often the way “off.” As a result of these widespread problems, the electric bike several times in the market perform “a flash in the pan”, the market is very slow to start. Small electric bicycle laptop battery in resolving the issue even come a long way so difficult, as a “monster” of BYD electric cars will be going through the same test it? This will be the BYD electric vehicle facing the first suspense.

Second, electric cars cost more than conventional gasoline cars, electric cars today is also difficult to mass commercial production of one of the main obstacles. While BYD electric cars that the cost of its single laptop battery only 4 million, but the use of rechargeable batteries matching the cost and determine the vulnerability of the overall consumption of electric vehicles the cost is not a small sum. BYD electric cars will be how to effectively address the rechargeable dell laptop battery life and cost issues? This is the second largest of its suspense face.

Third, although the electric car is environmentally-friendly vehicle, but the Apple laptop battery itself is not environmental protection, the use of complex chemical raw materials created by the battery once the waste, recycling will become difficult to deal with the toxic chemical waste, scrap battery recycling has become the face of environmental protection a major issue. BYD electric cars, even if the realization of the mass production and mass consumption, and if it failed to address the concentration of waste battery recycling issues,

The environmental protection departments may not be easily released. In short, dare to eat a crab BYD car while the first one to create electric vehicles with Thinkpad X40 battery Latitude C600 battery and at the same time can be said to have produced a series of new questions. 1 China’s first electric vehicle will go from here?

Thus our batteries fall short of providing our laptops with the required energy more than often. The reason is simple. We don’t know how to use it judiciously to elongate its life. Follow the following lines on this electronic blog so you don’t fall prey to such a situation.

Use Power-saving Setting : Every laptop has its power-saving setting in its control panel. Using this setting helps to stop the unwanted use of various parts such as hard drive, screen etc. Also reducing the time limit for your screensaver around one minute helps a lot.

No Externals : Using externals laptop accessories such as, mouse, keyboards, and entertainments appliances such as DVDs and CD playrers hamper the life of a battery. It is better to use the inbuilt keyboard and touchpad. Also, watch a movie directly from the hard drive only. Also using headphones saves more energy than using a speaker.

Kick On The Backlight : There are times when you don’t need the backlight at all such as while downloading a file etc. So you better switch it off.

Switch off Bluetooth : It tends to switch on when you start your laptop computers. Thus it brings enough load on the battery. So, switch it off if you are not using it.

Say Bye To Wi-Fi : The same damage can be done by a Wi-Fi connection too. So better disconnect it when not in use.

Set Your Screen : Using your screen in the right way can save your battery for long. You can do it by minimizing the brightness, color composition and resolution to the maximum.

Regular Defragmentation : Regular defragmentation of the hard disk has two obvious benefits. First, it speeds up your processor and secondly, it keeps all the files in regular order which saves time while locating a file. Thus helping you save the battery.

Close Unnecessary Processes : You are not required to use all the processes while operating your laptop. So close down all the processes which bring an unwanted load on the laptop. Vistas needs no more than 48 switched-on processes for a smooth operation. Also do you know that you can use Microsoft XP closing down all but 18 processes?

Clean It : You are not supposed to give it a bath in the tub. Rather you keep cleaning, using a cotton ball, the metal contacts of your battery almost once in a month. Removing the dirt improves the flow of energy.

Use It or Lose It : Never leave a fully charged battery unused for weeks. Use almost every week. It is just like warm up session for a battery.

Lithium is the lightest of all metals, has the greatest electrochemical potential and provides the largest specific energy per weight. Rechargeable batteries with lithium metal on the anode (negative electrodes)* could provide extraordinarily high energy densities; however, it was discovered in the mid 1980s that cycling produced unwanted dendrites on the anode. These growth particles penetrate the separator and cause an electrical short. When this occurs, the cell temperature rises quickly and approaches the melting point of lithium, causing thermal runaway, also known as “venting with flame.” A large number of rechargeable metallic lithium batteries sent to Japan were recalled in 1991 after a battery in a mobile phone released flaming gases and inflicted burns to a man’s face.

The inherent instability of lithium metal, especially during charging, shifted research to a non-metallic solution using lithium ions. Although lower in specific energy than lithium-metal, Li‑ion is safe, provided cell manufacturers and battery packers follow safety measures in keeping voltage and currents to secure levels. Read more about Protection Circuits. In 1991, Sony commercialized the first Li‑ion battery, and today this chemistry has become the most promising and fastest growing on the market. Meanwhile, research continues to develop a safe metallic lithium battery.

