To estimate capacity and state-of-charge on the fly

June 17 [Mon], 2013, 15:13
The resistance of a battery provides useful information about its performance and detects hidden trouble spots. High resistance values are often the triggering point to replace an aging battery, and determining resistance Aspire 3820T replacement is especially useful in checking stationary batteries. However, resistance comparison alone is not effective, because the value between batches of lead acid batteries can vary by eight percent.

Because of this relatively wide tolerance, the resistance method only works effectively when comparing the values for a given battery from birth to retirement. Service crews are asked to take a snapshot of each cell at time of installation and then measure the subtle changes as the cells age. A 25 percent increase in resistance over the original reading hints to an overall performance drop of 20 percent.

Manufacturers of stationary batteries typically honor the warranty if the internal resistance increases by 50 percent. Their preference is to get true capacity readings by applying a full discharge. It is their belief that only a discharge can provide reliable readings and they ask users to perform the service once a year. While this advice has merit, a full discharge requires a temporary disconnection of the battery from the system, and on a large battery such a test takes an entire day to complete. In the real world, very few battery installations receive this type of service and most measurements are based on battery resistance readings.

Measuring the internal resistance is done by reading the voltage drop on a load current or by AC impedance. The results are in ohmic Aspire 3935 replacementvalues. There is a notion that internal resistance is related to capacity, and this is false. The resistance of many batteries stays flat through most of the service life.

To estimate capacity and state-of-charge on the fly involves impedance trending by scanning a battery with frequencies ranging from less than one hertz to several thousand hertz. Read more about Testing Lead Acid Batteries.

A dead battery is easy to measure and all testers

June 17 [Mon], 2013, 15:12
A German manufacturer of luxury cars points out that one out of two starter batteries returned under warranty is working and has no problem. It is possible that battery testers used in service garages did not detect the Aspire 1551 replacementcorrectly before they were returned under warranty. ADAC* reported in 2008 that 40 percent of all roadside automotive failures are battery-related. In Japan, battery failure is the largest single complaint among new car owners.

The average car is driven 13km (8 miles) per day and mostly in congested cities. The most common reason for battery failure is undercharge. Battery performance is important; problems during the warranty period tarnish customer satisfaction.

Battery malfunction during the warranty period is seldom a factory defect; driving habits are the culprits. A manufacturer of German-made starter batteries stated that factory defects account for only 5 to 7 percent of warranty claims. The battery remains a weak link, and is evident when reviewing the ADAC 2008 report for the year 2007. The study examines the breakdowns of 1.95 million vehicles six years old or less, and Table 1 provides the reasons.

The cellular phone industry experiences an even more astonishing battery return pattern. Nine out of 10 batteries returned under warranty have no problem or can easily be serviced. This is no fault of the manufacturers but they pay a price that is ultimately charged to the user.

Part of the problem lies in the difficulty of testing batteries at the consumer level, and this applies to storefronts and service garages alike. Battery rapid-test methods seem to dwell in medieval times, and this is especially evident when comparing advancements made on other fronts. We don’t even have a reliable method to estimate state-of-charge — most of such measurements using voltage and coulomb counting are guesswork. Assessing capacity, the most reliable health indicator of a battery, dwells far behind.

The battery user may ask why the industry is lagging so far behind. The answer is simple: battery testing and monitoring is far more complex than outsiders perceive it. As there is no single diagnostic device that can assess the health of a person, so are there no instruments that can quickly check the state-of-health of a Aspire 3810T replacement. Like the human body, batteries can have many hidden deficiencies that no single tester is able to identify with certainly. Yes, we can apply a discharge, but this takes the battery out of service and induces stress, especially on large systems. In some cases, even a discharge does not provide conclusive results either. Read more about Discharge Methods.

As doctors will examine a patient with different devices, so also does a battery need several approaches to find anomalies. A dead battery is easy to measure and all testers can do this. The challenge comes in evaluating a battery in the 80 to 100 percent performance range. This chapter examines current and futuristic methods and how they stand up. One thing to remember is this: batteries cannot be measured; the appropriate instruments can only make predictions or estimations. This is synonymous with a doctor examining a patient, or the weatherman predicting the weather. All findings are estimations with various degrees of accuracies.

