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.

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).