The specific energy of Li‑ion is twice that of NiCd, and the high nominal cell voltage of 3.60V as compared to 1.20V for nickel systems contributes to this gain. Improvements in the active materials of the electrode have the potential of further increases in energy density. The load characteristics are good, and the flat discharge curve offers effective utilization of the stored energy in a desirable voltage spectrum of 3.70 to 2.80V/cell. Nickel-based batteries also have a flat discharge curve that ranges from 1.25 to 1.0V/cell.

In 1994, the cost to manufacture Li-ion in the 18650** cylindrical cell with a capacity of 1,100mAh was more than $10. In 2001, the price dropped to $2 and the capacity rose to 1,900mAh. Today, high energy-dense 18650 cells deliver over 3,000mAh and the costs have dropped further. Cost reduction, increase in specific energy and the absence of toxic material paved the road to make Li-ion the universally accepted battery for portable application, first in the consumer industry and now increasingly also in heavy industry, including electric powertrains for vehicles.

In 2009, roughly 38 percent of all batteries by revenue were Li‑ion. Li-ion is a low-maintenance battery, an advantage many other chemistries cannot claim. The battery has no memory and does not need exercising (deliberate full discharge) to keep in shape. Self-discharge is less than half that of nickel-based systems. This makes Li‑ion well suited for fuel gauge applications. The nominal cell voltage of 3.60V can directly power cell phones and digital cameras, offering simplifications and cost reductions over multi-cell designs. The drawbacks are the need for protection circuits to prevent abuse, as well as high price.

Types of Lithium-ion Batteries

Similar to the lead- and nickel-based architecture, lithium-ion uses a cathode (positive electrode), an anode (negative electrode) and electrolyte as conductor. The cathode is a metal oxide and the anode consists of porous carbon. During discharge, the ions flow from the anode to the cathode through the electrolyte and separator; charge reverses the direction and the ions flow from the cathode to the anode. Figure 1 illustrates the process.

Figure 1: Ion flow in lithium-ion battery. When the cell charges and discharges, ions shuttle between cathode (positive electrode) and anode (negative electrode). On discharge, the anode undergoes oxidation, or loss of electrons, and the cathode sees a reduction, or a gain of electrons. Charge reverses the movement.

Li‑ion batteries come in many varieties but all have one thing in common — the catchword “lithium-ion.” Although strikingly similar at first glance, these batteries vary in performance, and the choice of cathode materials gives them their unique personality.

Common cathode materials are Lithium Cobalt Oxide (or Lithium Cobaltate), Lithium Manganese Oxide (also known as spinel or Lithium Manganate), Lithium Iron Phosphate, as well as Lithium Nickel Manganese Cobalt (or NMC)*** and Lithium Nickel Cobalt Aluminum Oxide (or NCA). All these materials possess a theoretical specific energy with given limits. (Lithium-ion has a theoretically capacity of about 2,000kWh. This is more than 10 times the specific energy of a commercial Li-ion battery.)

Sony’s original lithium-ion battery used coke as the anode (coal product). Since 1997, most Li‑ion manufacturers, including Sony, have shifted to graphite to attain a flatter discharge curve. Graphite is a form of carbon that is also used in the lead pencil. It stores lithium-ion well when the battery is charged and has long-term cycle stability. Among the carbon materials, graphite is the most commonly used, followed by hard and soft carbons. Other carbons, such as carbon nanotubes, have not yet found commercial use. Figure 2-8 illustrates the voltage discharge curve of a modern Li-ion with graphite anode and the early coke version.

Figure 2: Voltage discharge curve of lithium-ion A battery should have a flat voltage curve in the usable discharge range. The modern graphite anode does this better than the early coke version. Courtesy of Cadex

Developments also occur on the anode and several additives are being tried, including silicon-based alloys. Silicon achieves a 20 to 30 percent increase in specific energy at the cost of lower load currents and reduced cycle life. Nano-structured lithium-titanate as an anode additive shows promising cycle life, good load capabilities, excellent low-temperature performance and superior safety, but the specific energy is low.