The first non-rechargeable lithium batteries

May 02 [Thu], 2013, 15:44
When Sony introduced the first lithium-ion battery in 1991, they knew of the potential safety risks. A recall of the previously released rechargeable metallic lithium battery was a bleak reminder of the discipline one must exercis XPS 17 brand new e when dealing with this high energy-dense battery system.

Pioneering work for the lithium battery began in 1912, but is was not until the early 1970's when the first non-rechargeable lithium batteries became commercially available. Attempts to develop rechargeable lithium batteries followed in the eighties. These early models were based on metallic lithium and offered very high energy density. However, inherent instabilities of lithium metal, especially during charging, put a damper on the development. The cell had the potential of a thermal run-away. The temperature would quickly rise to the melting point of the metallic lithium and cause a violent reaction. A large quantity of rechargeable lithium batteries had to be recalled in 1991 after the pack in a cellular phone released hot gases and inflicted burns to a man's face.

Because of the inherent instability of lithium metal, research shifted to a non-metallic lithium battery using lithium ions. Although slightly lower in energy density, the lithium-ion system is safe, providing certain precautions are met when charging and discharging. Today, lithium-ion is one of the most successful and safe battery chemistries available. Two billion cells are produced every year.

Lithium-ion cells with cobalt cathodes hold twice the energy of a nickel-based battery and four-times that of lead acid. Lithium-ion is a low maintenance system, an advantage that most other chemistries cannot claim. There is no memory and the battery does not require scheduled cycling to prolong its life. Nor does lithium-ion have the sulfation problem of lead acid that occurs when the battery is stored without periodic topping charge. Lithium-ion has a low self-discharge and is environmentally friendly. Disposal causes minimal harm.

Long battery runtimes have always been the wish of many consumers. Battery manufacturers responded by packing more active material into a cell and making the electrodes and separator thinner. This enabled a doubling of energy density since lithium-ion was introduced in 1991.

The high energy density comes at a price. Manufacturing methods become more critical the denser the cells become. With a separator thickness of only 20-25μm, any small intrusion of metallic dust particles can have devastating consequences. Appropriate measures will be needed to achieve the mandated safety Presario A900 brand newstandard set forth by UL 1642. Whereas a nail penetration test could be tolerated on the older 18650 cell with a capacity of 1.35Ah, today's high-density 2.4Ah cell would become a bomb when performing the same test. UL 1642 does not require nail penetration. Lithium-ion batteries are nearing their theoretical energy density limit and battery manufacturers are beginning to focus on improving manufacturing methods and increasing safety.

This is a fraction of a battery cycle in the same way as any other charge

May 02 [Thu], 2013, 15:05
There are a number of misunderstandings about how rechargeable batteries work in most modern electronic devices, most likely RM791 brand new caused by some significant advances in battery technology over the years.

The first and most important consideration is that the majority of modern electronic devices with rechargeable batteries now use “Lithium Ion” batteries (Li-ion). Unlike earlier generations of rechargeable batteries which were based on Nickel Cadmium (NiCad) or Nickel Metal Hydride (NiMH), Lithium Ion batteries do not suffer from the “memory effect” when it comes to recharging. Previous Nickel-based rechargeable batteries, particularly NiCad batteries, would lose their maximum charge capacity if they were not fully discharged prior to charging them up.

Li-ion batteries, on the other hand, actually prefer to be topped up, and should never be completely discharged, as this will actually destroy the battery. Most electronic devices, including the iPod, have a cut-off circuit that turns the device off when the battery drops critically low in order to prevent this from happening, thereby leaving a small charge in the battery, so this is rarely a practical concern for an end user.

Likewise, while lithium-ion batteries can technically experience problems from overcharging (continuing to charge the device after the battery is fully charged), any properly-designed electronic device will incorporate a “cut-off” circuit to stop charging the battery once it’s reached its full charge level in order to prevent this.

Another point to note is that there is no requirement for a lithium-ion battery to be “primed” before use. Recommendations that a new iPod be plugged in and charged overnight before using it for the first-time are based on older nickel-based battery technology. For a Li-ion battery, there is no difference between the first charge, the tenth charge, or the 100th charge.

