Batteries

These are not normally used as a main power source for audio or video equipment, but are often used in auxiliary devices, e.g. remote wireless or infrared controllers, microphones, etc. There are many different chemical systems employed in these cells, some using very expensive components (Sony Vaio VGN-FZ battery) .

The requirement for, say, a clock battery, which will be expected to supply a comparatively low amount of energy for a year or so, is different than that required for a battery powering a digital camera with a flash lamp, which has to supply pulses of relatively high power (Sony VGP-BPS8 battery) .

Within many electronic devices, for example real time clock circuitry and memory maintenance circuitry, there is a requirement for primary cells which will supply a low amount of power for ten or so years.

A few advantages of primary cells are that they are easily available, at least in the standard consumer sizes, have a long shelf life and a high power density (Sony VGP-BPL9 battery) .

As an emergency backup, then it can be useful to have a battery pack which will take standard primary cells, but chose an easily available cell size, AA, C or D

Originally, (well, in my childhood days) most primary cells were of zinc-carbon construction (Sony VGP-BPL11 battery) .

A later development was zinc chloride which has a greater capacity, whereas now most primary cells are of alkaline construction. However, in some situations the high capacity of the alkaline cells can cause a hazard due to sparking on installation. For example, a standard alkaline Duracell D cell has a capacity of 18000mAh, and therefore Zinc based cells are still used in hazardous situations (Sony VGP-BPL15 battery) .

Later cell technologies include zinc air, which provide energy only when a protective seal is removed and they thus have a very defined operational life. Other chemistries include silver oxide, mercury, and a whole range of lithium based cells, such as lithium iron sulphide, lithium manganese dioxide and lithium thionyl chloride (Sony VGN-FZ460E battery) .

These cells are usually highly matched to a particular application, and give a saving in size and weight (but not usually cost) when compared with an alkaline cell of the same capacity (Sony VGP-BPS11 battery) .

Secondary Batteries.

These are the batteries that most of this article will be concerned with, and is the area that causes most energy supply problems, since we not only take energy from the cell, but have to replace it also, so the problems will be at least doubled (SONY VAIO VGN-FZ4000 Battery) .

I will only consider four types of secondary cell; lead acid gel, Nickel Cadmium (Ni-Cad or Ni-Cd), Nickel-Metal Hydride (Ni-MH), and lithium-ion (Li-ion) (Apple A1281 battery) .

Lead Acid Gel Batteries

These are my preferred batteries, for the following reasons: Easily recharged with constant current or constant voltage system. The same cell can be used for fast cycling or long term float applications. Low internal impedance allows very high discharge currents. Excellent mechanical and vibrational strength (Apple A1189 battery) .

Absolutely no 'memory' effects, so can be recharged at any state of discharge. No damage due to cell reversal. 2V per cell, meaning fewer cells for lower battery cost and higher reliability. Cells can be paralleled for additional capacity. Construction allows air transportation without restrictions, and they are allowed in every country （Apple A1148 battery) .

They have an easily monitored capacity, since they have a gently sloping discharge voltage/time curve. Their operational voltage range -65 deg C to +65 degC is excellent, and they are readily available in rectangular format in 6, 12 or 24V packs. They give a very reliable and predictable performance at a low cost (HP PAVILION DV9700t Battery) .

They also have a long charge cycle life - up to 2000 cycles or eight years on float charge. Always store them in a fully charged condition, and check every month or so and top up their charge. They will self discharge at about 3% per month (HP PAVILION DV2 Battery) .

You won't like them because they are heavy (see example below to see how wrong you are!!). You will also forget to check their charge condition if not using them for a period of time (Dell INSPIRON 1420 Battery) .

Let us look at the Yuasa NP7-12 battery in more detail. This 12V battery has a capacity of 7.0Ah - that is at a 20 hour rate of 350mA to 10.5V. At a one hour rate of 4200mA then it has a capacity of 4.2Ah to an end voltage of 9.6V. The maximum discharge current with the standard spade terminals is 40A, and it has a charge retention of 85% over 6 months (Dell Inspiron E1505 Battery) .

It is in a robust plastic case about 151mm by 65mm by 98mm high, although it may be used in any position. It weighs 2.65Kg. Retails at about £15.00. A suitable constant current mains charger is readily available for £20.00, but it is feasible to use an even cheaper wall block type device at 0.1C for overnight charging (Dell Latitude D620 Battery) .

Now, if we try and make up a similar capacity Ni-Cad pack, we need 10 cells, since each is 1.2V. We will require a case and we will also need to do some wiring to connect the cells in series. A suitable 7Ah Ni-Cad cell is 33mm diam x 91mm high, and weighs 230gms at a retail price of about £9.50 each (Dell INSPIRON 1525 Battery) .

If we mount them in a block, as two rows of five, then we end up with a pack 91mm high by 66mm wide by 165mm long. This will be larger than the lead acid battery with the same rating when we put a rigid case around it. The total weight will be at least 2.3Kg, since we must be add wiring and the weight of the case. A decent charger/discharger may well cost £100 or so, the assembled battery pack in a case is likely to cost £150.00 (Dell Inspiron 6400 battery) .

Nickel Cadmium Batteries

Bearing in mind my list of advantages for lead acid batteries, why use Ni-Cads? The lead based storage battery was invented in 1859 (about ten years before the first dry cell), and it was about 100 years later that the sealed gel type lead acid battery was perfected (Toshiba PA3535U-1BRS battery) .

The Nickel Cadmium storage cell was invented in 1899, and it was not until the early 1960's that the sealed Ni-Cad cell started to be used, although the first sealed unit was developed in 1947. Well, historically the sealed devices seemed to appear at about the same time (IBM ThinkPad R50 battery) ,

so we can not say that one is more popular than the other because of tradition, but lead acid batteries have existed for a long time in their liquid form, and they were, and still are used for heavy power requirements, and I believe that is why lead acid gel batteries are not more popular for AV users - it is not being marketed into the AV area (COMPAQ Presario R3000 Battery) .

Most Ni-Cad cells are available as size for size replacements for the common consumer and industrial sized primary cells, and the cell voltage at 1.2V and a pretty level 1.2V at that, is comparable with the 1.5V of most primary cells (ASUS Eee PC 1000HE Battery ) .

Lead acid, at 2V, just does not have this market, so they are not made in the smaller sizes, and if we were using four lead acid cells to replace four primary cells, then we would have a serious over voltage problem. That, I believe is the commercial reason, but what about the technical reason for Ni-Cad's popularity (ASUS Eee PC 900 Battery) .

The major advantage of Ni-Cads is that the discharge voltage is constant, until it reaches a knee point at the end of the discharge cycle, when it rapidly falls. For many electrical/electronic devices in the 1960's, then if you had a consistent 6V supply, say, from 5 Ni-Cad cells, then an amplifier would perform just as well after one hour's use as at the beginning (ACER Aspire 3020 Battery) .

Electronics were relatively expensive, and it was unnecessary to have voltage regulators if you used Ni-Cad batteries. With lead acid gel batteries, then the amplifier performance may not be as good after one hour, but it would never suddenly fail (Dell Inspiron 6000 battery) .

Where a constant voltage was required, then regulators were necessary if using lead acid batteries, adding more cost to the device. The early regulators were also not very efficient, the excess power being mainly dumped as heat (Toshiba PA3399U-2BAS Battery) .

One problem with Ni-Cads, is the so called 'memory effect'. Many manufacturers have improved their batteries and now better understand this phenomenon.

Discovery Battery Rapid Tests

When I asked a major manufacturer of batteries, "Is it feasible to rapid tests in batteries? " the engineer in a firm tone replied:" No. "His conclusion was based on the difficulty of using a universal testing method applicable to all battery applications, from wireless communications to mobile computing tools power forklifts and electric vehicles (Sony Vaio VGN-FZ battery).

Several universities and companies, including Cadex Electronics, are efforts to find a manageable solution for rapid verification of batteries. They have tried many methods, and some have failed to be inaccurate and impractical (Sony VGP-BPS8 battery).

By studying the characteristics associated with health status and state of charge (SoH and SoC respectively) of the batteries can observe some interesting effects. Unfortunately, these properties are irregular and nonlinear, and worst of all, the parameters are unique for each type of battery. This makes it difficult to create a formula that is applied in all batteries (Sony VGP-BPL9 battery).