Mixing cathode and anode material allows manufacturers to strengthen intrinsic qualities; however, enhancing one attribute may compromise another. Battery makers can, for example, optimize the specific energy (capacity) to achieve extended runtime, increase the specific power for improved current loading, extend service life for better longevity, and enhance safety to endure environmental stresses. But there are drawbacks. A higher capacity reduces the current loading; optimizing current loading lowers the specific energy; and ruggedizing a cell for long life and improved safety increases battery size and adds to cost due to a thicker separator. The separator is said to be the most expensive part of a battery.

Manufacturers can attain a high specific energy and low cost relatively easily by adding nickel in lieu of cobalt, but this makes the cell less stable. While a start-up company may focus on high specific energy to gain quick market acceptance, safety and durability cannot be compromised. Reputable manufacturers place high integrity on safety and longevity.

Table 3 summarizes the characteristics of Li-ion with different cathode material. The table limits the chemistries to the four most commonly used lithium-ion systems and applies the short form to describe them. The batteries are Li-cobalt, Li-manganese, Li-phosphate and NMC. NMC stands for nickel-manganese-cobalt, a chemistry that is relatively new and can be tailored for applications needing either high capacity or high loading capabilities. Lithium-ion-polymer is not mentioned as this is not a unique chemistry and only differs in construction. Li-polymer can be made in various chemistries and the most widely used format is Li-cobalt.

Table 3: Characteristics of the four most commonly used lithium-ion batteries
Specific energy refers to capacity (energy storage); specific power denotes load capability.

¹ NMC, NCM, CMN, CNM, MNC and MCN are basically the same. The stoichiometry is usually Li[Ni(1/3)Co(1/3)Mn(1/3)]O2. The order of  Ni, Mn and Co does not matter much.

² Application and environment govern cycle life; the numbers do not always apply correctly.

³ A fully charged battery raises the thermal runaway temperature, a partial charge lowers it.

Never was the competition to find an ideal battery more intense than today. Manufacturers see new applications for automotive propulsion systems, as well as stationary and grid storage, also knows as load leveling. At time of writing, the battery industry speculates that the Li-manganese and/or NMC might be the winners for the electric powertrain.

Industry’s experience has mostly been in portable applications, and the long-term suitability of batteries for automotive use is still unknown. A clear assessment of the cycle life, performance and long-term operating cost will only be known after having gone through a few generations of batteries for vehicles with electric powertrains, and more is known about the customers’ behavior and climate conditions under which the batteries are exposed. Table 4 summarizes the advantages and limitations of Li-ion.

Table 4: Advantages and limitations of Li‑ion batteries

*          When consuming power, as in a diode, vacuum tube or a battery on charge, the anode is positive; when withdrawing power, as in a battery on discharge, the anode becomes negative.

**       Standard of a cylindrical Li-ion cell developed in the mid 1990s; measures 18mm in diameter and 65mm in length; commonly used for laptops. Read more about Battery Formats.

***     Some Lithium Nickel Manganese Cobalt Oxide systems go by designation of NCM, CMN, CNM, MNC and MCN. The systems are basically the same.

Firefly Energy

The composite plate material of the Firefly Energy battery is based on a lead acid variant that is lighter, longer living and has higher active material utilization than current lead acid systems. The battery includes foam electrodes for the negative plates, which gives it a performance that is comparable to NiMH but at lower manufacturing costs. Design concerns include microtubule blockage through crystal growth during low charge conditions. In addition, crystal expansion causes a reduction of the surface area, which will result in lower capacity with aging. Pricing is also a concern. It currently costs about $450 to manufacture a Firefly battery as opposed to $150 for a regular lead acid version. Firefly Energy is a spin-off of Caterpillar and went into bankruptcy in 2010.

Altraverda Bipolar

Similar to the Firefly Energy battery, the Altraverda battery is based on lead. It uses a proprietary titanium sub-oxide ceramic structure, called Ebonex^®, for the grid and an AGM separator. The un-pasted plate contains Ebonex^® particles in a polymer matrix that holds a thin lead alloy foil on the external surfaces. With 50–60Wh/kg, the specific energy is about one-third larger than regular lead acid and is comparable with NiCd. Based in the UK, Altraverda works with East Penn in the USA, and the battery is well suited for higher voltage applications.

Axion Powe

The Axion Power e3 Supercell is a hybrid battery/ultracapacitor in which the positive electrode consists of standard lead dioxide and the negative electrode is activated carbon, while maintaining an assembly process that is similar to lead acid. The Axion Power battery offers faster recharge times and longer cycle life on repeated deep discharges than what is possible with regular lead acid systems. This opens the door for the start-stop application in micro-hybrid cars. The lead-carbon combination of the Axion Power battery lowers the lead content on the negative plate, which results in a weight reduction of 30 percent compared to a regular lead acid. This, however, also lowers the specific energy to 15–25Wh/kg instead of 30–50Wh/kg, which a regular lead acid battery normally provides.