The life expectancy of a lithium ion battery in terms of how many charges it will take is measured in “charge cycles” which refers to the number of complete discharge and recharge cycles, not simply to the number of times the battery is “topped up.” Therefore, if you drain your battery by 25% and recharge it fully four times, this will count as a single charge cycle. Again, there is rarely a reason for the average iPod user to worry about watching the charge level or being concerned about reaching a certain level before recharging—simply dropping the iPod into the charger whenever necessary is fine.

In fact, the only reason in the case of an iPod for doing a complete discharge and recharge of an iPod is to re-calibrate the battery meter itself (ie, the iPod’s display of how much power is remaining). This has no impact on the actual battery life, but will help the iPod provide a better estimation of the remaining life for the user by ensuring the battery gauge is accurate.

In terms of how the charging process itself works, Li-ion batteries charge in two stages: If the battery is below approximately 70-75% charge level, the first stage involves applying full charging power to get the battery charge up to that level. Once the battery reaches the 70-75% level, a “topping” charge is applied, whereby the current to the battery is gradually decreased as the battery capacity reaches 100%. This is done in order to avoid overcharging, and is sometimes referred to as a “trickle” charge, although this is technically incorrect by definition, since a “trickle charge” refers to continuous power being applied to a battery once it has reached full charge, which Li-ion batteries do not do, again in order to avoid the risk of overcharging.

With a Li-ion battery, once full charge has been reached, the charging circuit will shut off completely and stop providing any charge to the battery. At this point, as long as the device remains connected to external power, the battery goes dormant and the device simply runs from the external power source. What this means for the iPod is that as soon as you see the “Plug” icon on the battery indicator, charging power has been cut-off and the device is simply running from the external power source.

If you leave the iPod connected to an external power source for long enough, the battery will drop slightly in power just from normal energy loss (in the same way that it would if it were simply sitting on a shelf turned off). Once the battery falls below a certain level, a topping charge will be reapplied to bring it back to full, but this normally happens very infrequently as long as the device remains connected to external power—possibly as rarely as only once every three to four weeks.

Disconnecting the iPod from external power and reconnecting it will re-initiate the charge circuit, since the battery level needs to be re-checked, and a small topping charge may need to be applied to get back to 100%, but unless the device has been used on battery, the iPod should return to the plug icon within a few minutes, once again indicating that the battery is fully charged and the device is running from AC power. In many cases no topping charge is applied, and this delay is just the time it takes for the iPod to resolve that the battery is, in fact, fully charged.

The net effect of disconnecting and reconnecting your iPod from its dock should be basically neutral in terms of battery life. The topping charge is applied only to bring the battery back to 100%, so this is a fraction of a battery cycle in the same way as any other charge.

Unfortunately, many of the now-outdated issues with nickel-based batteries have become urban myths for modern electronic devices, and can cause many iPod owners much completely unwarranted angst about their device and their battery life. In reality it is almost never necessary for a typical iPod user to worry much about the iPod battery… The simple rule of thumb is to use the device as you normally would, charge it when it needs it, and don’t worry too much about leaving it on the charger for reasonable periods of time.

In fact, just about the only issue to be aware of is for those rare users who use their iPod from external power all the time. In this case, since the Li-ion battery is not being used (the device is running from external power), the Vostro 1310 brand newitself doesn’t get properly “exercised” and this can decrease the battery life over time.

This is only an issue for users who almost never run their iPod from the battery. Apple’s own support site simply suggests that the battery be put through at least one complete charge cycle per month. Considering that even twenty 5% “top-up” charges still counts as a charge cycle, the reality is that for the vast majority of iPod users, normal everyday use will easily take care of this.

Some people we know get by fine with less storage in relation

January 15 [Tue], 2013, 11:24
Selecting the brand, size and number of batteries you need can be a little tricky. It depends on the average daily output of your solar array (see Countryside May/June 2007, "Calculating Your Daily Solar Energy Harvest"); your home's daily energy demands; the amount of stored energy you'd like to keep i battery for Presario CQ50 batteryn reserve; and, of course, what you can comfortably afford. Generally you will want a battery bank sufficiently small that you can return it to a full charge at least every few days, but large enough that it will be able to hold the extra power reserves you'll need to tide you over for two or three consecutive cloudy days.