Despite these seemingly insurmountable complexity, verification batteries can be quick. But the question one asks is, "What accuracy will have, and how to adapt to chemical compositions permanently changing the batteries (Sony VGP-BPL11 battery)?

The secret of quick checks battery lies in understanding how to use the same energy. The battery charges vary from short current peaks for a digital mobile phone (PCS, GSM), a significant charges intermittent power tools, and food for a constant current laptops.

The first step in obtaining readings quick check is to measure the battery internal resistance, often called impedance. Impedance measurements take only a few seconds and provide a fairly accurate indication of battery condition, especially if you have a baseline reading of a good battery for comparison (Sony VGP-BPL15 battery).

Unfortunately, the impedance measurement provides only a rough idea of battery performance. The readings are affected by different conditions of the battery can not always be controlled. For example, a fully charged battery just out of the charger shows a higher impedance than one that has remained motionless for a few hours after charging. The high impedance noise is due to electro-chemistry that exists after the load. Allowing the battery to rest one or two hours, the normalized (Sony VGN-FZ460E battery). Temperature also affects the readings. In addition, the chemical process, the number of cells connected in series and a battery capacity, influence the results. Many batteries also contain a protection circuit that distorts other readings (Sony VGP-BPS11 battery).

The lithium battery changing

In a recent conversation with a major manufacturer of batteries Lithium-ion, I learned that the chemical processes of change lithium batteries every six months. Will discover new chemical compositions that provide better load characteristics, higher capacity and longer storage life. Although beneficial for users, these improvements make havoc in the battery test equipment, which base their rapid test algorithms set parameters. Let me explain why these changes in the composition of the battery affect the test results with rapid testers (SONY VAIO VGN-FZ4000 Battery).

The first lithium-ion showed a gradual drop in voltage during discharge. With the newer lithium batteries, you can achieve a higher voltage level. These batteries provide a more stable voltage for most of the discharge cycle. The rapid drop in voltage occurs only at the end of the discharge (Sony VGP-BPS10 battery).

A pre-wired test looks for a voltage drop early and estimating SoH fixed according to the knowledge available for reference. If the drop voltage changes due to improved battery technology will result erroneous readings ( Sony VGP-BPS3 battery).

The different metals disturb the positive electrode voltage open terminal. Manganese has a terminal voltage slightly higher compared with the traditional cobalt. In addition, manganese ages differently to cobalt.Although both cobalt and manganese systems belong to the family of Li-ion, is likely to produce differences in the readings when testing a battery quick side by side (Sony VGP-BPS2 battery).

Lithium-polymer has a composition different from lithium-ion and responds differently when testing. The instruments capable of verifying Lithium-ion may not be reliable in its readings when used in rapid tests Lithium-polymer batteries (Sony Vaio VGN-FZ21M battery ).

Will the Fuel Cell have a Second Life?

The fuel cell enjoyed the height of popularity in the1990s when scientists and stock promoters envisioned a world run on clean and inexhaustible resource – hydrogen. They predicted cars running on fuel cells and households generating electricity from back-yard fuel cells. Improvements in stack design during that time led to increased power densities and lower costs. The stock prices skyrocketed and promoters got blinded. High manufacturing costs, marginal performance and short service life stood in the way of turning the hydrogen dream into reality. Hype and investment funding has since moderated and we hope that a more sensible approach will eventually find the proper use for the fuel cell (Sony Vaio VGN-FZ battery).

Before resetting expectations, it had been said that the fuel cell is as revolutionary in transforming the world as the microprocessor had been. Experts uttered further that using an inexhaustible source of fuel, hydrogen, would improve the quality of life, and environmental concerns of burning fossil fuels would be solved forever. From 1999 through 2001, over 2,000 organizations were actively involved in fuel cell development and four of the largest public fuel cell companies in North American raised more than a billion dollars in public stock offerings. What went wrong? Is burning hydrogen instead of fossil fuel a misconception? Let’s look at this closer (Sony VGP-BPS8 battery).

A fuel cell is twice as efficient to convert carbon fuel to electricity than combustion does. Hydrogen, the simplest element consisting of one proton and one electron, is plentiful and exceptionally clean as a fuel. Hydrogen makes up 90 percent of the universe and is the third most abundant element on the earth’s surface. Such a wealth of fuel would provide an almost unlimited pool of energy at relatively low cost, but there is a hitch(Sony VGP-BPL9 battery).

The fuel cell core (stack) that converts oxygen and hydrogen to electricity is expensive to build and hydrogen is more costly to produce than gasoline in terms of net calorific value (NCV). Some say that hydrogen is nearly energy neutral, meaning that it takes as much energy to produce as it delivers at the end destination. Unless the energy source used to produce hydrogen comes from a renewable source, hydrogen will not solve the energy issue, nor will it reduce the carbon footprint (Sony VGP-BPL11 battery) .

Hydrogen is not a source of energy per se but represents a medium to transport and store it. When envisioning “burning an endless supply of hydrogen,” we must first produce the resource. Hydrogen is not abundantly available in the earth ready to use, as oil and natural gas is and needs other energies to make it into a usable product, similar to electricity to charge a battery. If electricity produces hydrogen, then this energy source should come from a renewable resource. This is not always the case and much comes is derived from burning coal, oil and natural gas (Sony VGP-BPL15 battery).

Fossil fuel lends itself well to produce hydrogen, however, converting this valuable fuel to hydrogen does not make much sense when considering that the process does not add much value. Seen from this angle, hydrogen cannot compete with fossil fuel pumped “free” from the earth as a gift to humanity (Sony VGN-FZ460E battery).

Fuel storage is a further disadvantage. Liquid hydrogen has a low energy density and the volumetric storage in terms of energy is about five times less than petrol products. In liquid form, hydrogen needs extensive insulation for cold keeping, and in gaseous form pressurized hydrogen requires heavy storage tanks (Sony VGP-BPS11 battery).

A reformer would allow the use of methanol, propane, butane and natural gas, however, when converting these fossil fuels into pure hydrogen, some leftover carbon is being released. Although 90 percent less potent than what comes from the tailpipe of a car, carrying a reformer adds to vehicle weight and increases cost. In addition, reformers are known to be sluggish and the net benefit of the fuel cell over the internal combustion engine diminishes (SONY VAIO VGN-FZ4000 Battery).

Sir William Grove, a Welsh judge and gentleman scientist developed the fuel cell concept in 1839, but the invention never took off. This was in part due to the rapidly advancing internal combustion engine that promised better early results. It was not until the second half of the 20th century that the fuel cell was put to practical use during the Gemini space program in the 1960s. NASA preferred this clean power source to nuclear or solar energy and the alkaline fuel cell system that was chosen generated electricity and produced the drinking water for the astronauts (Sony VGP-BPS10 battery).

High material cost made the fuel cell prohibitive for commercial use at that time. This did not hinder Dr. Karl Kordesch, the co-inventor of the alkaline battery, from converting his car to an alkaline fuel cell in the early 1970s. Kordesch drove his car for many years in Ohio, USA. He placed the hydrogen tank on the roof and utilized the trunk for the fuel cell as well as back-up batteries. According to Kordesch, there was “enough room for four people and a dog.” (Sony Vaio VGN-FZ21M battery )

A fuel cell is an electrochemical device that combines hydrogen fuel with oxygen to produce electricity, heat and water. The fuel cell is similar to a battery in that an electrochemical reaction takes place as long as fuel is available. The hydrogen fuel is stored in a pressurized container and oxygen is taken from the air. Because of the absence of a burning process, there are no harmful emissions, and the only byproduct is fresh water. The water emitted from the proton exchange membrane fuel cell (PEMFC) is so pure that visitors of Vancouver’s Ballard Power Systems were being served hot tea made from this clean water (Apple A1281 battery).

Fundamentally, a fuel cell is electrolysis in reverse, using two electrodes separated by an electrolyte. The anode (negative electrode) gets the hydrogen and the cathode (positive electrode) the oxygen. A catalyst at the anode separates hydrogen into positively charged hydrogen ions and electrons, the oxygen is ionized and migrates across the electrolyte to the anodic compartment where it combines with hydrogen. A single fuel cell produces 0.6 to 0.8V under load. To obtain higher voltages, several cells are connected in series (Apple M9848LL/A battery).