CSIRO Ultrabattery

The CSIRO Ultrabattery combines an asymmetric ultracapacitor and a lead acid battery in each cell. The capacitor enhances the power and lifetime of the battery by acting as a buffer during charging and discharging, prolonging the lifetime by a factor of four over customary lead acid systems and producing 50 percent more power. The manufacturer also claims that the battery is 70 percent cheaper to produce than current hybrid electric vehicle (HEV) batteries. CSIRO batteries are undergoing road trials in a Honda Insight HEV and show good results. Furukawa Battery in Japan licensed the technology. The CSIRO battery is also being tested for start-stop applications in micro-hybrid cars to replace the lead acid starter battery. This battery promises extended life when exposed to frequent start-stop conditions and is able to take a fast charge.

EEStor

This is the mystery battery/ultracapacitor combination that receives much media attention. The battery is based on a modified barium titanate ceramic powder and claims a specific energy of up to 280Wh/kg, higher than lithium-ion. The company is very secretive about their invention and releases only limited information. Some of their astonishing claims are: One-tenth of the weight of a NiMH battery in a hybrid application, no deep-cycle wear-down, three- to six-minute charge time, no hazardous material, similar manufacturing costs to lead acid, and a self-discharge that is only 0.02 percent per month, a fraction of that of lead acid and Li-ion.

The first lead acids were flooded, and during the mid 1970s, the sealed or maintenance-free version appeared. The liquid electrolyte is transformed into moistened separators and the sealed enclosure fitted with safety valves to control venting of gas during charge and discharge. The sealed lead acid has the advantage that it can operate in any position.

Maintenance-free Lead Acid

Driven by the advantage of being maintenance-free, two types emerged: the sealed lead acid (SLA), also known as gel cell, and the valve-regulated lead acid (VRLA). The systems are similar and no scientific convention exists as to what constitutes an SLA and a VRLA. (Engineers may argue that the term “sealed lead acid” is a misnomer because no lead acid battery can be totally sealed.)

We identify SLA as having a capacity range up to 30Ah. Typical uses are personal UPS for PC backup, small emergency lighting units, ventilators for healthcare patients and wheelchairs. Known for its economical price, dependable service and minimal maintenance, the SLA is the preferred choice for biomedical and healthcare instruments in hospitals and retirement homes. The VRLA battery is larger and mostly used for stationary applications. Capacities range from 30Ah to several thousand Ah and make up larger UPS systems. These may be cellular repeater towers, cable distribution centers, Internet hubs and utilities, as well as power backup for banks, hospitals, airports and military installations.

Unlike the flooded lead acid, both the SLA and VRLA are designed with a low over-voltage potential to prohibit the battery from reaching its gas-generating potential during charge. Excess charging causes gassing and water depletion. Consequently, the SLA and VRLA can never be charged to their full potential.

Applying the right voltage limit when charging lead acid systems is critical and any voltage level is a compromise. A low voltage may shelter the battery but this causes poor performance and a buildup of sulfation on the negative plate. A high voltage limit improves performance but it promotes grid corrosion on the positive plate. The corrosion is permanent and cannot be reversed. Temperature changes the voltage threshold.

Lead acid does not lend itself to fast charging and a fully saturated charge requires 14 to16 hours. The battery must always be stored at full state-of-charge. Dwelling on low charge causes sulfation, a condition that robs the battery of performance. The addition of carbon on the negative electrode helps to alleviate some of these problems but lowers the specific energy.

Lead acid is not subject to memory, but correct charge and float voltages are important to achieve a long life. Charge retention is best among rechargeable batteries, and while NiCd loses approximately 40 percent of its stored energy in three months, lead acid self-discharges the same amount in one year.

Lead acid batteries are inexpensive on cost-per-watt but are less suitable for repeated deep cycling. A full discharge causes strain and each discharge/charge cycle permanently robs the battery of a small amount of capacity. This loss is tiny while the battery is in good operating condition; however, the fading becomes more acute once the performance drops below 80 percent of its nominal capacity. This wear-down characteristic also applies to all batteries in various degrees.