In sunny Colorado, LaVonne and I can easily bring a 28,000 watt-hour (1,200 amp hours @ 24 volts) bank of 12 Trojan L16 batteries from a 70 percent charge to a full charge in less than two sunny, breezy days, without working particularly hard at saving energy. We do it with a 1,640-watt solar system capable of producing over nine kilowatt hours on a good day, and a 1,000 watt Bergey XL.1 wind turbine that's usually good for a couple of kilowatt hours.

It's a system we're comfortable with. Some people we know get by fine with less storage in relation to their solar and wind output, others with more. In the end, you'll find that you either adapt to your system, or you battery for Presario CQ56 batterychange it. And therein lies the key to successful off-grid living: be flexible—in the way you design your system, and the way you live within its limits.

These are not small batteries

January 15 [Tue], 2013, 11:05
Not too many years ago, there were basically two choices: T-105s or L16s. The T-105, made by the Trojan Battery Company (, is the basic golf-cart-style battery. These batteries are light (62 pounds), cheap (around $90 to $100), and will last anywhere from three to six years or longer, depending on how they're maintained and how extensively they are used. We've had a battery for Presario CQ43 batterybank of these in our guest cabin for eight years and, as a result of good maintenance and very little use, they're still going strong.

The L16-style battery is the next step up the line. This battery is considerably more rugged than the T-105. Popularized by Trojan but manufactured by several different companies, these batteries generally weigh in at around 120 pounds and cost in the neighborhood of $220 each. If properly maintained, a hardworking bank of L16s can last eight years or longer. (We have two banks of 12 Trojan L16 batteries in our house, for a total of 24. Switching from bank to bank ensures that neither battery bank ever becomes more than 35 percent discharged, a system designed to greatly extend battery life.)

Surrette batteries, manufactured in Canada (, are finding their way into more and more off-grid homes, particularly as off-grid systems become larger and more demanding. Big, heavy and rugged, these batteries are built to last 12 to 15 years or longer, as evidenced by the 10-year warranty they carry. Surrette offers a number of battery sizes and types from two to twelve volts over a wide range of capacities, so it's possible to size a bank of Surrettes for almost any system.

If you're really serious about going off grid with a large solar array and you insist on top-of-the-line batteries, then HUP Solar One batteries (, manufactured by General Battery, may be just the workhorses you've been looking for. General Battery has developed a patented process that uses Teflon to stabilize the lead paste that covers the positive plates (hence HUP for High Utilization Positive) of these huge batteries.

The result of this innovation is a battery that can take intense use (which is not to say neglect or abuse) over many years. In fact, Solar One batteries are warranted to endure 2,100 cycles of 80-percent discharge, or 4,000 cycles of 50-percent discharge. This is equivalent to using half the energy in your battery for Presario CQ45 batteryevery day for nearly eleven years, something that would never ever happen with a properly sized solar/wind charging system.

As you might imagine, these are not small batteries. Solar One's 12-volt batteries—the basic building blocks of their 24- and 48-volt batteries—all stand 25 inches high and weigh from 742 pounds for the 845 amp-hour size, to 1,336 pounds for the 1,690 amp-hour giants. So in addition to a suitably large solar array, you'll need either a forklift or a football team to set them in place.

Never have the electrolyte level drop below a marked minimum on the cell

November 28 [Wed], 2012, 12:22

Their average temperature. Choose the coolest possible place for them. The area must be well ventilated.

Avoid temperature differences between bottom and top of the cell. A battery should be surrounded by air. They should not stand on a cold concrete floor, but placed on wooden support and provide air gaps in between the 11.1v 5200mah 9cells Presario CQ40 battery different units. Whole the battery should have more or less the same temperature. This to avoid stratification of the electrolyte due to temperature differences.

Correct charging is essential. Most batteries come with specific instructions regarding the optimal charge conditions. Invest in a modern, electronically regulated charger. Many modern inverters come with a built in charger. Avoid deep discharges and never leave the battery in a discharged state. Vented batteries profit from periodical overcharging. During a short period of time, the voltage of the charger is kept over the normal limit of 2.4 V per cell (for example during 30 min) causing excessive gassing of the batteries.