Fuel Cell in a Vehicle

Fuel cells for automotive use the Proton Exchange Membrane, or PEM for short. PEM uses a polymer electrolyte and is one of the furthest developed and most commonly used fuel cell systems today. The PEM system allows compact design and achieves a high energy to weight ratio. Another advantage is the relatively quick start-up when applying hydrogen. The stack runs at a moderate temperature of about 80°C (176°F) and has a 50-percent efficiency(Apple A1189 battery).

The limitations of the PEM fuel cell are high manufacturing costs and complex water management systems. The stack contains hydrogen, oxygen and water and if dry, water must be added to get the system going; too much water causes flooding. The system requires pure hydrogen; lower fuel grades can cause decomposition of the membrane. Testing and repairing a stack is difficult and this becomes apparent when realizing that a 150V, 50kW stack to power a car requires 250 cells (Apple M8665G/A battery).

Extreme operating temperatures are a further challenge. Freezing water can damage the stack and the manufacturer recommends heating elements to prevent ice formation. When cold, the start-up is slow and at first the performance is poor. Excessive heat can also cause damage and controlling the operating temperatures, as well as supplying enough oxygen requires compressors, pumps and other accessories that consume about 30 percent of the energy generated (HP PAVILION DV2000 Battery).

If operated in a vehicle, the PEMFC stack has an estimated service life of 2000-4000 hours. Start and stop conditions, induce drying and wetting, contribute to membrane stress. Running continuously, the stationary stack is good for about 40,000 hours. Stack replacement is a major expense (HP PAVILION DV3000 Battery).

Although the fuel cell assumes the duty of the IC engine in a vehicle, poor response time and a weak power band make onboard batteries necessary. In this respect, the FC car resembles an electric vehicle with an onboard power aggregate to keep the batteries charged. The battery is the master and the fuel cell becomes the slave. On start-up, the vehicle relies 100 percent on the battery and the fuel cell only begins contributing after reaching the steady state in 5-30 seconds. During the warm-up period, the battery must also deliver power to activate the air compressor and pumps. When warm, the FC provides enough power for cruising, and when accelerating or climbing hills both FC and battery provide power. During breaking, the kinetic energy is being returned to charge the battery (Dell INSPIRON 1420 Battery).

The FC of a mid-sized car generates around 85kW, or 114hp, and the power couples to an electric motor of similar capacity. The onboard battery has a capacity of around 18kW and provide throttle response and power assist when passing vehicles or climbing hills. The battery serves a buffer similar to the HEV and does not get stressed by repeated deep cycling and fast charging, as is the case with the EV (Dell Inspiron E1505 Battery).

Hydrogen costs about twice as much as gasoline but the high efficiency of the FC compared to the IC engine in converting fuel to energy gives the same net effect on the pocket book except less greenhouse gases and reduced pollution (Dell Latitude D620 Battery).

Hydrogen is commonly derived from natural gas and we ask why not burning natural gas directly in the IC engine instead of converting it to hydrogen through a reformer and then transforming it to electricity in a fuel cell to feed the electric motors? The answer is efficiency. Burning natural gas in a combustion turbine to produce electricity has an efficiency factor of only 26-32 percent, while using a FC is 35-50 percent efficient. We must keep in mind that the machinery required with the clean FC is far more expensive and requires added maintenance than simply using a burning process (Dell INSPIRON 1525 Battery).

We have no hydrogen infrastructure and building it is prohibitive. Refueling stations reforming natural gas to hydrogen to support 2,300 vehicles cost over $2 million to build. In comparison, a charging outlet for the EV is less the $1000, but the refill time would be longer than with the FC. Meanwhile, we have plenty of gas stations that offer a quick fill-up of cheap fuel (Dell Inspiron 6000 battery).

Durability and cost are other concerns with the fuel cell and here we have seen some encouraging improvements. The service life of a FC in car driven in normal traffic conditions has doubled from 1,000 hours to 2,000 hours. The target for 2015 is 5,000 hours, or the full life of a vehicle driving 240,000 km (150,000 miles). Another challenge is cost. The fuel cell costs substantially more than an IC engine and until mass-produced, pricing for a cost comparisons is impractical to make. As a simple guideline, the FC vehicles will be more expensive than plug-in hybrids, and the plug-in hybrid cost more than a regular gasoline powered car (Dell Inspiron 6400 battery).

It is conceivable that the fuel cell will never become the engine of choice that experts had hoped and there could be similarities with the failed attempt to fly airplanes on a steam engine in the mid 1800s. It is, however, everyone’s desire that the fuel cell will succeed, and taxpayers may one day have to pay to open the markets similar to subsidizing the electric car. It is also conceivable that governments might in the future mandate the use of fuel cells for environmental reasons. Fuel cells could also become the energy source of choice once the supply of fossil fuel gets dangerously low. Meanwhile, we hope that the development of the fuel cell will continue and become a replacement for the polluting internal combustion engine (Toshiba PA3535U-1BRS battery).

Is the Electric Car Mature?

Cars with electric drive trains have been around for more than 100 years. At the turn of the century in 1900, a car buyer had three choices of propulsion systems: electric, steam and internal combustion engine, of which the IC engine was the least common (Sony Vaio VGN-FZ battery).

The electric cars appealed to the upper class and the vehicles were finished with fancy interiors and expensive materials. Although higher in price than the steam and gasoline-powered vehicles, the wealthy chose the electric car for their quiet and comfortable ride over the vibration, smell and high maintenance of the gasoline-powered counterpart. Best of all, EV (electric vehicles) did not require changing gears, the most dreaded part in driving a gasoline car then. Nor did the EV need manual cranking to start the motor, a task the upper class did not want to be seen doing. Since the only good roads were in town, the limited range of the EV was no problem and most of the driving was local commuting. The production of the EV peaked in 1912 and continued until the 1920s (Sony VGP-BPS8 battery).

The battery choice was lead acid, and for an up-price the buyer could fit the Detroit Electric with nickel-iron (NiFe), a battery Thomas Edison promoted. NiFe has a cell voltage of 1.2V, was robust and durable even when over-charged and fully discharged. Being a good businessman, Edison advocated NiFe over lead acid but the popularity for this battery began to decline after a fire destroyed the Edison factory and laboratory in 1914. NiFe provided only a slightly better energy density to lead acid and was expensive to manufacture. In addition, the battery performed poorly at low temperature and the self-discharge was 20-40 percent a month, considerably higher than lead acid (Sony VGP-BPL9 battery).

Detroit Electric, one of the most popular EVs then, were said to get 130km (80 miles) between battery charges. Its top speed was 32km (20 miles) per hour, a pace considered adequate for driving. Physicians and women were the main buyers. Thomas Edison, John D. Rockefeller, Jr. and Clara Ford, the wife of Henry Ford, drove Detroit Electrics. Figure 1 shows Thomas Edison with his 1914 Detroit Electric model.

Batteries play an important role in electric powertrains and the price per kilo-watt-hour varies according to battery type. Table 1 lists typical batteries for mobility, and at $160 per kWh the starter battery is most economical, followed by the forklift battery. Newer technologies are more expensive and this is due to costly raw materials, complex manufacturing procedures, and electronic safety and management systems. Higher volume production will only moderate the price marginally (Sony VGP-BPS9 battery).

Cost cutting as part of mass-production by Henry Ford and the invention of the starter motor in 1912 moved the preference of car buyers to gasoline-powered vehicles. By the 1920s, intercity roads required long-range vehicles and the discovery of Texas crude oil made gasoline affordable to the general public. The EV became a thing of the past until the early 1990s when the California Air Resources Board (CARB) began pushing for more fuel-efficient and lower emission vehicles and mandated the zero-emission car (Sony VGP-BPL11 battery).

It was the CARB zero-emission policy that prompted General Motors to produce the EV1. Available for lease between 1996-1999, this early electric vehicle run on a 18kWh lead acid battery that was later replaced with a 26kWh NiMH pack. Although the NiMH battery gave an impressive driving range of 260 km (160 miles), the EV1 was not without problems. Manufacturing rose to three times the cost of a regular gasoline-powered car and in 2001 politicians changed the CARB requirements, which prompted General Motors to withdraw the EV1 to the dismay of many owners. The 2006 documentary film “Who Killed the Electric Car?” gives a mixed impression of government-induced programs for cleaner transportation (Sony VGP-BPL15 battery).