Depending on the depth of discharge and operating temperature, lead acid for deep-cycle applications provides 200 to 300 discharge/charge cycles. The primary reasons for its relatively short cycle life are grid corrosion on the positive electrode, depletion of the active material and expansion of the positive plates. These changes are most prevalent at higher operating temperatures and are permanent.

The optimum operating temperature for a VRLA battery is 25°C (77°F). As a guideline, every 8°C (15°F) rise above this temperature cuts battery life in half. A lead acid that would last for 10 years at 25°C would only be good for five years if continuously operated at 33°C (95°F). The same battery would endure a little more than one year at a temperature of 42°C (107°F).

Lead acid batteries are rated at a 5-hour (0.2C) and 20-hour (0.05C) discharge, and the battery performs best when discharged slowly. The capacity readings are notably higher at a slow discharge than with a fast rate. Lead acid can, however, deliver high pulse currents of several C if done for only a few seconds. This makes the lead acid well suited as a starter battery, also known asstarter-light-ignition (SLI). The high lead content and the sulfuric acid make lead acid environmentally unfriendly. The following section looks at the different architectures and explains why one battery type does not fit all.

Starter and Deep-cycle Batteries

The starter battery is designed to crank an engine with a momentary high power burst; the deep-cycle battery, on the other hand, is built to provide continuous power for a wheelchair or golf car. From the outside both batteries look alike; however, there are fundamental differences in design. While the starter battery is made for high peak power and does not like deep cycling, the deep-cycle battery has a moderate power output but permits cycling. Let’s examine the architectural difference between these batteries further.

Starter batteries have a CCA rating imprinted in amperes. CCA refers to cold cranking amps, which represents the amount of current a battery can deliver at cold temperature. SAE J537 specifies 30 seconds of discharge at –18°C (0°F) at the rated CCA ampere without dropping below 7.2 volts. (SAE stands for Society of Automotive Engineers.)

Starter batteries have a very low internal resistance, and the manufacturer achieves this by adding extra plates for maximum surface area (Figure 1). The plates are thin and the lead is applied in a sponge-like form that has the appearance of fine foam. This method extends the surface area of the plates to achieve low resistance and maximum power. Plate thickness isless important here because the discharge is short and the battery is recharged while driving;the emphasis is on power rather than capacity.

Figure 1: Starter battery The starter battery has many thin plates in parallel to achieve low resistance with high surface area. The starter battery does not allow deep cycling. Courtesy of Cadex

Deep-cycle lead acid batteries for golf cars, scooters and wheelchairs are built for maximum capacity and high cycle count. The manufacturer achieves this by making the lead plates thick (Figure 2). Although the battery is designed for cycling, full discharges still induce stress, and the cycle count depends on the depth-of-discharge (DoD). Deep-cycle batteries are marked in Ah or minute of runtime.

Figure 2: Deep-cycle battery The deep-cycle battery has thick plates for improved cycling abilities. The deep-cycle battery generally allows about 300 cycles. Courtesy of Cadex

A starter battery cannot be swapped with a deep-cycle battery and vice versa. While an inventive senior may be tempted to install a starter battery instead of the more expensive deep-cycle on his wheelchair to save money, the starter battery won’t last because the thin sponge-like plates would quickly dissolve with repeated deep cycling. There are combination starter/deep-cycle batteries available for trucks, buses, public safety and military vehicles, but these units are big and heavy. As a simple guideline, the heavier the battery is, the more lead it contains, and the longer it will last. Table 3 compares the typical life of starter and deep-cycle batteries when deep-cycled.

Table 3: Cycle performance of starter and deep-cycle batteries. Starter batteries and deep-cycle batteries have their unique purposes and cannot be interchanged.

Absorbent Glass Mat (AGM)

AGM is an improved lead acid battery with higher performance than the regular flooded type. Instead of submerging the plates into liquid electrolyte, the electrolyte is absorbed in a mat of fine glass fibers. This makes the battery spill-proof, allowing shipment without hazardous material restrictions. The plates can be made flat like the standard flooded lead acid and placed in a rectangular case, or wound into a conventional cylindrical cell.

AGM has very low internal resistance, is capable of delivering high currents and offers long service even if occasionally deep-cycled. AGM has a lower weight and provides better electrical reliability than the flooded lead acid type. It also stands up well to high and low temperatures and has a low self-discharge. Other advantages over regular lead acid are a better specific power rating (high load current) and faster charge times (up to five times faster). The negatives are slightly lower specific energy and higher manufacturing costs.