This process, called, equalizing, will equalize the electrical charge over the all the plates in their different cells, while the bubbling replacement Presario CQ42 batteryliquid helps cleaning the plates and will remix the electrolyte.

Never have the electrolyte level drop below a marked minimum on the cell. If a plate is not covered with electrolyte it will cause serious sulphation and sometimes deformation of the plate

Lithium Ion batteries have great performance

November 28 [Wed], 2012, 12:17
I was standing in line at a local electronics store the other day when I struck up a conversation with the guy ahead of me who had a basket full of battery chargers and AA rechargeable batteries. It turns out he had decidedbattery for Presario A900 battery to replace all of the batteries in his house with the rechargeable kind. Between the batteries and the chargers this guy plunked down over a hundred bucks!

He was so proud, telling me about all the money he was going to save.

I didn’t have the heart to ask him if he had the same typical electronic devices found in most homes, because if he did then he probably ended up spending a lot more money than he should have.

Rechargeable Batteries Aren’t Always Cost Effective!

I realize many people want to convert to rechargeable batteries for environmental reasons, which is fair enough. But the truth of the matter is this: when cost is the primary discriminator, low current-draw devices simply don’t warrant the extra expense of rechargeable batteries. That’s because the batteries of low current-draw devices are typically changed so infrequently that the payback period for equivalent rechargeable batteries would be too far long to justify the investment!

For example, it makes much more sense to use traditional alkaline batteries for low-draw devices like your wall clocks, radios, smoke detectors, programmable thermostats, and remote controls because they lose power at a much slower rate than rechargeable batteries.

And because traditional alkaline batteries can hold a charge for years when not in use, they are also the better choice for items that may sit unused for long period of time, like your alarm clock back-up battery and emergency flashlights.

When it comes right down to it, these low current-draw and/or low-use devices make up the great majority of battery-driven products in the typical home.

Okay. So When Do Rechargeable Batteries Make Sense?

Rechargeable batteries are really intended for moderate to high current-draw devices that get at least moderate use. Typically, these are devices that require a battery change every 30 to 60 days.

In my house the only item that clearly met that criteria and, therefore, justified the added up-front costs of rechargeable batteries, was the kids’ Wii gaming system. That is a perfect example of a high-use device where rechargeable batteries will save you a lot of money in the long run.

But for my household those are the only items where rechargeable batteries make sense.

“But, Len, what about my wireless keyboards and mice? Those get a lot of use!”

Well, as my article on the practicality of wireless mice and keyboards noted, rechargeable batteries didn’t even make financial sense for those devices, based upon my battery usage over an 18-month period – I only spent a little over $18 on replacement batteries during that period. But a set of eight good rechargeable AA batteries (five for the mouse and keyboard plus three spares) would set me back roughly $24. Add in the cost of the charger (a good one can run upwards of $40) and you can see that the payback period on the rechargeable batteries becomes a real issue. Remember, rechargeable batteries eventually go bad too, so you’ll need your batteries and charger to last at least until the payback period is reached if you want to recoup your costs in a reasonable amount of time.

How Do I Know Which Type of Rechargeable Battery to Buy?

If and when you decide you want to buy rechargeable batteries, you’ll need to know that there are essentially four types to choose from: nickel metal-hydride (NiMH), nickel cadmium (NiCad), rechargeable alkaline, and lithium ion.

NiMH rechargeable batteries typically perform better than NiCads and are free of toxic heavy metals. Generally speaking, NiMH is the best all-around choice for most rechargeable battery applications. As an added bonus, most NiMH battery charger systems can accommodate NiCad batteries too (although the opposite is not true).

NiCads are being phased out in favor of NiMHs not only because they are losing the performance war, but also because of their inconvenience; the heavy metals used within the NiCad are toxic and require special disposal needs.

Rechargeable alkaline batteries have only two real advantages over NiMHs and NiCads: low cost and no need for special recycling. Otherwise, their long-term performance and recharge characteristics make these batteries a poor choice. Rechargeable alkaline batteries also require a special charger, which reminds me: don’t ever confuse rechargeable alkalines with the typical disposable alkaline batteries that are sold everywhere from 99-cent stores to the local grocery market – although some people do it, those batteries cannot be safely charged.