To match the convenience of an IC powered vehicle, the EV needs a battery capable of delivering 25-40kWh. This is twice the battery size of a PHEV and ten-times that of the HEV. The electrochemical battery is not the only added expense; the power electronics to manage the battery make up a large part of the vehicle cost. An EV without a battery is roughly the same cost as a traditional gasoline-powered car (Sony VGN-FZ460E battery).

It will take a day to fully charge the electric Mini on a regular 115AC outlet. High-power outlets can reduce the charge time to 3-5 hours, and public fill-up stations can charge a battery in two hours. The electrical outlet, not the battery, governs charge times. Charging a 40kWh battery in six minutes, as some battery manufacturers might claim, would require 400kW of power. An ordinary 115VAC electrical outlet provides only 1.5kW and a 230VAC, 40A kitchen stove outlet delivers 9kW (Sony VGP-BPS11 battery).

Car manufacturer Tesla Motors focuses on building EVs that generate zero-emissions with very high performance. The Silicon Valley roadster boasts a zero to 96km (zero to 60 miles) acceleration time of 3.9 seconds. The 7000 Li-ion cells store 53kWh of electrical power and promise a driving range of 320km (200 miles). Liquid cooling prevents the pack from exceeding 35°C (95°F). To achieve a five-year warranty, Tesla charges the Li-ion cobalt cells to only 4.10V instead of 4.20V/cell, and electronics circuits inhibit charging in freezing temperatures. At $130,000, this car turns heads and becomes a discussion item, however, the $40,000 of a replacement battery could causes concern for long-term owners (SONY VAIO VGN-FZ4000 Battery).

Batteries for the electric powertrain currently cost between $1,000-1,200 per kWh. According to The Boston Consulting Group (BCG), relief is in sight. They claim that within the next decade the price of Li-ion will fall to $750 per kWh. Meanwhile, batteries for consumer electronics are only around US$250-400 per kWh. High volume, automated manufacturing, lower investments in safety and shorter calendar life makes this low price possible. BCG predicts that Li-ion batteries for the powertrain will eventually match these consumer prices, and the cost of a 15kWh battery will drop from $16,000 to about $6,000. The largest decrease in battery prices is expected to occur between now and 2020, with a more gradual decline thereafter. According to BCG, the anticipated calendar life of the battery will be 10-15 years (Sony VGP-BPS10 battery).

E-One Moli Energy, a manufacturer of lithium-ion cells for power tools and electric vehicles, says that the cost of Li-ion can be reduced to $400 per kWh in high volume but the peripheral electronics managing the battery will remain high and this added cost is know to double the price of a pack. Reductions are also possible here and E-One Moli Energy predicts that the electronics will only make up only 20 percent of the battery cost in five years. These forecasts are speculative and other analysts express concern that the carmakers may not be able to achieve the long-term cost target without a major breakthrough in battery technology. They say that the current battery cost is 3-5 times too high to appeal the consumer market ( Sony VGP-BPS3 battery).

Driving on electricity is cheaper and cleaner than burning gasoline, but at today’s low fuel prices, uncertainty regarding the service life of the battery, along with unknown abuse tolerances and high replacement costs will lower the incentive for buyers to switch from a proven concept to an electric vehicle. Technology Roadmaps Electric and plug-in hybrid electric vehicles (EV/PHEV) says that if a driver wants a 500 km range between fill-ups achievable with an IC powered car, the battery would need a capacity of 75 kWh. At an estimated $400 price tag per kWh, such a battery would cost over $30,000 and weigh nearly a ton. Figure 3 illustrates typical battery sizes used in cars with different powertrains (Sony VGP-BPS2 battery).

Roadmap compares the energy consumption and cost of gasoline versus electric propulsion as follows: The EV requires 150-200Wh per km, and at a consumption rate of 200Wh/km, and an electricity price of $0.15 per kWh, the fuel cost to drive an EV translates to $0.03 per km. We compare this figure with $0.06 per km for an equal-size gasoline-powered car and $0.05 per km for diesel. This price does excludes equipment costs, service and eventual replacement of the battery and engine (Apple A1281 battery).

The EV market attracts innovative companies to develop a better battery and many are taking advantage of generous government incentives offered, but there is a danger. For the sake of optimal energy density, some start-up companies are experimenting with aggressive design concepts using volatile chemicals that compromise safety. They push the envelope by announcing impressive advancements, emphasize only the pros and squelch the cons. Such behavior will get media attention and entice venture capitalists to invest, but hype does little in finding a lasting solution to improve existing battery technologies (Apple M9848LL/A battery).

The battery will determine the success of the EV and until major improvements have been achieved in terms of higher energy density, longer service life and lower cost, the electric powertrain will be limited to a small niche market. While governments are giving large contributions in the hope to improve current battery technologies, we must realize that the electrochemical battery has limitations. This was made evident when motorists tested eight current and future models with electric powertrains and attained driving ranges that were one third less than estimated. Table 4 lists a rundown. The vehicles were tested in real life conditions on highways, over mountain passes and under winter conditions. The information was collected at time of writing (Apple A1189 battery).

The environmental benefit of driving an EV will be minimal unless renewable resources provide the electricity to charge the batteries. Burning coal and fossil fuel to generate electricity simply shifts the pollution out of congested cities to the countryside. In the USA, electricity comes from burning 50 percent coal, 20 percent natural gas, 20 percent nuclear, 8 percent hydro and 2 percent solar and wind. One of the advantages of the EV is charging at night when the power grid has extra capacity (Apple M8665G/A battery).

Going electric may create another dilemma, which begs the question, “In the absence of fuel tax, who will pay for the maintenance and new construction of highways?” Roads cost governments billions to build and repair, and EV drivers will be entitled to use them for free, a gift that needs to be compensated with higher taxes. This poses an unfair burden for those taking public transportation as they pay double: tax for highways and the fair for bus or train. Raising road tolls may be an alternative (Apple M9677*/A battery).

The high cost of the EV against the lure of cheap and readily available fossil fuel will make the transition to a cleaner way of living more difficult. Government subsidies may be needed to make “green” cars affordable to the masses. Many argue that this handout of public money is unfair and suggest that the tax dollars should go to building more efficient public transportation systems （Apple A1148 battery）.

The goal of governments should be to remove cars from the roads by offering other modes of transportation. Commuter trains are one of the most efficient alternatives in moving people comfortably and fast. Changing the focus away from cars would, for the first time in 100 years, hand our cities back to the people who are the rightful owners. Such a change in direction would make cities more enjoyable and future generations would thank their forefathers for prudent planning. It’s interesting to note that some of the nicest cities were built before the invention of the car. During this time, designers had the movement of people in mind and this was done out of necessity rather than foresight. Most of these desirable cities are in Europe, and North America appears to be trailing behind (Apple 661-2183 battery).

-font-family: "Times New Roman"'>Apple A1281 battery).

The EV market attracts innovative companies to develop a better battery and many are taking advantage of generous government incentives offered, but there is a danger. For the sake of optimal energy density, some start-up companies are experimenting with aggressive design concepts using volatile chemicals that compromise safety. They push the envelope by announcing impressive advancements, emphasize only the pros and squelch the cons. Such behavior will get media attention and entice venture capitalists to invest, but hype does little in finding a lasting solution to improve existing battery technologies (Apple M9848LL/A battery).

The battery will determine the success of the EV and until major improvements have been achieved in terms of higher energy density, longer service life and lower cost, the electric powertrain will be limited to a small niche market. While governments are giving large contributions in the hope to improve current battery technologies, we must realize that the electrochemical battery has limitations. This was made evident when motorists tested eight current and future models with electric powertrains and attained driving ranges that were one third less than estimated. Table 4 lists a rundown. The vehicles were tested in real life conditions on highways, over mountain passes and under winter conditions. The information was collected at time of writing (Apple A1189 battery).

The environmental benefit of driving an EV will be minimal unless renewable resources provide the electricity to charge the batteries. Burning coal and fossil fuel to generate electricity simply shifts the pollution out of congested cities to the countryside. In the USA, electricity comes from burning 50 percent coal, 20 percent natural gas, 20 percent nuclear, 8 percent hydro and 2 percent solar and wind. One of the advantages of the EV is charging at night when the power grid has extra capacity (Apple M8665G/A battery).