AGM batteries are commonly built to size and are found in high-end vehicles to run power-hungry accessories such as heated seats, steering wheels, mirrors and windshields. Starter batteries also power navigation systems, traction and stability control, as well as premium stereos. NASCAR and other auto racing leagues choose AGM products because they are vibration resistant. Start-stop batteries are almost exclusively AGM. The classic flooded type is not robust enough and repeated micro cycling would induce capacity fade.

AGM is the preferred battery for upscale motorcycles. It reduces acid spilling in an accident, lowers weight for the same performance and allows installation at odd angles. Because of good performance at cold temperatures, AGM batteries are also used for marine, motor home and robotic applications.

As with all gelled and sealed units, AGM batteries are sensitive to overcharging. These batteries can be charged to 2.40V/cell (and higher) without problem; however, the float charge should be reduced to between 2.25 and 2.30V/cell (summer temperatures may require lower voltages). Automotive charging systems for flooded lead acid often have a fixed float voltage setting of 14.40V (2.40V/cell), and a direct replacement with a sealed unit could spell trouble by exposing the battery to undue overcharge on a long drive.

AGM and other gelled electrolyte batteries do not like heat and should be installed away from the engine compartment. Manufacturers recommend halting charge if the battery core reaches 49°C (120°F). While regular lead acid batteries need a topping charge every six months to prevent the buildup of sulfation, AGM batteries are less prone to this and can sit in storage for longer before a charge becomes necessary.

Ever since Cadillac introduced the electric starter motor in 1912, lead acid remained the natural choice of battery to crank the engine. Lead is toxic and environmentalists would like to replace it with another chemistry. Europe succeeded in keeping nickel-cadmium batteries out of consumer products, and authorities try to do the same with the starter battery. The choice is lithium-ion, but at a price tag of $3,000, it won’t fly. Regulators hope that advancements being made in the electric powertrain will lower the cost, but such a large price reduction to match lead acid may not be possible. Lead acid will continue to be the battery of choice to crank the engines.

In summary, Table 4 spells out the advantages and limitations of common lead acid batteries in use today. The table does not include the new chemistries discussed above or those under development.

Table 4: Advantages and limitations of lead acid batteries. Flooded and dry systems are similar.

A huge music catalog free and unlimited use through advertising , and has been promoted Spotify since hatching business model nearly three years, expanding to most European countries and trying, again and again, across the pond to the new continent.

But it has reached a turning point for the service of Swedish origin and we will experience it soon, especially if we make use of an account Open or Free , which are hitherto been free with ads. From now on, reach new limits designed to promote paid subscription to this program, and here’s the details:

What are these changes?

* Spotify entire catalog is still available to any user, but those who have accounts Free or Open can only hear up to 5 times each song . Once this limit, it turns off the catalog.

* The monthly limit listening time increases and now comes the Free Spotify users. In either of two free forms, users can only listen to 10 hours a month of music Spotify catalog.

Who is affected by these changes and from when?

These changes will be effective from May 1 to all users of Free or Open accounts registered before November 2, 2010 . In the event that your account is more recent than that date will have until November 1, 2011 , ie six months without such limitations.

Of course, the limits described above shall not apply to songs you’ve imported into Spotify from your hard drive .

And the reasons for Spotify?

The creators of the greatest musical phenomenon of the Internet in recent years argue that these measures are necessary to ensure that its business model to move forward . This strategy is a clear motivation for users who were hesitant about paying for this service, you decide to take the plunge, either in the form Unlimited , for euros 4.99, or premium , of 9.99 euros and Releases exclusive access to and use of the version for mobile Spotify .

As reassuring reason, Spotify says that the average user would only limit of 5 copies in 30% of the music you hear, ie not notice this change in 7 out of 10 songs .

These figures have not been proven, nor reassure users with a fixed collection of items that will have to continue listening to his songs by other means.

What I can do now to listen to music without limits?

Mainly you have two options:

1. Get a Spotify account payment will be abandoned to these limits and, incidentally, with the increasing amount of advertising the program. You can do it here .

2. Draw on their alternatives, as Grooveshark or Musicue , whose business models are supported also by advertising but not limited to, for now, the playing time of the catalog.

Espacio en blanco

What do you think these changes? Will they in the business of Spotify or, conversely, will generate more subscriptions and they will improve over time?