Rechargeable alkaline batteries have only two real advantages over NiMHs and NICas:low cost and no need for special recycling.Otherwise,their long-term performance and recharger characteristics make these bright Presario C700 batterya poor choice.Rechargeable alkaline batteries also require to the local grocery market-although some people do it,those batteries cannot safely charge.

Lithium Ion batteries have great performance and can go unused for long periods without losing their charge.The big drawback is their price;not only are lithium ion batteries much more expensive than other types of require to the local grocery market-although some people do it,those batteries cannot safely charge.

Batteries are not 100% efficient - some energy

October 10 [Wed], 2012, 15:04
A battery, in concept, can be any device that stores energy for later use. A rock, pushed to the top of a hill, can be considered a kind of 9cells Pavilion Mini 311 battery since the energy used to push it up the hill (chemical energy, from muscles or combustion engines) is converted and stored as potential kinetic energy at the top of the hill.

Later, that energy is released as kinetic and thermal energy when the rock rolls down the hill. Not real practical for everyday use though.

Common use of the word, "battery" in electrical terms, is limited to an electrochemical device that converts chemical energy into electricity, by a galvanic cell.

A galvanic cell is a fairly simple device consisting of two electrodes of different metals or metal compounds (an anode and a cathode) and an electrolyte (usually acid, but some are alkaline) solution. A "Battery" is two or more of those cells in series, although many types of single cells are usually referred to as batteries - such as flashlight batteries.

As noted above, a battery is an electrical storage device. Batteries do not make electricity, they store it, just as a water tank stores water for future use. As chemicals in the battery change, electrical energy is stored replacement HSTNN-CB73or released. In rechargeable batteries this process can be repeated many times.

Batteries are not 100% efficient - some energy is lost as heat and chemical reactions when charging and discharging. If you use 1000 watts from a battery, it might take 1050 or 1250 watts or more to fully recharge it.

Laptops are available in many different specifications in relation to its screen sizes

October 10 [Wed], 2012, 15:02
When shopping for a new laptop, you want to want to find one at the cheapest possible price. Cost is the primary concern for most people when shopping. With technology advancing at a rapid pace in the last few decades and with hp 504610-001 laptop batteryretailers offering discounts and special offers in order to entice to buy the laptop.

Laptops have now become affordable to the average consumers who are on a budget. Just because you are looking for a cheap laptop does not mean you have to sacrifice any of the features or performance of the laptop.

Laptops are available in many different specifications in relation to its screen sizes. It is best to go for a laptop that has a medium size screen as it will be easy to carry around with you if travelling from one place to another. An important aspect of a laptop is the processor as this will dictate the performance and how well the applications run. Standard laptops today will have a dual core processor with either Intel or AMD being the preferred choice. Laptops can be just used for simple tasks such as web browsing, checking emails and running office applications. The amount of RAM memory inside the laptop can considerably increase or decrease its performance. The minimum memory found in laptop is 1GB but can all the way to 8GB.

Other important specifications to look at are the hard drive, graphics cards and any optical drives (CD or DVD). The majority of people will want to use the laptop in order to connect the internet and that is why you should check whether the laptop has built in Wi-Fi or has a Gigabit Ethernet Network card.

It is best to write down a list of your requirements as you will be clear in your mind as to what you want. By having a list it will eliminate any unnecessary options out there. Set a budget on how much you are going to spend on the laptop as you do not want to go over your budget for a laptop that does not meet your requirements.

When doing your research for a laptop, it is best to shop online as you will be able to compare several laptops at once as this will enable you to look over the specifications that each device has. Online forums and review websites is another area that you will need to look at, as this will give you an idea as tocheap Pavilion dm4 battery what other people have said about a particular laptop that you may be interested in.

If you need to see the product in action, then it is best to go the retailers' store as there you will be able to test how well the machine works and how it looks and feels.

It is important that you carry out thorough research before making your laptop purchase as you do not want to buy a laptop that is too expensive or are not going to use all of its features.