Going electric may create another dilemma, which begs the question, “In the absence of fuel tax, who will pay for the maintenance and new construction of highways?” Roads cost governments billions to build and repair, and EV drivers will be entitled to use them for free, a gift that needs to be compensated with higher taxes. This poses an unfair burden for those taking public transportation as they pay double: tax for highways and the fair for bus or train. Raising road tolls may be an alternative (Apple M9677*/A battery).

Can the Lead Acid battery compete in modern times?

During the mid 1970s, the maintenance-free lead acid battery was developed that could operate in any position. The liquid electrolyte was transformed into moistened separators and the enclosure was sealed. Safety valves were added to allow venting of gas during charge and discharge (Sony Vaio VGN-FZ battery).

Two designations of sealed lead acid batteries have emerged: the sealed lead acid (SLA), also known as Gelcell, which serves predominantly in wheeled mobility, and the large valve regulated lead acid (VRLA), which is used for stationary applications. This article focuses on the SLA (Sony VGP-BPS8 battery).

The SLA is not subject to memory. Leaving the battery on float charge for a prolonged time does not cause damage. The battery’s charge retention is best among rechargeable batteries. Whereas the NiCd self-discharges 40 percent of its stored energy in three months, the SLA self-discharges the same amount in one year. The SLA is relatively inexpensive to purchase but the operational costs can be more expensive than the NiCd if full cycles are required on a repetitive basis (Sony VGP-BPL9 battery).

The SLA does not lend itself to fast charging — typical charge times are 8 to 16 hours. The SLA must always be stored in a charged state. Leaving the battery in a discharged condition causes sulfation, a condition that makes the battery difficult, if not impossible, to recharge (Sony VGP-BPS9battery).

Unlike the NiCd, the SLA does not like deep cycling. A full discharge causes extra strain and each discharge/charge cycle robs the battery of a small amount of capacity. This wear-down also applies to other battery chemistries in varying degrees. To prevent the battery from being stressed through repetitive deep discharge, a larger SLA battery is recommended (Sony VGP-BPL11 battery).

The SLA provides 200 to 300 discharge/charge cycles. The primary reason for its relatively short cycle life is grid corrosion of the positive electrode, depletion of the active material and expansion of the positive plates. These changes are most prevalent at higher operating temperatures. Applying charge/discharge cycles does not prevent or reverse the trend (Sony VGP-BPL15 battery).

Among modern rechargeable batteries, the lead acid battery family has the lowest energy density, making it unsuitable for handheld devices that demand compact size. In addition, performance at low temperatures is poor. The high lead content makes the SLA environmentally unfriendly if carelessly disposed (Sony VGN-FZ460E battery).

Charging the Lead Acid battery

The charge algorithm for lead acid batteries differs from nickel-based chemistry in that voltage limiting rather than current limiting is used. The charge time of a SLA is 12 to 16 hours. With higher charge currents and multi-stage charge methods, the charge time can be reduced to 10 hours or less. SLAs cannot be charged as quickly as nickel or lithium-based systems (Sony VGP-BPS11 battery).

A multi-stage charger applies constant-current charge, topping charge and float charge (see Figure 1). During the constant current charge, the battery charges to 70 percent in about five hours; the remaining 30 percent is completed by the slow topping charge. The topping charge lasts another five hours and is essential for the well-being of the battery. If never completely saturated, the SLA would eventually lose its ability to accept a full charge and the performance of the battery is reduced. The third stage is the float charge, which compensates for the self-discharge after the battery has been fully charged (SONY VAIO VGN-FZ4000 Battery).

The charge voltage limit indicated in Figure 2 represents a temporary voltage peak when applying a full charge cycle. The battery cannot dwell on that level. Once fully charged and at operational readiness, the float charge maintains the voltage at a lower level. The recommended float charge voltage of most low-pressure lead acid batteries is between 2.25 to 2.30V/cell (Sony VGP-BPS10 battery).

The optimal float charge voltage shifts with temperature. A higher temperature demands slightly lower voltages and a lower temperature demands higher voltages. Chargers that are exposed to large temperature fluctuations are equipped with temperature sensors to optimize the float voltage ( Sony VGP-BPS3 battery).

Whereas the voltage settings in Figure 2 apply to low-pressure SLA with a pressure relief valve setting of about 34 kPa (5 psi), the cylindrical SLA by Hawker requires higher voltage settings. The voltage limits should be set according to the manufacturer’s specifications. Failing to apply the recommended settings causes a gradual decrease in capacity due to sulfation. Typically, the Hawker cell has a pressure relief setting of 345 kPa (50 psi). This allows some recombination of the gases during charge (Sony VGP-BPS2 battery).

The price of the Hawker cell is slightly higher than that of the plastic equivalent, but lower than the NiCd. Also known as the ‘Cyclone’, this cell is wound similar to a cylindrical NiCd. This construction improves the cell’s stability and provides higher discharge currents when compared to the flat plate SLA. Because of its relatively low self-discharge, Hawker cells are suited for defibrillators used on standby mode.

An SLA must be stored in a charged state. A topping charge should be applied every six months to avoid the voltage from dropping below 2.10V/cell. The topping charge requirements may differ with cell manufacturers (Apple A1281 battery).

An approximate charge-level indication can be obtained by measuring the open cell voltage while in storage. A voltage of 2.11V, if measured at room temperature, reveals that the cell has a charge of 50 percent and higher. If the voltage is at or above this threshold, the battery is in good condition and only needs a full charge cycle prior to use. If the voltage drops below 2.10V, several discharge/charge cycles may be required to bring the battery to full performance. When measuring the terminal voltages, the storage temperature should be observed. A cool battery raises the voltage slightly and a warm one lowers it (Apple M9848LL/A battery).

Some buyers who inspect the battery during quality control reject SLA batteries arriving from vendors with less than 2.10V per cell. Low voltage suggests that the battery may have a soft short, a defect that cannot be corrected with cycling. Although cycling may increase the capacity of these batteries, the extra cycles compromise the service life of the battery. Furthermore, the time and equipment required to make the battery fully functional adds to operational costs (Apple A1189 battery).

How to restore and prolong Sealed Lead Acid batteries

The SLA is designed with a low over-voltage potential to prohibit the battery from reaching its gas-generating potential during charge. Excess charging would cause gassing and water depletion. Consequently, the SLA can never be charged to its full potential (Apple M8665G/A battery).

Finding the ideal charge voltage limit for a sealed lead acid system is critical. Any voltage level is a compromise. A high voltage limit produces good battery performance, but shortens the service life due to grid corrosion on the positive plate. The corrosion is permanent and cannot be reversed. A low voltage preserves the electrolyte and allows charging under a wide temperature range, but is subject to sulfation on the negative plate (Apple M9677*/A battery).

Once the SLA battery has lost capacity due to sulfation regaining its performance is often difficult and time consuming. Reasonably good results in regaining lost capacity are achieved by applying a charge on top of a charge. This is done by fully charging an SLA battery, then removing it for a 24 to 48 hour rest period and applying a charge again. This is repeated several times, and then the capacity of the battery is checked with a full discharge. The SLA is able to accept some overcharge, however, too long an overcharge could harm the battery due to corrosion and loss of electrolyte （Apple A1148 battery）.

Applying an over-voltage charge of up to 2.50V/cell for one to two hours can reverse the effect of sulfation of the plastic SLA. During that time, the battery must be kept cool and careful observation is necessary. Extreme caution is required not to raise the cell pressure to venting point. Cell venting causes the membrane on some SLA to rupture permanently. Not only do the escaping gases deplete the electrolyte, they are also highly flammable (Apple 661-2183 battery)!

The Hawker cell can be stored at voltages as low as 1.81V. Reactivation is relatively easily. However, when activating, the cell voltage under charge may initially raise up to 5V while absorbing only a small amount of current. Within about two hours, the small charging current converts the large sulfate crystals back into active material. The internal cell resistance decreases and the charge voltage eventually returns to normal. At a voltage between 2.10V and 2.40V, the cell is able to accept a normal charge (Apple M9419ZH/A battery).

To prevent damage, current limiting must be applied to protect the battery. Always set the current limit to the lowest practical setting. If current limiting is not available, the battery should be observed at all times. Not all Hawker cells allow restoration after prolonged low voltage storage (Apple M9007LL/A battery).

Improving the capacity of an older SLA by cycling is mostly unsuccessful. Such a battery may simply be worn out. Cycling would just wear down the battery further. Unlike nickel-based batteries, the lead acid battery is not affected by memory.

SLA batteries are commonly rated at a 20-hour discharge. Even at such a slow rate, a capacity of 100 percent is difficult to obtain. For practical reasons, most battery analyzers use a 5-hour discharge when servicing SLA batteries. This typically produces 80 to 90 percent of the rated capacity. SLA batteries are normally overrated and manufacturers are aware of this (Apple M9008J/A battery) .

Summary

The SLA serves a market in which newer battery chemistries would either be too expensive and the upkeep too demanding. A modern replacement may simply be too delicate and fail prematurely due to harsh environment. For applications such as wheelchairs, scooters and small UPS units, the SLA has not found a suitable replacement that is both rugged and cost effective. But like any other battery, the SLA exhibits weaknesses and has needs that must be met to obtain a long and reliable service (Toshiba PA3535U-1BRS battery).

Getting the most of your batteries

A common difficulty with portable equipment is the gradual decline in battery performance after the first year of service. Although fully charged, the battery eventually regresses to a point where the available energy is less than half of its original capacity (Sony Vaio VGN-FZ battery).

Rechargeable batteries are known to cause more concern, grief and frustration than any other component of a portable device. Given its relatively short life span, the battery is also one of the most expensive and least reliable parts. In many ways, a battery exhibits human-like characteristics: it needs good nutrition, prefers moderate room temperature and with the nickel-based system, requires regular exercise to prevent the phenomenon called 'memory' (Sony VGP-BPS8 battery).

How to restore and prolong nickel-based batteries

When nickel-based batteries are mentioned, the word 'memory' comes to mind. Memory was originally derived from 'cyclic memory', meaning that a Nickel-cadmium (NiCd) battery could remember how much energy was required and would provide similar amounts on subsequent discharges. Improvements in battery technology have virtually eliminated this phenomenon. The modern term of 'memory' is a crystalline formation that robs the battery of its capacity. Applying one or several full discharge cycles can commonly reverse this effect (Sony VGP-BPL9 battery).

The active cadmium material of a NiCd battery is present in finely divided crystals. In a good cell, these crystals remain small, obtaining maximum surface area. Memory causes the crystals to grow, reducing the surface area. In advanced stages, the sharp edges of the crystals may penetrate the separator, initiating high self-discharge or an electrical short.

The effect of crystalline formation is most visible if a NiCd battery is left in the charger for days, or if repeatedly recharged without a periodic full discharge. Since most applications do not use up all energy before recharge, a periodic discharge to 1V/cell (known as exercise) is essential to prevent memory (Sony VGP-BPS9battery).

All NiCd batteries in regular use and on standby mode (sitting in a charger for operational readiness) should be exercised once per month. Between these monthly exercise cycles, no further service is needed and the battery can be used with any desired user pattern without memory concern (Sony VGP-BPL11 battery).

If no exercise is applied to a NiCd for three months or more, the crystals ingrain themselves, making them more difficult to break up. In such a case, exercise may no longer be effective in restoring a battery and reconditioning is required. Recondition is a secondary discharge that slowly removes the remaining battery energy by draining the cells to virtually zero volts. NiCd batteries can tolerate a small amount of cell reversal. During deep discharge, caution must be applied to stay within the allowable current limit to minimize cell reversal (Sony VGP-BPL15 battery).

How to prolong lithium-based batteries

Battery research is focusing heavily on lithium chemistries, so much so that one could presume that all future batteries will be lithium systems. In many ways, the Lithium-ion (Li-ion) is superior to nickel and lead-based chemistries (Sony VGN-FZ460E battery).

A Li-ion battery provides 300 to 500 discharge/charge cycles or two to three years of service from the time of manufacturing. The loss of battery capacity occurs gradually and often without the knowledge of the user. There are no remedies to restore Li-ion batteries when worn out.

Li-ion prefers a partial rather than a full discharge. Avoid depleting the battery fully too frequently. Instead, charge more often or use a larger battery. There is no memory to worry about (Sony VGP-BPS11 battery).

Although lithium-ion is memory-free in terms of performance deterioration, engineers often refer to "digital memory" on batteries with fuel gauges. Repeat small discharges with subsequent charges do not allow the calibration needed to track the chemical battery with the fuel gauge. A deliberate full discharge with recharge every 30 charges, or so, will correct this problem. Letting the battery run down in the equipment to the cut-off point will do this. If not done, the fuel gauge becomes increasingly less accurate (SONY VAIO VGN-FZ4000 Battery).

The aspect of aging is an issue that is often ignored. A time clock starts ticking as soon as the battery leaves the factory. The electrolyte slowly 'eats up' the positive plate, causing the internal resistance to increase. Eventually, the cell resistance reaches a point where the battery can no longer deliver energy, although the battery may still contain charge (Sony VGP-BPS10 battery).

How to restore and prolong lead acid batteries

The sealed lead acid battery, known as valve regulated lead acid (VRLA), is designed with a low over-voltage potential. This is done to prevent water depletion. Consequently, these systems never get fully charged and some sulfation will develop over time.

Finding the ideal charge voltage limit is critical. Any voltage level is a compromise. A high voltage limit produces good battery performance but shortens the service life due to grid corrosion on the positive plate. The corrosion is permanent. A low voltage protects the battery and allows charging under a higher temperature but is subject to sulfation on the negative plate ( Sony VGP-BPS3 battery).

Restoring a sulfated battery is difficult and time consuming. One method that provides reasonably good results is applying a charge on top of a charge. This is done by fully charging a battery, then removing it for a 24 to 48 hour rest period and applying a charge again. This process is repeated several times and the capacity is checked again with a full discharge. The lead acid battery is able to accept some overcharge but too much causes corrosion and loss of electrolyte (Sony VGP-BPS2 battery).

Applying an over-voltage charge of up to 2.50V/cell for one to two hours can also reverse sulfation. During treatment, the battery must be kept cool and careful observation is needed. Prevent venting. Most plastic VRLA batteries vent at 34 kPa (5 psi). Not only do escaping gases deplete the electrolyte, they are highly flammable (Apple A1281 battery).

Sealed lead acid batteries are also available in cylindrical form. The Cyclon by Hawker resembles an oversized D sized cell. If sulfated, applying an elevated charge voltage commonly reactivates the cell. Initially, the cell voltage may rise to 5V, absorbing only a small amount of current. In about two hours, the small charging current converts the large sulfate crystals back into active material. The internal cell resistance decreases and the charge voltage normalizes. When within 2.10V to 2.40V, the cell starts to accept normal charge. If the sulfation is advanced, this remedy does not work and the cell needs replacing (Apple M9848LL/A battery).

When applying over-voltage, current limiting must be applied. Always set the limit to the lowest practical setting on the power supply and observe the battery voltage and temperature during charge. Improving the capacity of an older lead acid battery by cycling is mostly in vain. Such a battery may simply be worn out and cycling wears it further down. The lead acid battery is not affected by memory (Apple A1189 battery).

VRLA batteries are commonly rated at a 20-hour discharge. Even at such a slow rate, a capacity of 100 percent is difficult to obtain. For practical reasons, most battery analyzers use a 5-hour discharge when servicing these batteries. This typically produces 80 to 90% of the rated capacity. VRLA cells are normally overrated and manufacturers are aware of this practice (Apple M8665G/A battery).

Battery Recovery Rate

Restoring batteries by applying controlled discharge/charge cycles varies with chemistry type, cycle count, maintenance practices and age of the battery. The best results are achieved with NiCd. Typically 50 to 70 percent of discarded NiCd batteries can be restored when using the exercise and recondition methods of a Cadex battery analyzer or equivalent (Apple M9677*/A battery).

Not all batteries respond well to exercise and recondition. An older battery may show low and inconsistent capacity readings. Another battery may get worse with each advancing cycle. An analogy can be made to a frail old man for whom exercise is harmful. Such a condition suggests battery replacement （Apple A1148 battery）.

Some older NiCd batteries recover to near original capacity when serviced. Caution should be applied when rehiring these old-timers because of possible high self-discharge. If in doubt, measure the self-discharge. A 10 percent self-discharge in the first 24 hours after charging is normal. Discard the battery if the self-discharge approaches 30 percent.

The recovery rate of NiMH is about 40 percent. The lower yield is in part due the reduced cycle life. Some batteries may exhibit irreversible heat damage suffered by incorrect charging. Elevated operating and storage temperatures also contribute to permanent capacity loss (Apple 661-2183 battery).

Lithium-based batteries have a defined age limit. Once the anticipated cycles have been delivered, no method exists to restore them. The main reason for failure is high internal resistance caused by oxidation. Operating the battery at elevated temperatures will momentarily improve the performance. However, the high internal resistance will revert to its former state when the temperature normalizes (Apple M9419ZH/A battery)

Many Li-ion batteries for cell phones are being discarded under the warranty return policy. Dealers have confirmed that 80 to 90 percent of these batteries can be repaired with a battery analyzer. Because no equipment is on hand, the batteries are often sent back to the manufacturers or are discarded without attempting to restore them.

Some Li-ion batteries fall asleep if discharged below 2.5V/cell. The internal safety circuit opens and the charger can no longer service the battery. Advanced battery analyzers feature a boost function to activate the protection circuit enabling a recharge. If the cell voltage has fallen below 1.5V/cell and has remained in that state for a few days, a recharge should be avoided because of safety concerns (Apple M9007LL/A battery).

The recovery rate for lead acid batteries is a low 15 percent. The reasons for the low yield may be due to incorrect charging methods, high cycle count, operating at elevated temperatures and old age (Apple M9008J/A battery) .

The question is often asked whether a restored battery will work as well as a new one. The breakdown of the crystalline formation on NiCd can be considered a full restoration. However, the battery will revert back to its former state if the required maintenance is denied. If the separator is damaged by excess heat or is marred by uncontrolled crystalline formation, that part of the battery will not improve (HP PAVILION DV9700t Battery).

Battery analyzers have become an important tool to test, exercise and restore batteries. The Cadex 7400, for example, accommodates NiCd, NiMH, Li-ion/polymer and lead acid batteries and is programmable to a wide range of voltage and current settings. A quick-test program measures battery state-of-health in three minutes and a boost program reactivates dead batteries. There is even a program to measure the battery self-discharge (HP PAVILION DV2 Battery).

Take care of your battery

It is interesting to note that the batteries which are maintained by one user last longer than those who are part of a fleet of battery self-service because anyone can access it but nobody wants to be responsible. In this article we will discuss two distinct types of users of batteries - the individual user and the operator of a park. This article provides suggestions for extending the life of batteries and increase their reliability in the environment rather drive from one battery set (Sony Vaio VGN-FZ battery).

An individual user is someone who uses a mobile phone, laptop or video camera for business or personal needs. He or she will likely the care of the battery. The user learns the irregularities of the battery. When the operating time decreases, the battery will be sent to maintenance or replacement. The critical failures are rare because the owner of the battery fits in the battery performance and lower their expectations and as it ages (Sony VGP-BPS8 battery). The operator of a fleet of batteries by cons there is very little interest and will have very little tolerance for a case that is not perfect. He grabbed a battery charger and expect it to last throughout his shift. The battery in the charger then returned late in the day, ready to be used by someone else. Perhaps because of negligence batteries forming part of a park usually provide a service life shorter than an individual user (Sony VGP-BPL9 battery).

How can we extend the battery life of a park? An interesting observation can be made by comparing the habits of the U.S. Army and Dutch Army who both use batteries similar to "park". The U.S. Army provides batteries with no maintenance program. If the battery fails, another case is used and no questions asked. Virtually no maintenance is not their given and the failure rate is high (Sony VGN-FZ460E battery).

As against the Dutch army was detached from the battery system in the park by giving soldiers the responsibility of their own batteries.

This change was made to try to reduce operating costs and improve reliability. The batteries are supplied to soldiers like the rest of their equipment and they are now part of their personal affairs. The results are amazing. Since the Dutch military has adopted this new strategy, the failure rate of the batteries has dropped considerably and at the same time the performance of batteries has increased. Unexpected failures have virtually been eliminated (Sony VGP-BPS9battery).

It should be noted that the Dutch army only uses NiCd batteries. Each case receives periodic maintenance on a Cadex battery analyzer to prolong its life. The batteries that do not reach their target capacity of 80 per cent are reconditioned, and those who do not meet this target are replaced. For cons, the U.S. military uses NiMH batteries which are known to have a shorter lifespan. The army is studying lithium batteries for the next generation of batteries (Sony VGP-BPL11 battery).

he battery analyzers for critical missions

The high failure rate for a fleet of batteries, excessive costs of replacing and unreliability has caused many agencies or companies to perform maintenance of rechargeable batteries using battery analyzers on a regular basis . Today the battery analyzers play a role in prolonging the life of the batteries and the upkeep of a fleet of batteries (Sony VGP-BPS11 battery).

Conventional wisdom says that a new battery still works flawlessly. Yet many users notice a fresh battery does not always satisfy the specifications of the manufacturer. With a battery analyzer Weak batteries can be identified and prepared. If the capacity does not improve the enclosures can be returned to the supplier to be replaced under warranty. Lots entirely new batteries are fired because of their unacceptable performance. If these batteries were shipped before an initial inspection, the entire system was compromised, resulting in unpredictable performance and a high failure rate in the batteries (SONY VAIO VGN-FZ4000 Battery).

In addition to the work of preparation of batteries for use in customers, battery analyzers perform the important task of restoring weak batteries and brushing. Low batteries can hide easily among others. But when the system is tested during an emergency situation, those who can not hold on relentlessly emerge from the crowd. It should be noted that the battery analyzers are more effective in restoring the nickel-based batteries. Lithium batteries lose their capacity mainly because of aging and such a performance loss is irreversible (Sony VGP-BPS10 battery).

Organizations tend to push the battery maintenance until a crisis develops. A company of firefighters who used mobile radios experiencing chronic problems of communications, especially during procedures lasting more than two hours. While their radios were working well in reception, firefighters were unable to send anything and they were unaware that their appeals were unsuccessful ( Sony VGP-BPS3 battery).

The company's fire brigade said the acquisition of a Cadex battery analyzer and all underwent a battery maintenance by the methods of exercise and recondition. The batteries that could not pass the test of a predetermined target capacity were replaced .

Shortly after, firefighters were called to action by asking for a ten o'clock intense radio activity. To their surprise, no mobile radios did not fall down. The success of this operation was flawless attributed to the excellent performance of their batteries. The next morning, the head of the company of firefighters personally contacted the manufacturer of battery analyzer and enthusiastically gave his congratulations for the remarkable performance of their aircraft (Sony VGP-BPS2 battery).

The batteries placed in hibernation commonly fail when needed for an emergency. A representative from Cadex was allowed one day to visit the disaster management center to a report in a large city states USA. In a bunker and fortified underground, there were more than a thousand rows of batteries on chargers. All lights Ready were lit, indicating that the batteries were ready to be used in a wink at any time. The officer got up and secure a voice told him "we are ready to confront any state of emergency" (Sony VGP-BPL15 battery).

The Cadex representative then asked the officer to give him a chance to plug in battery charger to check his condition. Within seconds, the battery analyzer detected a fault condition. So to catch the agent gave him another one row of magazines but this one also failed the test. It was the same for others (Sony VGN-FZ460E battery).

Such scenarios are quite common. Bureaucracy, politics and reduced budgets often slow the resolution of these problems. A maintenance program in which each battery through regular maintenance every month on a battery analyzer eliminate such a problem. In the meantime, the only thing the agent of that emergency center can do is pray that no disaster occurs (Apple A1281 battery).

Summary

Unlike batteries, which individual users personally know their batteries as friends, users of Battery Park to share them by ignoring their origin. While an individual user can detect even a tiny reduction in operating the park operators have no way of knowing the behavior or condition of a battery when it is removed from a charger. They are thank you to the battery. It's almost like Russian roulette (Apple M9848LL/A battery).

More and more users of a park set up batteries of battery maintenance programs. Such a plan makes the exercise all the batteries at regular intervals, repackages those who fall below the target capacity and clarifies some bad (Apple A1189 battery).

Usually batteries are sent to maintenance only when they can no longer maintain their office or when they equip the unit is sent for repair.Accordingly, the operation of devices with batteries and is uncertain due to battery failures occur too often. The loss of energy required by the battery is as bad as any other system failure (Apple M8665G/A battery).

The changing demands of modern battery testers

One of the main purposes of a battery analyzer has been to exercise and restore NiCd batteries affected by 'memory'. With today's nickel-free batteries, memory is no longer a problem. Lithium-based batteries do not need a periodic discharge; neither can these batteries be restored through cycling when weak (Sony Vaio VGN-FZ battery).

In this article we examine some of the new duties the modern battery analyzer assumes. These include performance verification through quick testing, energizing batteries that have fallen asleep due to deep discharge and priming new batteries (Sony VGP-BPS8 battery).

Common sense suggests that a new battery should always perform flawlessly, yet many packs fail to meet manufacturer's specifications. With a battery analyzer, incoming batteries can be checked as part of quality control. Packs that perform poorly during the warranty period can be identified and returned for replacement (Sony VGP-BPL9 battery).

The typical life of a Li-ion battery is 300 to 500 discharge/charge cycles or two to three years from time of manufacturing. The loss of battery capacity occurs gradually and often without the awareness of the user. The function of the battery analyzer is to identify weak batteries and "weed" them out before they become a problem. This task is especially pertinent in a fleet environment. The loss of adequate battery power is as detrimental as any other malfunction in the system (Sony VGP-BPS9battery).

A battery analyzer can also trouble-shoot short runtime. This is a common complaint and there are multiple causes that contribute to this problem. In some instances, the battery may not be properly formatted when first put in service. Repeated cycling can correct this. Another problem is incomplete charge when charged with the original charger. A battery analyzer can help in comparing the capacity when charged with the original charger and then comparing it with a full charge provided by the analyzer (Sony VGP-BPL11 battery).

Another common cause of short runtime is high internal battery resistance brought on by use and aging. Many analyzers are capable of measuring the internal battery resistance. Some instruments can simulate the load signature drawn by a digital device to verify the runtime according to load requirements (Sony VGP-BPS11 battery).

Higher than specified power consumption is another reason of short runtimes. This, however, is mostly related to the way the equipment is being used (SONY VAIO VGN-FZ4000 Battery).

Lithium-based batteries are sensitive to aging. If stored fully charged at elevated temperatures, the battery can deteriorate to 50 percent capacity in about one year. Similar performance degradations are observed on NiMH batteries when used under the same conditions. Although still considered new, the user will blame the equipment rather than the battery for poor performance. The analyzer can isolate such problems quickly and accurately (Sony VGP-BPS10 battery).

With the increased dependence on battery power, the need for battery quick testing becomes apparent. Various test schemes have been introduced over the years but none has caught on. Most have inherent problems with accuracy. The battery needs to be fully charged before testing because different charge levels interfere with the state-of-health readings. Defense organizations invest heavily in battery quick testing, only to come up with textbook methods that require large computers that must build up extensive data banks of reference material for each battery type checked. In addition, the test time is often too long to be practical ( Sony VGP-BPS3 battery).

Cadex Electronics has developed a technique that measures the state-of-health of a battery in three minutes. Based on inference technology, the Cadex Quicktest™ uses battery specific matrices that are derived through a "trend learning" process using artificial intelligence. The ability to self-learn enables the system to adapt to new battery chemistries without having to change hardware (Sony VGP-BPS2 battery).

Figure 1: Cadex 7400 battery analyzer

Quicktest is available on the Cadex 7200 (two-station) and 7400 (four-station) battery analyzer/ reconditioners. The system accommodates Li-ion, NiMH, NiCd and lead acid batteries; the required charge level is 20 to 90 percent. If outside this range, the analyzer automatically applies a brief charge or discharge. The charge level within this acceptable range does not affect the state-of-health readings (Sony VGP-BPL15 battery).

The matrix obtained through Learn is stored in the battery adapters that also contain the battery parameters to configure the analyzer. One Learn cycle is the minimum requirement to develop a working QuickTest matrix. Better results are achieved when learning several batteries with varying state-of-health conditions. Once attained, the matrix can be copied to other battery adapters. Testing a battery with a properly learned matrix achieves an accuracy of +/-5 percent on most batteries. Popular custom adapters offered by Cadex include the matrix at time of purchase (Sony VGN-FZ460E battery).

The Cadex QuickTest helps customer service staff to examine batteries at point-of-sales. For service centers, QuickTest is capable of quickly separating serviceable batteries from those that exhibit genuine defects. A full maintenance program may be needed to repair those batteries that are serviceable (Apple A1281 battery).

A common Li-ion battery failure is caused by excessive low discharge. This deactivates the internal safety circuit and the battery appears dead. The Boost program of the Cadex 7000 Series analyzers applies a gentle current to energize the battery. Once the voltage reaches charging range, a full service program verifies the battery (Apple M9848LL/A battery).

To prove the effectiveness of the Boost program, Cadex has tested a large number of supposedly dead Li-ion polymer batteries from various manufacturers. When first measured, these batteries had no voltage and appeared dead. Charging the packs in their respective chargers was unsuccessful. After boosting, most batteries accepted normal charge. The analyzer applied a full service program and attained capacities of 80 percent and higher in most batteries. All restored packs performed flawlessly when returned to service (Apple A1189 battery).

Boosting Lithium-based batteries is safe. However, if the cell voltage has fallen to 1.5 volts and has dwelled in that state for several days, a recharge should be avoided. A very deep discharge may form copper shunts in the cells, which can develop an electrical short. The Cadex battery analyzers identify such faults and terminate service (Apple M8665G/A battery).

Nickel-based batteries can also benefit from the Boost program. Older batteries or those with advanced cycle count exhibit high self-discharge, a condition that cannot be corrected. If activated with Boost and left unattended, the battery may revert back to its former state (Apple M9677*/A battery).

Figure 2: Cadex FlexArm.

The Cadex FlexArm requires setting of battery chemistry, voltage and mAh rating. The Edit key on the Cadex battery analyzer prompts the user to enter the specifications. The battery setting is stored in the FlexArm. There is room to store 10 individual battery types, each of which can be given a unique name （Apple A1148 battery）.

To check batteries with the Cadex QuickTest, a common matrix may be used for packs that have similar chemistry, voltage and capacity rating. This applies to cell phone batteries consisting of a single Li-ion cell. If the readings are inaccurate, a separate matrix will be required for these batteries (Apple 661-2183 battery).

The Cadex FlexArm is best suited for technicians dealing with constantly changing batteries. However, large groups of identical batteries (fleet environment) are best served with custom adapters. These adapters are programmed at the factory and do not require setting of battery parameters (Apple M9419ZH/A battery).

Using the FlexArm together with the Cadex BatteryShop software allows for some interesting simplifications. All the user does is clicking the mouse on the selected battery and the analyzer configures to the correct parameters, ready for service (Apple M9007LL/A battery).

Programming the analyzer by scanning the battery model is also possible. The model number is matched with the listing in the battery database and the correct parameters are assigned. BatteryShop is capable of generating bar code labels on demand (Apple M9008J/A battery) .

The Internet is poised to play a pivotal role in battery testing. Batteryshop will be able to fetch C-Codes and matrices of new batteries, send battery test results to a central location, and download firmware to upgrade existing equipment. Batteryshop is equally proficient supporting one analyzer or a fully extended system of 120 units (HP PAVILION DV9700t Battery).

Summary

With batteries flooding the market, the availability of suitable equipment to test them may outpace battery production. This void is especially apparent in the mobile phone market where large quantities of batteries are being returned under warranty. Many of these presumably faulty packs are discarded without checking or attempting to restore them. In the end, the customer will pay with higher prices (HP PAVILION DV2 Battery).

Testing and restoring batteries has become a complex assignment. Battery analyzers must be simple to operate and allow customer service staff to perform the task without much training. Properly used, these instruments will assist in managing the influx of returned batteries. The quick-test feature can sort packs that are serviceable from those that exhibit genuine defects. PC software assists in programming the analyzer and keeping pace with new battery arrivals. The Internet makes updating easy (HP PAVILION DV2000 Battery).

Battery testing also serves public safety organizations, rental outfits and defense organizations. With the quick-test feature, a battery can be examined prior to releasing to a customer or assignment for a critical mission. Testing by applying a full charge and discharge cycle is simply not practical. Being able to verify battery performance on the fly, only those packs are released that are fit for the job (HP PAVILION DV3000 Battery).